EDITION 8 A POCKET GUIDE TO DOSAGE CALCULATION AND DRUG PREPARATION Mary Jo Boyer, RN, PhD Vice Provost and Vice President Branch Campus Operations Adjunct Nursing Faculty Former Dean and Professor of Nursing Delaware County Community College Media, Pennsylvania (021) 66485438 66485457 LWBK914-FM_pi-xvi.indd i www.ketabpezeshki.com 08/11/11 6:21 PM Acquisitions Editor: Hilarie Surrena Product Manager: Laura Scott Design Coordinator: Joan Wendt Illustration Coordinator: Brett MacNaughton Manufacturing Coordinator: Karin Duffield Prepress Vendor: Aptara, Inc. 8th edition Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins. Copyright © 2006 and 2002 Lippincott Williams & Wilkins. Copyright © 1998 Lippincott-Raven Publishers. Copyright © 1994 J.B. Lippincott Company. All rights reserved. This book is protected by copyright. No part of this book may be reproduced or transmitted in any form or by any means, including as photocopies or scanned-in or other electronic copies, or utilized by any information storage and retrieval system without written permission from the copyright owner, except for brief quotations embodied in critical articles and reviews. Materials appearing in this book prepared by individuals as part of their official duties as U.S. government employees are not covered by the above-mentioned copyright. To request permission, please contact Lippincott Williams & Wilkins at 2001 Market Street, Philadelphia, PA 19103, via email at
[email protected], or via our website at lww.com (products and services). 9 8 7 6 5 4 3 2 1 Printed in China Library of Congress Cataloging-in-Publication Data Boyer, Mary Jo. Math for nurses : a pocket guide to dosage calculation and drug preparation / Mary Jo Boyer.—8th ed. p. ; cm. Includes bibliographical references and index. ISBN 978-1-60913-680-2 (alk. paper) I. Title. [DNLM: 1. Pharmaceutical Preparations–administration & dosage– Handbooks. 2. Pharmaceutical Preparations–administration & dosage– Nurses’ Instruction. 3. Dosage Forms–Handbooks. 4. Dosage Forms–Nurses’ Instruction. 5. Drug Dosage Calculations–Handbooks. 6. Drug Dosage Calculations–Nurses’ Instruction. 7. Mathematics– Handbooks. 8. Mathematics–Nurses’ Instruction. QV 735] LC classification not assigned 615.1′4—dc23 2011030507 (021) 66485438 66485457 LWBK914-FM_pi-xvi.indd ii www.ketabpezeshki.com 08/11/11 6:21 PM Care has been taken to confirm the accuracy of the information presented and to describe generally accepted practices. However, the author, editors, and publisher are not responsible for errors or omissions or for any consequences from application of the information in this book and make no warranty, expressed or implied, with respect to the currency, completeness, or accuracy of the contents of the publication. Application of this information in a particular situation remains the professional responsibility of the practitioner; the clinical treatments described and recommended may not be considered absolute and universal recommendations. The author, editors, and publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accordance with the current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any change in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new or infrequently employed drug. Some drugs and medical devices presented in this publication have Food and Drug Administration (FDA) clearance for limited use in restricted research settings. It is the responsibility of the health care provider to ascertain the FDA status of each drug or device planned for use in his or her clinical practice. LWW.com (021) 66485438 66485457 LWBK914-FM_pi-xvi.indd iii www.ketabpezeshki.com 08/11/11 6:21 PM Dedication Math for Nurses was first published in 1987. At that time I was a professor of nursing at Delaware County Community College. Brian was 7 years old, and Susan was 12 months old. This is now the eighth edition. I’ve dedicated previous books to my students, professional colleagues, friends, and family. However, over the years, it is my family who has continued to energize, support, and encourage my academic and creative interests. So, for this edition, I salute, honor, and thank my family again for always being there. Ermelina: my mother, who is 90 going on 75 Susan: a University of Richmond graduate, working in the finance world for the government in Washington, D.C. Brian: a mathematics high school instructor, pursuing two master’s degrees while also teaching at the college level Kristen: my new daughter-in-law, who embraces family and faith as life’s priorities Sadie: my darling granddaughter, whose laughter lights up all of our lives Bill: my husband and partner since 1974 Thanks Guys! iv (021) 66485438 66485457 LWBK914-FM_pi-xvi.indd iv www.ketabpezeshki.com 08/11/11 6:21 PM Contributors Brian D. Boyer, as, ba Mathematics Instructor Phoenixville High School Phoenixville, Pennsylvania Elaine Dreisbaugh, rn, msn, cpn Associate Professor of Nursing Delaware County Community College Media, Pennsylvania Former Nurse Educator, The Chester County Hospital West Chester, Pennsylvania Kathleen C. Jones, rn, msn, cde Certified Diabetic Nurse Educator The Outpatient Diabetes Program The Chester County Hospital West Chester, Pennsylvania Joanne O’Brian, rn, msn Associate Professor of Nursing Delaware County Community College Media, Pennsylvania Nurse Educator, The Chester County Hospital West Chester, Pennsylvania v (021) 66485438 66485457 LWBK914-FM_pi-xvi.indd v www.ketabpezeshki.com 08/11/11 6:21 PM msn Assistant Professor Georgia Baptist College of Nursing of Mercer University Atlanta. msn. rn. phd.Reviewers Ginger Christiansen. msn Nurse Faculty Jefferson State Community College Birmingham.ketabpezeshki. msn. rn. Alabama Audrey N. rn.com 08/11/11 6:21 PM . Associate Degree Nursing Tyler Junior College Tyler. msn. Keister. Texas M. Wisconsin Kelli Lewis Rend Lake College Ina. Ohio Lori Kulju. Jones. Ohio Susan Estes-Blakey. Alabama Kathy J.indd vi www. Kathleen Dwinnells. Illinois vi (021) 66485438 66485457 LWBK914-FM_pi-xvi. rnc. cns Assistant Professor of Nursing Kent State University at Trumbull Warren. rn Professor. cne Associate Professor Wright State University College of Nursing & Health Dayton. rn. msn Instructor Gadsden State Community College Gadsden. rn Assistant Professor Bellin College Green Bay. Georgia Debra Ferguson. Smith. edd. Tennessee (021) 66485438 66485457 LWBK914-FM_pi-xvi. rn.com 08/11/11 6:21 PM .ketabpezeshki. Texas Melinda Wang Roane State Community College Knoxville. rn.Reviewers vii Laura Burgess Patton. New York Koreen W. rn. msn. Missouri Sherri L.indd vii www. rn Associate Professor Nova Southeastern University Fort Lauderdale. mn Professor of Nursing Gordon College Barnesville. Florida Lee Ann Waltz University of the Incarnate Word San Antonio. msn. Smiley. rn Practical Nursing Program Chairman Arkansas State University Technical Center Jonesboro. Romero. msed Nursing Professor St. Arkansas Lisa Soontupe. Georgia Lisa Richwine Ivy Tech Community College Anderson. cnm Retired Nursing Instructor East Los Angeles College Monterey Park. Indiana Laura R. California Lynda Shand College of New Rochelle New Rochelle. Charles Community College Cottleville. indd viii www. Work the practice problems. “Why not?” The idea was born. I also noted that staff nurses were using this readily available and compact information as a reference for math problems. • To serve as a quick reference when reinforcement of learning is required. The best way to use this pocket guide is to: • • • • Read the rules and examples. the commitment made. Follow the steps for solving the problems. and 18 months later the first edition of Math for Nurses was published in 1987. It is my hope that it will continue. For several years I watched as they took their math-related handouts and photocopied them.ketabpezeshki.Preface T he idea for this compact. How to Use This Book This book is designed for two purposes: • To help you learn how to quickly and accurately calculate drug dosages and administer medications. Organization This pocket guide is divided into three units to facilitate quick access to specific information needed to administer viii (021) 66485438 66485457 LWBK914-FM_pi-xvi. Each year the number of papers that were copied increased as each group of students passed on their ideas to the next group. to be helpful to all who need a quick reference source when struggling with dosage calculations and drug preparation. in this eighth edition. When a student asked. “Why not put together for us all the information that we need?” I thought. pocket-sized book about dosage calculation was generated by my students. reducing them to a size that would fit into the pockets of their uniforms or laboratory coats. This “pocket” reference material was readily accessible when a math calculation was needed to administer a drug.com 08/11/11 6:21 PM . Write down your answers and notes in the margin so that you have a quick reference when you need to review. is also incorporated into every drug calculation. is the most comprehensive and detailed section of this pocket guide. weight-based heparin (Chapter 13). Unit 1 presents a review of basic math. Chapters 2 and 3 cover common fractions and decimals. Ratio and proportion and the Formula Method are used for every problem. Dosage Calculations. This unit information is essential. and expanded examples of drug reconstitution (Chapter 15). Critical care applications have also been expanded in Chapter 11.indd ix www. The last four chapters incorporate intravenous insulin (Chapter 12). which will guide the reader through each set of examples. Some of these system equivalents are duplicated on the insert card. Dimensional analysis. intravenous (IV) push medications for children (Chapter 14).com 08/11/11 6:21 PM .Preface ix drugs. easy-to-follow manner. Chapter 6 presents approximate system equivalents and shows how to convert from one unit of measurement to another. using a colon or fraction format. Unit 2 explains measurement systems. Unit 3. forming a foundation for understanding the complex dosage calculations presented in Unit 3. and household units of measurement are given in Chapter 5. Chapters 8 and 9 cover oral and parenteral dosage calculations. Sample dosage questions specific to a drug label are used as examples. (021) 66485438 66485457 LWBK914-FM_pi-xvi. The metric system. problemsolving methodology is presented in a simple. A step-by-step approach is used. Emphasis on the apothecary system has been limited because of the need to minimize use of the system. The intravenous therapy content has been expanded in Chapter 10. The unit begins with a detailed description of how to read and interpret medication labels in Chapter 7. The preassessment test should be completed before beginning.ketabpezeshki. presented in detail in Chapter 8. Chapter 4 shows how to set up a ratio and proportion and solve for x. Throughout this unit. to provide quick and easy access when calculating drug dosage problems. the apothecary system. Drug-related word problems are used as contemporary examples. Enrichment information can be found in the appendices. including pediatric considerations. • The reference insert card has been updated with dosage calculation formulas. Answer Keys are available to check your work. charts. 300 new practice problems have been put online.ketabpezeshki. Throughout the chapters. as one of three ways to calculate dosages. along with ratio and proportion and the Formula Method.lww. • Pictures. New Content in This Edition • Practice Problems on thePoint.x Preface Special Features A pocket-size laminated insert card containing approximate system equivalents and conversion formulas is included for quick and easy access when calculating drug dosage problems. and tables have been updated. Revised and Expanded Chapters • Chapter 5: The Metric. and the content related to apothecary equivalents has been decreased.indd x www. Use the code in the front of your book to access these online practice problems. This method is used consistently throughout the book. you will be referred to http://thePoint.com 08/11/11 6:21 PM . In an effort to maintain the size of the book yet meet the student and faculty requests for more questions. • Dimensional analysis (DA) has been expanded in Chapter 8 to show the different ways that the formula can be used. • New content has been added for IV push medications. and Apothecary Systems of Measurement (021) 66485438 66485457 LWBK914-FM_pi-xvi. This popular feature has been retained in this edition. along with the Critical Thinking Checks—questions designed to help you analyze the results of your answer to a dosage problem. Household. • Learning objectives have been expanded in every chapter to help guide you in your learning. They appear frequently throughout the book.com/Boyer8e to access these additional questions. As you use this book. phd (021) 66485438 66485457 LWBK914-FM_pi-xvi.indd xi www. as a result. It is our inherent responsibility as nurses to ensure that every patient entrusted to our care receives the correct dosage of medication delivered in the most appropriate way.edu with your comments and/or suggestions for improvement.com 08/11/11 6:21 PM .ketabpezeshki. It is my hope that its use will help nurses to calculate dosages accurately and.Preface xi • • • • • • Chapter 8: Oral Dosage Calculations Chapter 9: Parenteral Dosage Calculations Chapter 10: Intravenous Therapy Chapter 11: Intravenous Therapies: Critical Care Applications Chapter 12: Insulin Chapter 13: Heparin Preparation and Dosage Calculations: Subcutaneous and Intravenous • Chapter 14: Pediatric Dosage Calculations and Intravenous Therapy • Chapter 15: Solutions and Drug Reconstitution Math for Nurses was written for all nurses who administer drugs. to improve the accuracy of drug delivery. Mary Jo Boyer. easy. please email me at mboyer@ dccc. rn. It is intended as a quick. and readily accessible guide when dosage calculations are required. or 1. 100.indd xii www.com 08/11/11 6:21 PM .000 59 Change Fractions to Decimals 61 Change Decimals to Fractions 63 Round Off Decimals 64 End of Chapter Review 66 4 Percents.ketabpezeshki. and Proportion 69 Percent 70 Fractions and Percents 71 Decimals and Percents 74 Ratio and Proportion 78 Use of Ratio and Proportion: Solving for x 81 End of Chapter Review 90 End of Unit 1 Review 95 xii (021) 66485438 66485457 LWBK914-FM_pi-xvi. or 1. Ratio. 100.000 56 Divide of Decimals 57 Division by 10.Contents UNIT 1 Basic Mathematics Review and Refresher 1 1 Preassessment Test: Mathematics Skills Review 3 2 Fractions 9 The Denominator of a Fraction 10 The Numerator of a Fraction 11 Concept of Size 13 Types of Fractions and Value 15 Equivalent or Equal Fractions 16 Simplify or Reduce Fractions to Their Lowest Terms 19 Find the Least Common Denominator 21 Conversion 22 Addition of Fractions 26 Addition of Mixed Numbers 30 Subtraction of Fractions 31 Subtraction of Mixed Numbers 33 Multiplication of Fractions 38 Division of Fractions 40 End of Chapter Review 44 3 Decimals 47 Compare Decimal Values 51 Add of Decimals 52 Subtract of Decimals 53 Multiply of Decimals 55 Multiplication by 10. and Apothecary Systems of Measurement 101 The Metric System 102 Meter—Length 104 Liter—Volume 104 Gram—Weight 104 The Apothecary System 105 Household Measurements 107 Converting Within the Same System: Metric System 111 Converting Within the Same System: Household and Apothecary 115 End of Chapter Review 118 6 Approximate Equivalents and System Conversions 121 Dosage Calculations: Converting Between Systems 122 End of Chapter Review 127 End of Unit 2 Review 130 UNIT 3 Dosage Calculations 133 7 Medication Labels 136 Reading and Interpreting a Drug Label 137 End of Chapter Review 144 8 Oral Dosage Calculations 147 Calculating Oral Dosages 149 Dosage Calculations for Medications in the Same System and the Same Unit of Measurement 157 Dosage Calculations for Medications in the Same System but with Different Units of Measurement 161 Dosage Calculations for Medications in Different Systems 164 End of Chapter Review 169 9 Parenteral Dosage Calculations 172 Packaging. Household.Contents xiii UNIT 2 Measurement Systems 99 5 The Metric.com 08/11/11 6:21 PM . Syringes. and Needles 173 Types of Injections 176 Dosage Calculations for Medications in the Same System and the Same Unit of Measurement 177 Dosage Calculations for Medications in the Same System but Having Different Units of Measurement 181 (021) 66485438 66485457 LWBK914-FM_pi-xvi.ketabpezeshki.indd xiii www. the Formula Method.indd xiv www. or Dimensional Analysis 221 Calculate Dosage. per Hour or per Minute.xiv Contents Dosage Calculations for Medications in Different Systems 182 Penicillin 184 End of Chapter Review 186 10 Intravenous Therapy 191 Key Terms 192 Intravenous Fluids 193 Intravenous Infusion Sets and Lines 195 Infusion Devices 195 Calculate Intravenous Fluid Administration 197 Calculate Infusion Time in Hours and Minutes 198 Calculate Flow Rate in Milliliters per Hour for Gravity or Pump Infusions 199 Calculate Drip Rate or Drops per Minute 202 Constant Factors 207 Intermittent Intravenous Administration 208 End of Chapter Review 216 11 Intravenous Therapies: Critical Care Applications 219 Calculate Flow Rate (mL per hr) When Dosage Is Known. When Flow Rate Is Known 226 Titrate IV Fluids 231 End of Chapter Review 233 12 Insulin 238 Insulin Preparation 239 Types of Insulin 240 Insulin Delivery Devices 242 Insulin Administration 246 Preparing Insulin for Injection 247 Mixing Two Types of Insulin in One Syringe 248 Continuous Intravenous Insulin Infusion 252 End of Chapter Review 254 13 Heparin Preparation and Dosage Calculations: Subcutaneous and Intravenous 258 Heparin for Subcutaneous Injection 261 Heparin for Intravenous Infusion 264 Calculate Heparin Flow Rate (mL/hr) When Units of Heparin per Hour Are Ordered 265 Calculate Heparin Dosage (units per hr) When Heparin Is Ordered in Milliliters per Hour 268 (021) 66485438 66485457 LWBK914-FM_pi-xvi. Use Ratio and Proportion.com 08/11/11 6:21 PM .ketabpezeshki. Subcutaneous Injections 372 F.indd xv www. Roman Numerals 361 B. Nursing Considerations for Critical Care Drug Administration 383 (021) 66485438 66485457 LWBK914-FM_pi-xvi.com 08/11/11 6:21 PM . Nursing Concerns for Pediatric Drug Administration 381 J.Contents xv Heparin Administration Based on Weight 269 Weight-Based Heparin Protocol 271 End of Chapter Review 276 14 Pediatric Dosage Calculations and Intravenous Therapy 280 Weight Conversions 284 Estimate Safe Total Daily Dosage 287 Calculate Oral and Parenteral Dosages Based on Body Weight (mg per kg) 289 Estimate Body Surface Area 293 Dosage Calculations Based on Body Surface Area 294 Calculate Intravenous Flow Rate 300 Calculate Intermittent Intravenous Medication Administration (Intravenous Piggyback: IVPB) 302 Calculate IV Push Medications 308 End of Chapter Review 310 15 Solutions and Drug Reconstitution 317 Reconstitution: Preparing Injection Packaged as Powders 319 Preparing an Oral or Enteral Feeding 324 Preparing a Topical Irrigating Solution 326 End of Chapter Review 327 End of Unit 3 Review 329 Answers 337 Appendices A.ketabpezeshki. Intramuscular Injections 374 G. Rounding Off Decimals 364 C. Z-Track Injections 376 H. Intradermal Injections 370 E. Abbreviations for Drug Preparation and Administration 366 D. Pediatric Intramuscular Injections 379 I. Needleless Intravenous System 388 M.com 08/11/11 6:21 PM .indd xvi www. Nursing Concerns for Geriatric Drug Administration 385 L. Temperature Conversions: Fahrenheit and Celsius Scales 390 Index 393 (021) 66485438 66485457 LWBK914-FM_pi-xvi.ketabpezeshki.xvi Contents K. indd 1 www.1 Basic Mathematics Review and Refresher (021) 66485438 66485457 LWBK914-C01_p01-08.ketabpezeshki.com 07/11/11 2:11 PM . percents. The ability to solve for x assumes a basic mastery of fractions and decimals. This process is presented in a step-by-step format in Chapter 4.com 07/11/11 2:11 PM . subtraction. multiplication. and ratio-proportion. and division for fractions and decimals is provided in Chapters 2 and 3 so you can review this material. In order to accurately calculate dosage problems. 2 (021) 66485438 66485457 LWBK914-C01_p01-08.T his unit presents a basic review of fractions. Therefore. An end-of-unit review is provided to reinforce the rules. a brief discussion of addition. you need to be able to transcribe a word problem into a mathematical equation. decimals.ketabpezeshki.indd 2 www. ketabpezeshki. This pretest will help you understand your ability to solve fraction. Answers are listed in the back of the book. please review the corresponding section in Unit I. A score of 90% or greater means that you have mastered the knowledge necessary to proceed directly to Unit II.com 07/11/11 2:11 PM . each worth one point. Begin by setting aside 1 hour. If you need to review Roman numerals and associated Arabic 3 (021) 66485438 66485457 LWBK914-C01_p01-08. and percentage problems and determine the value of an unknown (x) using the ratio-proportion. decimal. There are 100 questions.indd 3 www. You will need scrap paper. If an answer is incorrect. Take time to work out your answers and avoid careless mistakes.CHAPTER 1 Preassessment Test: MATHEMATICS SKILLS REVIEW B asic math skills are needed to calculate most dosage and solution problems encountered in clinical practice. xv 7. Reduce to lowest terms. 6. 13 3.indd 4 www.ketabpezeshki. please refer to Appendix A before beginning the pretest. 8 2. 1 3 + = 5 10 14. LXV 9. Write the following Arabic numbers as Roman numerals. 1 1 or 3 6 16. 4 2 – = 6 5 Choose the fraction that has the largest value. 15. 1 1 or 150 200 17. 11. 1.UNIT 1 4 Basic Mathematics Review and Refresher equivalents. xix Add or subtract the following fractions. 10 4. 1 3 or 2 4 (021) 66485438 66485457 LWBK914-C01_p01-08. 51 Write the following Roman numerals as Arabic numbers. 1 1 or 100 150 18. 1 1 + = 2 8 12.com 07/11/11 2:11 PM . 3 1 – = 4 4 13. 37 5. ix 10. xvi 8. Reduce to lowest terms.CHAPTER 1 Preassessment Test 5 Multiply or divide the following fractions. 16 13 Change the following fractions to decimals. 25. 4 ÷ 11 = 5 8 ×3 = 7 Change the following mixed numbers to improper fractions.indd 5 36. 35. 1 3 × = 2 4 2 5 20. 2 × 3 = 5 10 21. 2 5 www. Remember to place a 0 before the decimal point when the decimal is less than (⬍) one. Reduce to lowest terms. 1 1 ×2 = 150 2 24.com 07/11/11 2:11 PM . 8 1 7 Change these improper fractions to whole or mixed numbers. 1 3 (021) 66485438 66485457 LWBK914-C01_p01-08. 3 ÷ = 2 7 23. 35 11 34. 1 1 ÷ = 4 3 1 4 22.ketabpezeshki. 120 40 32. 2 4 5 29. 10 4 9 28. 19. 31. 146 36 33. 27. 1 ÷6= 8 2 26. 6 3 4 30. as indicated. 3 8 Basic Mathematics Review and Refresher 38. 0.3 Change the following decimals to fractions. 0. 6 0.2 : 14 :: x : 10 54.14 0. 7.125 2 45.45 51. 0.ketabpezeshki. 0. 6 8.33 50. 0.60 Solve for the value of x in the following ratio and proportion problems. 6 : 2 :: 8 : x 56. 0.13 42. 3. 4.com 07/11/11 2:11 PM .6 UNIT 1 37.2 : x 55. 39.80 49.75 52.71 0.indd 6 www.36 1. 5 : 20 :: x : 40 (021) 66485438 66485457 LWBK914-C01_p01-08. Reduce to lowest terms. 0.45 40. 2.82 2. 21. 3 4 Add or subtract the following decimals.25 48.01 Multiply or divide the following decimals.13 44. as indicated.8 : 4 :: 3.3 46.6 0. 0. 47. 43. as indicated. 53.29 41. 0. 0.75% 82. 4.60 : 3 5 61.36% 81.01 73. 25% 76. 0. 12 : x :: 8 : 16 60.36 5 40 65.indd 7 www. 4 16 71. 15% 79.ketabpezeshki. 1.07 66. 0. 60/100 72.CHAPTER 1 Preassessment Test 7 57. 67. x : 8 :: 1 : 10 4 Change the following fractions and decimals to percentages.98 74. 1.com 07/11/11 2:11 PM . 8 56 Change the following percents to decimals. 1 1 : :: :3 5 20 59. x : 4 :: 0. 8.103 68. 0. 120 100 70. 0. 80% 78. 0. 1. 40% 77. 0.30% (021) 66485438 66485457 LWBK914-C01_p01-08. 1 5 64. 63.25 : 200 :: x : 600 58.3 : 12 :: x : 36 62. 75.8% 80.83 69. 99. 100. 20 is 80% of 88. What % of 60 is 12? 90.50 www.5% of 200 85. 15 is 30% of 92. 60 is 50% of Write each of the following measures in its related equivalency.45% 98.ketabpezeshki. (021) 66485438 66485457 LWBK914-C01_p01-08.6% of 180 86.com 07/11/11 2:11 PM .indd 8 1 : 100 1 120 0.UNIT 1 8 Basic Mathematics Review and Refresher Solve the following percent equations. 4. 0. 0. 30% of 60 84. 83. 25% 94. 1 : 30 95. 30 is 75% of 87.05 1 150 96. Reduce to lowest terms. What % of 80 is 20? 89. 97. Percent Colon Ratio Common Fractions Decimal 93. 0. What % of 72 is 18? 91. • Distinguish between the four types of fractions. multiply. A fraction is a part or piece of a whole number that indicates division of that number into equal units or parts. A fraction is written with one number over 9 (021) 66485438 66485457 LWBK914-C02_p09-46. and the fraction value relative to the value of one (1). • Add. and divide fractions. • Convert fractions and reduce them to their lowest terms.CHAPTER 2 Fractions LEARNING OBJECTIVES After completing this chapter. the concept of size. you should be able to: • Understand the concept of a fraction—the number of parts to a whole.com 07/11/11 2:11 PM . T he term fraction means a type of division. subtract.indd 9 www.ketabpezeshki. R U L E The denominator refers to the total number of equal parts and is the number on the bottom of the fraction. the denominator is 8.1. 2/5. as well as in a variety of reports. for example.ketabpezeshki. The Denominator of a Fraction The denominator of a fraction refers to the total number of equal parts into which the whole has been divided. They are divided into equal parts (4 and 8). If you divide the circle into eight equal parts. the smaller the value of the equal parts (or fraction) of the whole. the total number of parts (4) that you are working with is the bottom number of the fraction and is called the denominator. Each part of the circle (1) is a fraction or piece of the whole (1/4 or 1/8). The number above the line (numerator) is divided by the number under the line (denominator). medical orders.indd 10 www. (021) 66485438 66485457 LWBK914-C02_p09-46. See Figure 2. The larger the number in the denominator. it can be read as numerator (1) divided by denominator (4).UNIT 1 Basic Mathematics Review and Refresher 10 another. and documents used in health care. Because the fraction (1/4) represents division. Look at the circles in Figure 2. If you divide a circle into four equal parts. therefore. The denominator is also called the divisor.com 07/11/11 2:12 PM . 1/4. the line between the numbers is a division sign.1. You need to know how to calculate dosage problems with fractions because they are used in apothecary and household measures. ketabpezeshki. each part (1) that you are considering is the top number of the fraction and is called the numerator.indd 11 www.CHAPTER 2 1 — 8 1 — 8 1 — 4 1 — 4 1 — 4 1 — 4 1 — 8 1 — 8 1 — 8 1 — 8 Fractions 11 1 — 8 1 — 8 FIGURE 2. If you divide the circle into eight equal parts. The Numerator of a Fraction The numerator of a fraction tells you how many parts of the whole are being considered.com 07/11/11 2:12 PM .1 Two circles: the whole divided into equal parts. (021) 66485438 66485457 LWBK914-C02_p09-46. If you divide a circle into four equal parts. ketabpezeshki. The denominator is _____.UNIT 1 Basic Mathematics Review and Refresher 12 and you are considering three parts. 3. each worth _____. R U L E The numerator refers to a part of the whole that is being considered and is the number on the top of the fraction. 3/4 means that you have _____ equal parts. 1. In the circle examples in Figure 2. For the fraction 3/8. The denominator is _______. which is _____.1. 9/10 means that you have _____ equal parts. The larger the number in the numerator. three parts of the total (8) are being considered. 4/5 means that you have _____ equal parts. 2.com 07/11/11 2:12 PM . each worth ⅛. Fill in the blanks for the rest. the more parts of the whole that are being considered. Fractio r n 1 1 numerat r or or = = “divided by” 4 8 denominator PRACTICE PROBLEMS Use the first problem as an example. each worth _____. The numerator is _____ divided by the denominator. The numerator is also called the dividend. The numerator is 7 divided by the denominator. 7/8 means that you have 7 equal parts.indd 12 www. each worth _____. 4. the numerator is three (3). which is 8. (021) 66485438 66485457 LWBK914-C02_p09-46. the numerator in both is 1 and the denominator is either 4 or 8. Therefore. (021) 66485438 66485457 LWBK914-C02_p09-46. Look at Figure 2. you will notice that the circle that is divided into eighths has smaller portions than the circle that is divided into fourths. the larger the number in the denominator. For example: 1 1 is larg a er than 2 4 1 1 is larg a er than 8 16 1 1 is larg a er than 9 10 R U L E When the denominators are the same. the larger the value of the parts of the whole. that is. the smaller the value of the parts (or fraction) of the whole. As you look at the circles. the larger the number in the numerator. the smaller the fraction or parts of the whole. the larger the number or value in the denominator.CHAPTER 2 Fractions 13 Concept of Size R U L E When the numerators are the same.com 07/11/11 2:12 PM .1. This is an important concept to understand. Even though 1/8 has a larger denominator (8) than does 1/4 (4).ketabpezeshki. The reason is that the value of each part of the fraction 1/8 is less than the value of each part of the fraction 1/4. it is a smaller fraction.indd 13 www. which illustrates two circles: one is divided into fourths. and one is divided into eighths. 2 Two circles: shaded areas indicate larger sizes.14 UNIT 1 Basic Mathematics Review and Refresher 1/4 1/4 1/4 1/4 1/8 1/8 1/8 1/8 1/8 1/8 1/8 1/8 FIGURE 2. 1/8 or 1/16 _________ 3.2. The shaded area in the bottom circle shows that 5/8 is larger than 3/8. 1/2 or 1/4 _________ 2. 3/15 or 8/15 ________ (021) 66485438 66485457 LWBK914-C02_p09-46. 1.com 07/11/11 2:12 PM .indd 14 www. PRACTICE PROBLEMS Indicate which fractions are larger.ketabpezeshki. 2/5 or 4/5 __________ 5. Look at Figure 2. The shaded area in the top circle shows that 3/4 is larger than 1/4. 1/6 or 4/6 _________ 6. 1/9 or 1/10 ________ 4. < 1. Equal to One (1). That is. and Greater Than One (⬎1) Common fractions can be divided into four groups: proper fractions.com 07/11/11 2:12 PM . and complex fractions. = 1. These fractions are called improper fractions. list the fraction with the smallest value first.indd 15 www. =1 1 3 25 (021) 66485438 66485457 LWBK914-C02_p09-46.CHAPTER 2 Fractions 15 Arrange the following fractions in order of size. then the next larger fraction. and so on until you end with the largest-valued fraction last. <1 4 8 10 R U L E If the numerator and denominator are equal to each other. These fractions are called proper fractions. the fraction value is equal to one. 1 1 9 12 1 3 1 1 7 150 1 1 25 100 1 300 0 1 75 Types of Fractions and Value Fractions That Are Less Than One (⬍1). the fraction value is less than one. improper fractions.ketabpezeshki. R U L E If the numerator is less than the denominator. EXAMPLES: 1 3 25 = 1. EXAMPLES: 3 7 9 < 1. mixed numbers. EXAMPLES: 1 3 8 2 < 1.com 07/11/11 2:12 PM . These fractions are called complex fractions. 3 > 1. EXAMPLES: 2 5 1 = 2 > 1. or greater than one.ketabpezeshki. These fractions are mixed numbers. equal to. the value may be less than. = 1 >1 1 4 4 R U L E If a fraction and a whole number are written together. These fractions are also called improper fractions.indd 16 www. 12 = 1. 14 > 1 5 1 2 20 3 Equivalent or Equal Fractions Change Fractions to Equivalent or Equal Fractions When you are working problems with fractions.UNIT 1 Basic Mathematics Review and Refresher 16 R U L E If the numerator is greater than the denominator. the fraction value is always greater than one. EXAMPLES: 1 3 4 1 > 1. the fraction value is greater than one. it is sometimes necessary to change a fraction to a different (021) 66485438 66485457 LWBK914-C02_p09-46. 5 > 1 2 4 5 R U L E If a fraction includes a combination of whole numbers and proper and improper fractions in both the numerator and the denominator. ⎛ 2 ÷ 2 = 1 ⎞⎟ ⎜⎜ ⎟ ⎜⎝ 4 ÷ 2 = 2 ⎟⎟⎠ It is important to remember that you can change the numerator and the denominator of a fraction and the value of the fraction will be unchanged as long as you follow the following rule: R U L E When changing a fraction yet keeping the same equivalent value.com 07/11/11 2:12 PM .CHAPTER 2 Fractions 17 but equivalent fraction to make the math problem easier to calculate. you must do the same thing (multiply or divide by the same number) to the numerator and to the denominator. You can make a new fraction that has the same value by either multiplying or dividing both the numerator and the denominator by the same number. EXAMPLES: 2 4 3 can be changed to 6 by multiplying both the numerator and the denominator by 2. (021) 66485438 66485457 LWBK914-C02_p09-46. For example.ketabpezeshki. Look at the following examples. ⎛ 2 × 2 = 4 ⎞⎟ ⎜⎜ ⎟ ⎜⎝ 3 × 2 = 6 ⎟⎟⎠ 2 1 4 can be changed to 2 by dividing both the numerator and the denominator by 2.indd 17 www. it may be necessary to change 2/4 to 1/2 or 2/3 to 4/6. 18 UNIT 1 Basic Mathematics Review and Refresher EXAMPLES: 4 8 To change the fraction to .indd 18 www. 3/5 is equivalent to: 6/15 or 9/10 or 12/20 2. then the product of 4 ⫻ 10 will equal the product of 5 ⫻ 8. 4/8 is equivalent to: 8/24 or 12/16 or 20/40 3. multiply the opposite numerators and denominators. 4 ⫻ 10 ⫽ 40 and 5 ⫻ 8 ⫽ 40 PRACTICE PROBLEMS Circle the correct answer. ⎛ 4 × 2 = 8 ⎞⎟ ⎜⎜ ⎟ ⎜⎝ 5 × 2 = 10 ⎟⎟⎠ 4 8 has the same value as . For example. multiply 5 10 4 ⫻ 2 and 5 ⫻ 2. if 4/5 ⫽ 8/10. 6/12 is equivalent to: 2/4 or 3/5 or 12/36 4.com 07/11/11 2:12 PM .ketabpezeshki. 1. 10/16 is equivalent to: 20/48 or 5/8 or 30/32 (021) 66485438 66485457 LWBK914-C02_p09-46. ⎛ 4 ÷ 4 = 1 ⎞⎟ ⎜⎜ ⎟ ⎜⎝16 ÷ 4 = 4 ⎟⎟⎠ To determine that both fractions have equal value. 5 10 4 1 To change the fraction to . divide 4 16 4 by 4 and 16 by 4. indd 19 www. or reduced to the lowest terms. This means that the numerator and the denominator are the smallest numbers that can still represent the fraction or piece of the whole. it is easier to work with fractions that have been simplified.CHAPTER 2 Fractions 19 5. For example. R U L E To reduce a fraction to its lowest terms: Divide both the numerator and the denominator by the largest number that can go evenly into both. 8/144 is equivalent to: 2/36 or 4/23 or 1/18 Simplify or Reduce Fractions to Their Lowest Terms When calculating dosages. 18/30 is equivalent to: 3/15 or 9/10 or 6/10 7. 14/56 is equivalent to: 2/6 or 1/4 or 7/8 10. It is important to know how to reduce (or simplify) a fraction. 12/20 is equivalent to: 3/5 or 6/5 or 4/10 6. 9/54 is equivalent to: 3/16 or 1/6 or 1/8 8.ketabpezeshki. 15/90 is equivalent to: 1/6 or 3/8 or 5/14 9. 4/8 can be reduced to 1/2. Remember: You may have to reduce several times. The following rule outlines the steps for reducing a fraction to its lowest terms. 4/10 can be reduced to 2/5.com 07/11/11 2:12 PM . (021) 66485438 66485457 LWBK914-C02_p09-46. UNIT 1 Basic Mathematics Review and Refresher 20 EXAMPLES: 9 Reduce the fraction to its lowest 18 terms. Reduce: Reduce: 6 3 can be reduced to 10 5 by dividing both the numerator and the denominator by 2. 4 PRACTICE PROBLEMS Reduce the following fractions to their lowest terms: 1. Then can be reduced again to 44 1 by dividing by 11. 4 336 6. 6 36 3.indd 20 www. 3 12 7. 35 105 8. 8 4 48 2. 63 105 (021) 66485438 66485457 LWBK914-C02_p09-46. 33 11 can be reduced to 132 44 by dividing both the numerator and the denominator 11 by 3. ⎛ 9 ÷ 9 = 1 ⎞⎟ ⎜⎜ ⎟ ⎜⎝18 ÷ 9 = 2 ⎟⎟⎠ The largest number that can be used to divide both the numerator (9) and the denominator (18) is 9. 10 60 5.com 07/11/11 2:12 PM . 2 18 4.ketabpezeshki. CHAPTER 2 Fractions 21 Find the Least Common Denominator R U L E To find the least common denominator (LCD): Find the smallest number that is easily divided by both denominators and then change the fraction to equivalent fractions. 1 5 3 12 = = 4 20 5 20 • Add the new numerators and place that number over the new LCD.com 07/11/11 2:12 PM . that number now becomes your new LCD. When beginning.ketabpezeshki. EXAMPLE: 1 3 + 4 5 • Find the smallest number (LCD) that all the denominators can be divided evenly into. Divide the LCD by the denominator and then multiply that number by the numerator. Add 1 3 + The LCD ⫽ 20 4 5 • Change the unlike fractions to equivalent or equal fractions using the LCD. 5 12 17 + = 20 20 20 ANSWER: (021) 66485438 66485457 LWBK914-C02_p09-46. first see if any of the denominators can be easily divided by each of the other denominators. each with the same denominator. If so.indd 21 17 20 www. Remember: least common denominator ⫽ smallest number. EXAMPLE: Add 1 5 + 3 6 • Change The LCD ⫽ 6 1 2 to 3 6 5 5 stays 6 6 and • Add the new numerators and place that number over the new LCD. If you get a final answer that (021) 66485438 66485457 LWBK914-C02_p09-46.ketabpezeshki. A mixed number (1 1/4) can be changed to an improper fraction (5/4) and an improper fraction (3/2) can be changed to a mixed number (1 1/2). 7 1 is changed to 1 6 6 ANSWER: 1 1 6 Conversion Convert Mixed Numbers and Improper Fractions You need to know how to convert a variety of fractions to make drug dosage calculations easier.com 07/11/11 2:12 PM .indd 22 www. if necessary. 2+5= 7 7 6 • Change the improper fraction to a mixed number.22 UNIT 1 Basic Mathematics Review and Refresher • Reduce and change any improper fraction to a mixed number. EXAMPLE: Change 2 2 3 to an improper fraction. convert it to a mixed number. 4 3 =4 2=8 4 8+3 11 The answer (11) becomes the new numerator of the new single fraction. follow these rules.com 07/11/11 2:12 PM .ketabpezeshki.” To understand how to convert fractions. Change a Mixed Number to an Improper Fraction R U L E To change a mixed number to an improper fraction: Multiply the denominator by the whole number and then add the numerator to that sum. For example. it is better to say “I have 1 1/4 apples” than to say “I have 5/4 apples.indd 23 becomes the improper www. 2 3 11 = 4 4 3 The mixed number 2 4 11 fraction .CHAPTER 2 Fractions 23 is an improper fraction. The denominator in the original stays the same. 4 (021) 66485438 66485457 LWBK914-C02_p09-46. 32 2 3 6. 18 1 2 8. 8 3 5 4.ketabpezeshki. 5 2 5 3 9 10.com 07/11/11 2:12 PM .UNIT 1 Basic Mathematics Review and Refresher 24 PRACTICE PROBLEMS Change the following mixed numbers to improper fractions: 1. 6 7 8 3. (021) 66485438 66485457 LWBK914-C02_p09-46. 21 7.indd 24 www. 15 1 9 3 4 5. 5 9 12 2. The quotient becomes the whole number of the mixed number. 11 1 6 Change an Improper Fraction to a Mixed Number R U L E To change an improper fraction to a mixed or whole number: Divide the numerator by the denominator and then use the leftover numbers as the new numerator and the new denominator of the mixed number. 6 9. 13 ⫼ 7 ⫽ 1 (new whole number) The remainder. 7 The number that you get (1) when you divide the numerator (13) by the denominator (7) becomes the whole number of the mixed number. 13 ÷ 7 = 1 6 ? The original denominator of the improper fraction (7) becomes the denominator of the fraction of the mixed number.com 07/11/11 2:12 PM . ANSWER: 1 6 7 PRACTICE PROBLEMS Change the following improper fractions to mixed numbers: 1. becomes the numerator of the fraction that goes with the whole number to make it a mixed number.CHAPTER 2 EXAMPLE: Change Fractions 25 13 to a mixed number. 41 6 www.indd 25 2. 13 ÷ 7 = 1 6 7 Any remainder is reduced to the lowest terms. 30 4 (021) 66485438 66485457 LWBK914-C02_p09-46. or number that you have left over (6).ketabpezeshki. Add Fractions When the Denominators Are the Same R U L E To add fractions with the same denominators: Add the numerators and place the new sum over the similar denominator. 86 9 10. 68 9 4. EXAMPLE: Add (021) 66485438 66485457 LWBK914-C02_p09-46. 62 8 9.ketabpezeshki. 112 6 Addition of Fractions When fractions are added. only the numerators are added.com 07/11/11 2:12 PM . 86 20 8. Reduce to lowest terms and change to a mixed number if necessary. 40 15 7. 72 11 5. fractions can be added only when the denominators are the same.indd 26 1 3 + 5 5 www. no calculations are done on the denominators. Therefore.UNIT 1 Basic Mathematics Review and Refresher 26 3. 90 12 6. Denominators that are different (unlike) must be made the same. com 07/11/11 2:12 PM . r or 1 3 4 new numerat + = = 5 5 5 same denominator ANSWER: 4 5 ANSWER: 5 7 1 4 + 7 7 EXAMPLE: A d Ad Change: 1 4 1+ 4 5 + = = 7 7 7 r or 5 = new numerat 7 = same denominator 1 9 + 6 6 EXAMPLE: A d Ad Change: 1 9 1 + 9 10 + = = 6 6 6 r or 10 = new numerat 6 = same denominator 10 need to be reduced 6 (021) 66485438 66485457 LWBK914-C02_p09-46.indd 27 www. For example: 1 3 1+ 3 + = =4 5 5 • Place the new sum over the same denominator.ketabpezeshki.CHAPTER 2 Fractions 27 • Add the numerators. place the new sum over the LCD. 5 (new quotient) ⫻ 1 (numerator) = (021) 66485438 66485457 LWBK914-C02_p09-46. 1 = 4 20 20 ÷ 4 5 3 = 5 20 20 ÷ 5 4 • Take each new quotient and multiply it by the numerator of each fraction. and reduce to lowest terms. take each new quotient and multiply it by each numerator. add the numerators.UNIT 1 Basic Mathematics Review and Refresher 28 Reduce: 10 10 ÷ 2 5 = = = imprope r r ffrraction 6 6 ÷2 3 Change: 5 2 = 5 ÷ 3 = 1 = a mixed number 3 3 ANSWER: 1 2 3 Add Fractions When the Denominators Are Not the Same R U L E To add fractions when the denominators are not the same: Find the least common denominator (LCD) of each fraction.ketabpezeshki. EXAMPLE: Add 1 3 + 4 5 The LCD is 20 • Divide the LCD of 20 by the denominator of each fraction to get the new quotient.indd 28 5 20 www.com 07/11/11 2:12 PM . CHAPTER 2 Fractions 4 (new quotient) ⫻ 3 (numerator) = 29 12 20 • Add the new numerators.ketabpezeshki. 1 = 3 6 6÷3= 2 1= 2 5 = 6 6 6÷6=1 5= 5 • Add the new numerators.com 07/11/11 2:12 PM . Reduce to lowest terms. 7 1 should be changed to 1 . 5 12 17 + = 20 20 20 ANSWER: EXAMPLE: Add 17 20 1 5 + 3 6 The LCD is 6. 6 6 ANSWER: 1 (021) 66485438 66485457 LWBK914-C02_p09-46. 2 5 2+5 7 + = = 6 6 6 • Change any improper fraction to a mixed number. Place the new sum over the LCD.indd 29 1 6 www. 1 4 becomes 6 24 19 57 becomes 8 24 5 20 becomes 6 24 • Add the new numerators and place your answer over the LCD. add the new numerators. • Change the different fractions to fractions with the same denominator. change to similar fractions. and reduce to lowest terms.com 07/11/11 2:12 PM . use the LCD of 24. EXAMPLE: Add 1 3 5 +2 + 6 8 6 • Change the mixed number to an improper fraction. For the denominators of 6 and 8. 3 19 2 becomes 8 8 • Find the LCD.UNIT 1 Basic Mathematics Review and Refresher 30 Addition of Mixed Numbers R U L E To add fractions with a mixed number: Change any mixed number to an improper fraction.indd 30 = 81 24 www.ketabpezeshki. 4 + 57 + 20 (021) 66485438 66485457 LWBK914-C02_p09-46. find the LCD. a new fraction 6 3 = 2 6 ANSWER: (021) 66485438 66485457 LWBK914-C02_p09-46.ketabpezeshki. EXAMPLE: Subt u tract 5 3 − 6 6 • Subtr tract 5 3 5 − = 6 6 3 • Reduce 2 1 = .CHAPTER 2 Fractions 31 • Reduce to lowest terms and change to a mixed number. 81 27 3 = =3 24 8 8 ANSWER: 3 3 8 Subtraction of Fractions Fractions can be subtracted only when the denominators are the same because only the numerators are subtracted. Reduce to lowest terms. Denominators that are unlike must be made the same. Subtract Fractions When the Denominators Are the Same R U L E To subtract fractions when the denominators are the same.com 07/11/11 2:12 PM . only subtract the numerators.indd 31 1 3 www. both will be presented here briefly just in case the situation occurs. However.indd 32 www. EXAMPLE: Subtr tract 5 3 − 6 5 • Find the least common denominator. R U L E To subtract fractions when the denominators are not the same: Find the LCD. Reduce to lowest terms. a new fraction 8 ANSWER: Subtr tract EXAMPLE: • Reduce 7 3 4 − = 8 8 8 3 8 4 1 = .ketabpezeshki. and subtract the new numerators. a new fraction 8 2 ANSWER: 1 2 Subtract Fractions When the Denominators Are Not the Same You will probably never need to subtract fractions with different denominators or fractions with a mixed number to calculate dosage problems.com 07/11/11 2:12 PM . change to similar fractions. 5 3 − = 30 (LCD) 6 5 (021) 66485438 66485457 LWBK914-C02_p09-46.UNIT 1 Basic Mathematics Review and Refresher 32 EXAMPLE: Subtr tract 7 4 7 − = 8 8 4 = 3 8 3 . R U L E To subtract fractions with a mixed number: Change the mixed number to an improper fraction.CHAPTER 2 Fractions 33 • Change to similar or equal fractions. and reduce to lowest terms.ketabpezeshki. 5 25 becomes 6 30 3 18 becomes 5 30 • Subtract the new numerators and place your answer over the common denominator: 25 18 25 − 18 7 − = = 30 30 30 30 ANSWER: 7 30 Subtraction of Mixed Numbers There are two ways to subtract fractions with mixed numbers: Change the mixed number to an improper fraction or leave the mixed number as a mixed number. find the LCD. change to similar fractions.com 07/11/11 2:12 PM . (021) 66485438 66485457 LWBK914-C02_p09-46. subtract the new numerators. Refer back to pages 21–26.indd 33 www. indd 34 www.ketabpezeshki. 17 51 becomes 8 24 3 12 becomes 6 24 • Subtract the new numerators and place your answer over the common denominator: 51 12 51 − 12 39 − = = 24 24 24 24 • Reduce and change to a mixed number. if necessary. use the LCD of 24. find the LCD.com 07/11/11 2:12 PM . (021) 66485438 66485457 LWBK914-C02_p09-46. 39 13 5 becomes =1 24 8 8 ANSWER: 1 5 8 R U L E To subtract fractions with a mixed number: Leave the fraction as a mixed number. • Change to similar or equal fractions.UNIT 1 Basic Mathematics Review and Refresher 34 1 3 Subtract 2 − 8 6 EXAMPLE: 1 17 3 2 = − 8 8 6 • Find the LCD. subtract the numerators and the whole number. For the denominators 8 and 6. and reduce to lowest terms. change to the same denominator. Then subtract the whole numbers.com 07/11/11 2:12 PM . 2 3 27 =1 24 24 12 12 − =− 24 ____ 24 ____ 15 5 1 =1 24 8 ANSWER: 1 (021) 66485438 66485457 LWBK914-C02_p09-46. 1 3 2 becomes 2 8 24 3 12 becomes 6 24 • First. Note: To subtract the larger number (12) from the smaller number (3). For the denominators of 6 and 8.indd 35 5 8 www. from the whole number 2. Then add 24 ⫹ 3 ⫽ 27.ketabpezeshki. use the LCD of 24. you need to borrow 1. You can now subtract the smaller number (12) from the larger number (27). subtract the numerators. or 24/24.CHAPTER 2 EXAMPLE: Fractions 35 1 3 Subtract 2 − 8 6 • Find the LCD. a new numerator. com 07/11/11 2:12 PM . 7 3 + = 16 8 3. 5 8 13 + + = 20 20 20 6. 4 1 +3 = 6 8 4. 10. (021) 66485438 66485457 LWBK914-C02_p09-46.ketabpezeshki. 5 9 13 + + = 11 11 11 2.36 UNIT 1 Basic Mathematics Review and Refresher PRACTICE PROBLEMS Add and reduce. 9 +1= 19 7. 1.lww.indd 36 www. 1 2 + = 9 5 17 11 + = 24 12 4 1 2 + + = 5 10 3 Additional practice problems to enhance learning and facilitate chapter comprehension can be found at http://thePoint.com/Boyer8e. 10 + 9. 11 14 + = 15 45 5. 4 9 + = 7 14 8. indd 37 www. 3 2 − = 4 9 3 2 15. 3 1 − = 5 6 14. (021) 66485438 66485457 LWBK914-C02_p09-46.ketabpezeshki. 3 − 2 = 4 6 Additional practice problems to enhance learning and facilitate chapter comprehension can be found at http://thePoint. 6 − = 7 3 1 1 16.lww.CHAPTER 2 Fractions 37 Subtract and reduce.com/Boyer8e.com 07/11/11 2:12 PM . 8 4 − = 9 9 13. 6 3 − = 7 7 12. 11. and reduce the product to lowest terms. if you work the problem.indd 38 www. So.com 07/11/11 2:12 PM . Reducing can be done before multiplying to make calculations easier. you simplify the numbers before you multiply by reducing the numbers to their lowest terms.UNIT 1 Basic Mathematics Review and Refresher 38 Multiplication of Fractions Multiply a Fraction by Another Fraction R U L E To multiply fractions: Multiply the numerators. EXAMPLES: 3 2 3 2 6 1 × = = = 4 3 4 3 12 2 1 2 1 2 2 1 × = = = 2 3 2 3 6 3 This method of multiplying fractions is sometimes called the “long form.” With cancellation. it looks like this: 1 8 1 82 × = × 4 15 41 15 (021) 66485438 66485457 LWBK914-C02_p09-46.ketabpezeshki. multiply the denominators.” There is also a “shortcut” method for multiplying fractions. called “cancellation. The value stays the same. Look at the following example: EXAMPLE: 1 8 × 4 15 Cancellation can be used because the denominator of the first fraction (4) and the numerator of the second fraction (8) can both be divided by 4 and the value of the fraction does not change. Remember: When multiplying a fraction and a whole number. place a one (1) under the whole number so it is expressed as a fraction. indd 39 3 4 www.ketabpezeshki.CHAPTER 2 Fractions 39 Once you have canceled all the numbers and reduced them to the lowest terms. you can then multiply the new numerators and the new denominators to get your answer. always change the mixed number to an improper fraction before you work the problem. Remember the following rule. EXAMPLE: 1 1 1 × 2 2 Change: 1 3 1 to 2 2 Multiply: 3 1 3 × = 2 2 4 ANSWER: (021) 66485438 66485457 LWBK914-C02_p09-46.com 07/11/11 2:12 PM . 1 2 2 × = 1 15 15 ANSWER: 2 15 Multiply a Fraction by a Mixed Number When you multiply a fraction by a mixed number. R U L E To multiply a fraction by a mixed number: Change the mixed number to an improper fraction before you work the problem. multiply the fractions. With division of fractions. invert the divisor.indd 40 www. and reduce.com 07/11/11 2:12 PM . R U L E To divide fractions by another fraction: Write your problem as division.ketabpezeshki. the divisor (5/9) is always inverted (9/5) to change the math calculation to multiplication! The answer is called the quotient. (021) 66485438 66485457 LWBK914-C02_p09-46. The divisor is always to the right of the division sign.UNIT 1 Basic Mathematics Review and Refresher 40 EXAMPLE: 1 1 1 ×4 2 2 Change: 1 3 1 to 2 2 Change: 4 Multiply: 3 9 27 3 × = or 6 2 2 4 4 1 9 to 2 2 ANSWER: 6 3 4 Division of Fractions Divide a Fraction by Another Fraction Sometimes it is necessary to divide fractions in order to calculate a drug dosage. To divide fractions. follow this rule. the first fraction (dividend) is divided by the second fraction (divisor). In any problem. Divide 4 5 (dividend) ÷ (divisor) (di i r) = quotient 5 9 4 9 ⎛⎜ 5⎞ × ⎜inverted ⎟⎟⎟ 5 5 ⎜⎝ 9 ⎟⎠ • Multiply and reduce. (021) 66485438 66485457 LWBK914-C02_p09-46.com 07/11/11 2:12 PM .CHAPTER 2 EXAMPLE: Fractions 41 4 5 ÷ 5 9 • Write your problem as division and invert the divisor.ketabpezeshki. The problem now looks like this: 4 9 36 11 × = =1 5 5 25 25 EXAMPLE: 7 3 ÷ 8 5 Invert: 3 5 to 5 3 Multiply: 7 5 35 11 × = =1 8 3 24 24 ANSWER: 1 11 25 ANSWER: 1 11 24 Divide a Fraction by a Mixed Number R U L E To divide fractions that are mixed numbers: Change the mixed number to an improper fraction and reduce.indd 41 www. 42 UNIT 1 Basic Mathematics Review and Refresher EXAMPLE: 3 2 ÷1 6 5 Change: 2 7 1 to 5 5 Write: 3 7 ÷ 6 5 Invert: 7 5 to 5 7 Multiply: 3 5 15 × = 6 7 42 Reduce: 15 5 = 42 14 ANSWER: 5 14 PRACTICE PROBLEMS Multiply and Reduce 1.com 07/11/11 2:12 PM . 3. 3 × = 8 16 (021) 66485438 66485457 LWBK914-C02_p09-46.indd 42 6. 2 4 3 5.ketabpezeshki. 6 2 × = 16 5 4. 8 8 × = 15 12 2. 5 3 × = 9 7 7 1 × = 10 2 4 10 × = 7 11 www. 1 = 3 4 2 ÷ = 7 13 Additional practice problems to enhance learning and facilitate chapter comprehension can be found at http://thePoint.com/Boyer8e.ketabpezeshki.indd 43 www.lww.CHAPTER 2 Fractions 43 Divide and Reduce 7. 12 ÷ 12. 8 3 ÷ = 12 7 11. 6 2 ÷ = 13 5 10. (021) 66485438 66485457 LWBK914-C02_p09-46. 8 7 ÷ 15 = 10 8.com 07/11/11 2:12 PM . 3 1 ÷ = 4 9 9. indd 44 www.End of Chapter Review Change the fractions with different denominators to similar fractions by finding the least common denominator: 1.com 07/11/11 2:12 PM . 105 = 8 Change these mixed numbers to improper fractions: 7. 20 = 64 10. 26 = 4 6.ketabpezeshki. 5 20 Reduce these fractions to lowest terms: 3. 16 = 128 Change these improper fractions to mixed numbers: 5. 4 6 = 11 8. 2 3 . 5 7 2. 16 = 128 44 (021) 66485438 66485457 LWBK914-C02_p09-46. 9 2 = 23 Reduce these fractions to their lowest terms: 9. 27 = 162 4. 7 4 . 1 24. 2 × 3 = 7 8 5 3 × = 11 8 28.com 07/11/11 2:12 PM . Fractions 45 15 = 84 Add the following fractions: 13. 1 3 + = 9 4 5 3 16. 4 2 ×7 = 3 4 www. 19. 2 27.indd 45 9 1 × = 11 3 1 6 ×6 = 10 9 25. 5 3 + = 6 6 15. 3 1 − = 4 6 20. 7 = 63 12. 4 3 1 21. 6 1 × = 8 5 2 4 26. 6 + = 6 8 Subtract the following fractions: 17. (021) 66485438 66485457 LWBK914-C02_p09-46. 1 7 + = 9 9 14. 5 3 − = 12 12 18. 7 2 − = 9 9 6 3 − = 10 8 9 7 − = 12 24 Multiply the following fractions: 23. 6 − 4 = 8 4 22.CHAPTER 2 11.ketabpezeshki. 3 7 ÷ = 5 20 31. 8 1 ÷ = 9 27 32. 4 ÷ 8 = 9 www.indd 46 30. 16 ÷ 32 = 160 (021) 66485438 66485457 LWBK914-C02_p09-46. 7 2 ÷ 80 = 14 34.com 07/11/11 2:12 PM .ketabpezeshki. 6 5 15 ÷ = 12 24 33.46 UNIT 1 Basic Mathematics Review and Refresher Divide the following fractions: 29. com 07/11/11 2:12 PM . with a denominator that is any multiple of 47 (021) 66485438 66485457 LWBK914-C03_p47-68. • Change fractions to decimals and decimals to fractions. Therefore. A decimal is simply a fraction. you should be able to: • Understand the concept of a decimal. multiply. it is critical that you understand how to read decimals. subtract. written in a different format. M edication dosages and other health care measurements are usually prescribed in the metric measure. • Add.indd 47 www. A serious medication error can occur if the drug dosage written in a decimal format is misread. • Read. which is based on the decimal system.ketabpezeshki. and compare the value of decimals. and divide decimals. write.CHAPTER 3 Decimals LEARNING OBJECTIVES After completing this chapter. 5 4 3 2 Whole Numbers Value > 1 Decimal Point .000).000 0. 100. The decimal point (. and 1. Refer to Figure 3. R U L E Numbers to the right of the decimal point have a value less than 1. always add a zero (0) to the left of the decimal point to avoid errors when reading the decimal’s value. If there is no whole number before the decimal point.com 07/11/11 2:12 PM .004 1 place 2 places 3 places Tenths Hundredths Thousandths It is important to remember that numbers to the right of the decimal point have a value less than 1.1 and the following rule. Numbers to the left of the decimal point are whole numbers that have a value equal to or greater than 1. and numbers to the left of the decimal point have a value equal to or greater than 1. 1 1 2 3 4 5 Decimal Value < 1 FIGURE 3.) placement determines the decimal’s value. Reading decimals is easy once you understand the concept of decimal values relative to the placement of the decimal point and whole numbers. See the following examples: EXAMPLES: Fraction Decimal Position to the Right of Decimal Decimal Point Value 2/10 3/100 4/1.ketabpezeshki.1 Decimal values.UNIT 1 Basic Mathematics Review and Refresher 48 10 (10.03 0. (021) 66485438 66485457 LWBK914-C03_p47-68.2 0.indd 48 www. indd 49 6.004 6 . 0. EXAMPLES: (021) 66485438 66485457 LWBK914-C03_p47-68.2 is read as 2 tenths because the number 2 is one position to the right of the decimal point.150 is read as 15 hundredths because the zero after the 15 does not enhance its value.ketabpezeshki.CHAPTER 3 Decimals 49 R U L E To read decimals: Read the whole number(s) to the left of the decimal point first.” and then read the decimal fraction to the right of the decimal point. The zero (0) to the left of the decimal point is not read aloud. 2 three hundredths 5.03 is read as 3 hundredths because the number 3 is two positions to the right of the decimal point.com 07/11/11 2:12 PM .2 six and Read: www. 0 3 0 . 0.0 0 4 four thousandths five and two tenths 5 . 0.004 is read as 4 thousandths because the number 4 is three positions to the right of the decimal point. EXAMPLES: 0. read the decimal point as “and” or “point.03 0. and then write the decimal fraction. 20. Five and thirty-seven thousandths 10.025 8. Four tenths (021) 66485438 66485457 LWBK914-C03_p47-68. write the decimal point.com 07/11/11 2:12 PM .153 5. PRACTICE PROBLEMS Write the following decimals as you would read them: 1. 10. 125.indd 50 www.083 4. 0.0067 6.0007 3. Twenty thousandths 12. 0.UNIT 1 Basic Mathematics Review and Refresher 50 R U L E To write decimals: Write the whole number (write zero [0] before the decimal point if there is no whole number). Sixty-four and seven hundredths 11.0125 7. 0. 36.ketabpezeshki. 3.075 Write the following in decimal format: 9.001 2. Note: Zeros written at the end of the decimal fraction do not change the decimal’s value. Fifteen thousandths 16.1 mg of a drug. you wouldn’t give 0. This rule also applies to whole numbers. Eight and sixty-four thousandths 14. 0. EXAMPLES: 1. If a patient was prescribed 0.CHAPTER 3 Decimals 51 13.60 0. R U L E To compare decimal values: The decimal with the largest number in the column to the right of the decimal (tenth place) has the greater value.75 is greater than 0.75 is greater than 2. 4. One tenth Compare Decimal Values Understanding which decimals are larger or smaller helps prevent serious medication dosage errors.250 is greater than 0. 3.indd 51 www. If both are equal. then apply the rule to the next column (hundredth place). 2.125 1.2 mg. Thirty-three and seven tenths 15.25 2.ketabpezeshki.com 07/11/11 2:12 PM .36 is greater than 1.50 (021) 66485438 66485457 LWBK914-C03_p47-68. 25 0. • Add the decimals in the same manner as whole numbers are added.indd 52 www.75 2.80 Add of Decimals R U L E To add decimals: Place the decimals in a vertical column with the decimal points directly under one another and add zeros to balance the columns. 1.25 2.24 8 0. Start at the far right column.15 0. 0. 0.ketabpezeshki.5 3. 1.186 0. 2.921 3. Add the decimals in the same manner as whole numbers are added.UNIT 1 Basic Mathematics Review and Refresher 52 P R A C T I C E P R O B L E M S Select the decimal with the largest value.35 1.24 8. EXAMPLE: Add: 0.00 • Start with the far right column.50 3.175 0. and place the decimal in the answer under the aligned decimal points.40 2.30 1.75 4. (021) 66485438 66485457 LWBK914-C03_p47-68.com 07/11/11 2:12 PM . 74 EXAMPLE: Add: 3.9 4.ketabpezeshki.50 3.24 8.6 6. Subtract the decimals in the same manner as whole numbers are subtracted.74 ANSWER: 11. and place the decimal in the answer under the aligned decimal points. 0. (021) 66485438 66485457 LWBK914-C03_p47-68.com 07/11/11 2:12 PM .indd 53 www.6 EXAMPLE: Add: 6 2.8 1.00 11.7 8.9 4.7 3.8 1. Start at the far right column.CHAPTER 3 Decimals 53 • Place the decimal in the answer directly under aligned decimal points.6 10.0 2.4 Subtract of Decimals R U L E To subtract decimals: Place the decimals in a vertical column with the decimal points directly under one another and add zeros to balance the columns.4 ANSWER: 10.6 ANSWER: 8. 52 EXAMPLE: Subtract: 8.2 4.32 15.2 6.60 (021) 66485438 66485457 LWBK914-C03_p47-68.com 07/11/11 2:12 PM .00 from 13.60 13. Place the decimal point in the answer directly under the aligned decimal points.84 1.52 ANSWER: 15.00 5.ketabpezeshki.54 UNIT 1 Basic Mathematics Review and Refresher EXAMPLE: Subtract: 4.1 ANSWER: 2.1 EXAMPLE: Subtract: 1.2 4. 6.1 • Start with the far right column. • Subtract the decimals in the same manner as whole numbers are subtracted.indd 54 www.32 from 16.1 from 6.60 8.84 16.60 ANSWER: 5.1 2. EXAMPLE: Multiply: 6.0200 3.0114 ANSWER: 4. Write down the product without the decimal point.ketabpezeshki.indd 55 www.3 by 7. The major concern is placement of the decimal point in the product.02 7. multiply. (021) 66485438 66485457 LWBK914-C03_p47-68. Add zeros on the left if necessary.0114 Multiply of Decimals Multiplication of Decimal Numbers Multiplication of decimals is done using the same method as is used for multiplying whole numbers.com 07/11/11 2:12 PM .CHAPTER 3 EXAMPLE: Decimals 55 Subtract: 3.6 • Multiply the decimal numbers as you would multiply whole numbers. and record the product without decimal points. and use that number to place the decimal point in the product. R U L E To multiply decimals: Place the decimals in the same position as whole numbers.0086 4.0086 from 7.6 6.3 7. Count off the number of decimal places to the right of both numbers being multiplied. 88 Multiplication by 10. or 1.3 7.com 07/11/11 2:12 PM .12 (021) 66485438 66485457 LWBK914-C03_p47-68. 0. There is one zero in the multiplier of 10.3 7.6 378 441 4788 (product) • Count off the number of decimal places to the right of the decimals in the two numbers being multiplied. Move the decimal one place to the right for an answer of 7.712 10.000 Multiplying by 10. 100. See Table 3. Simply move the decimal point the same number of places to the right as there are zeros in the multiplier.000 is a fast and easy way to calculate dosage problems.indd 56 www.712 7. 6.1.ketabpezeshki.6 378 441 47. In this case.12.88 one place to right of decimal one place to right of decimal two places. 100.712 0. counting right to left ANSWER: 47. Count off the total number of places in the product. or 1.56 UNIT 1 Basic Mathematics Review and Refresher 6. EXAMPLE: 0. there are two places. 000. When you divide decimals. use the same method you would use to divide whole numbers.08 1. or 1.1 Multiplying by 10. Move the decimal three places to the right for an answer of 80. the most important thing to remember is movement and placement of the decimal point in the divisor (number divided by).ketabpezeshki.CHAPTER 3 Decimals 57 Table 3.000 Multiplier Move the Decimal to the Right Number of Zeros 10 100 1. dividend (number divided).indd 57 Dividend = Quo Q tient Divisor 64 =8 8 www.080 80 Divide of Decimals Division of Decimal Numbers To divide decimals. EXAMPLE: 0.000 1 2 3 1 place 2 places 3 places 0.08 0. Q tient Quo Divisor Dividend ) 8 8 64 ) (021) 66485438 66485457 LWBK914-C03_p47-68.000. and quotient (product).com 07/11/11 2:12 PM . 100. There are three zeros in the multiplier of 1. indd 58 www. and add a zero in front of the decimal point.UNIT 1 Basic Mathematics Review and Refresher 58 R U L E To divide a decimal by a whole number: Place the decimal point in the quotient directly above the decimal point in the dividend.1 (quotient) 5 25 5 25 5 5 ) ANSWER: 5.32) the same number of places (one) that you moved the decimal point in the divisor. Divide: 3. make 1. EXAMPLE: To divide 0.1 R U L E To divide a decimal by a decimal: Make the decimal number in the divisor a whole number first.2 16 3 ↑ 2 32 ) ANSWER: 0.ketabpezeshki. place the decimal point in the quotient directly above the decimal point in the dividend.6.2 by 16 .32 by 1.com 07/11/11 2:12 PM . EXAMPLE: 25.5 5 5. Move the decimal point in the dividend (0.2 (021) 66485438 66485457 LWBK914-C03_p47-68.6 a whole number (16) by moving the decimal point one place to the right. move the decimal point in the dividend the same number of places that you moved the decimal point in the divisor. 4 21. See Table 3.541 17. 100. 16.indd 59 www.1 4.009 18. or 1.09 10.27 1.8 2. or 1.64 (021) 66485438 66485457 LWBK914-C03_p47-68.009 PRACTICE PROBLEMS Add the following decimals (carry out to hundredths): 1.000 is fast and easy. or 1.CHAPTER 3 Decimals 59 Table 3.4 3.000 Divisor Number of Zeros 10 100 1.000 1 2 3 Move the Decimal to the Left 1 place 2 places 3 places Division by 10. EXAMPLE: 0.2 Dividing by 10.2.com 07/11/11 2:12 PM . 100.ketabpezeshki. 100.09 . Just move the decimal point the same number of places to the left as there are zeros in the divisor.000 Dividing by 10. 0. 0. 67. 0.009 0.009. Move the decimal one place to the left for an answer of 0. 4 2.19 3.89 7.65 15.ketabpezeshki.9 6. 15.86 10. 148.79 9.22 81.18 122. 16 9.8 16. 26.33 1.1 9.6 8. 366.0795 Subtract the following decimals (carry out to hundredths): 7.41 (021) 66485438 66485457 LWBK914-C03_p47-68.49 19.002 20. 1. 5.07 0. 19.16 56.65 100 17.34 Multiply the following decimals (carry out to hundredths): 13.46 1.16 18. 2.1 14.indd 60 www. 16. 10.97 12. 13 7. 107.01 18. 0. 54 7. 1.11 11.60 UNIT 1 Basic Mathematics Review and Refresher 5.com 07/11/11 2:12 PM .86 12. 4 1. 39.7 Additional practice problems to enhance learning and facilitate chapter comprehension can be found at http://thePoint. then work the division to three places.4 26.CHAPTER 3 Decimals 61 Divide the following decimals (carry out to hundredths): 21.8 0.indd 61 www.61 7.09 22. 41 4. 0.3 23.01 27.ketabpezeshki.000 24. the numerator of the fraction (1) is divided by the denominator (5). 98. Change Fractions to Decimals When changing a fraction to a decimal.lww.com/Boyer8e. If a numerator does not divide evenly into the denominator. 134 12.7 1.008 10 25.3 28. ) 1 = numerat r or becomes dividen e d=1 51 5 = denominator becomes divisor = 5 (021) 66485438 66485457 LWBK914-C03_p47-68.com 07/11/11 2:12 PM . 63. 99 7. 18. 0 ) ANSWER: 0.166 1 = 6 6 1. • Place a decimal point after the whole number in the dividend. Carry out to three places. • Divide number by denominator and add zeros.166 (021) 66485438 66485457 LWBK914-C03_p47-68. 02 1 = 5 5 1. place a decimal point after the whole number in the dividend. 5 • Rewrite the fraction in decimal format.ketabpezeshki.UNIT 1 Basic Mathematics Review and Refresher 62 R U L E To convert a fraction to a decimal: Rewrite the fraction in division format.2 EXAMPLE: Convert: 0. place the decimal point in the quotient directly above the decimal point in the dividend. add zeros.indd 62 www.com 07/11/11 2:12 PM .000 6 40 36 40 36 4 ) ANSWER: 0. if necessary. • Align decimal point in quotient. EXAMPLE: Change 1 to a decimal. and divide the number by the denominator. Add zeros. CHAPTER 3 EXAMPLE: Convert: ) 1 =1÷ 8 = 8 1 8 ) Decimals 63 0.00 8 20 20 ANSWER: 0.25 Change Decimals to Fractions R U L E To change a decimal to a fraction: Simply read the decimal and then write it as it sounds.ketabpezeshki. Reduce if necessary.125 EXAMPLE: Convert: ) ) 1 5 = =1÷ 4 = 4 1 20 4 0 25 4 1.com 07/11/11 2:12 PM .indd 63 75 100 75 3 to 100 4 www. Read 0. EXAMPLE: Change 0.75 as 75 hundredths Write as Reduce (021) 66485438 66485457 LWBK914-C03_p47-68.125 8 1.000 8 20 16 40 40 ANSWER: 0.75 to a fraction. Read 0. 8 64 3. 15 60 4. it is explained in Appendix B for those of you who wish to review the steps.5 as 5 tenths Write as Reduce 5 10 5 1 to 10 2 Round Off Decimals Most decimals are “rounded off” to the hundredth place to ensure accuracy of calculations.ketabpezeshki. 16 240 6. Because this process is done infrequently in the clinical setting.com 07/11/11 2:12 PM .5 to a fraction. 6 30 2. 12 180 5. 3 57 (021) 66485438 66485457 LWBK914-C03_p47-68. PRACTICE PROBLEMS Convert the following fractions to decimals: 1.indd 64 www.64 UNIT 1 Basic Mathematics Review and Refresher EXAMPLE: Change 0. (021) 66485438 66485457 LWBK914-C03_p47-68.412 10.125 Additional practice problems to enhance learning and facilitate chapter comprehension can be found at http://thePoint.03 11. 5. 0. 0.ketabpezeshki. 0. 12.indd 65 www.CHAPTER 3 Decimals 65 Convert the following decimals to fractions: 7.007 8. 0.com 07/11/11 2:12 PM .lww.93 9.com/Boyer8e.2 12. End of Chapter Review Write the following decimals as you would read them: 1.35 8. 16. 0.65 3. 0. Six and eight hundredths 6.1 9. 10. One hundred twenty-four and three tenths 7.23 66 (021) 66485438 66485457 LWBK914-C03_p47-68. 18.04 2. 7.008 4.ketabpezeshki. Sixteen and one thousandths Solve the following decimal problems: 8.9 Write the following decimals: 5.com 07/11/11 2:12 PM . 5.006 4.062 59.indd 66 www.2 10. 0.12 19. 2.610 10.com 07/11/11 2:12 PM .893 5.75 12 15.indd 67 12 84 www.4 3. 3 4 27. 23.45 (021) 66485438 66485457 LWBK914-C03_p47-68.88 18. 6 10 25.2 14.43 Convert the following fractions to decimals and decimals to fractions: 24.02 89.009 14.024 23.109 6.8 17.20 16.070 0.4 12.56 0.31 20.ketabpezeshki.1 21. 12. 0. 1.78 4. 0. 26. 12. 38. 18. 27.38 0.9 0. 15.05 8.3 13. 4.06 22. 12.CHAPTER 3 Decimals 67 11. 06 30. 0. 6. 32.68 UNIT 1 Basic Mathematics Review and Refresher 28. 8.com 07/11/11 2:12 PM . 8 20 31.75 29.8 34. 0.5 www.ketabpezeshki.indd 68 2 9 35. 1. 4 5 33.35 (021) 66485438 66485457 LWBK914-C03_p47-68. Ratio. • Determine what percentage one number is of another number. • Change a percent to a decimal and a decimal to a percent. • Define the terms ratio and proportion.com 07/11/11 2:13 PM .ketabpezeshki. you should be able to: • Define the term percent. and Proportion LEARNING OBJECTIVES After completing this chapter.CHAPTER 4 Percents. • Solve for x using ratio and proportion in both the fraction and colon format. 69 (021) 66485438 66485457 LWBK914-C04_p69-98.indd 69 www. • Change a percent to a fraction and a fraction to a percent. g. e. 5 5% = 100 • Is a ratio.UNIT 1 Basic Mathematics Review and Refresher 70 Percent A percent: • Refers to a number of parts of something.. 0. 5% 0.com 07/11/11 2:13 PM .45%. For example. These % solutions refer to the grams of the solute or solid.5% www.25% and 0. “parts per hundred. The denominator is 100. per 100 parts of solution. For example. which means 100.” • Is a fraction. The numerator and denominator are separated by a colon. relative to the whole or 100 parts. the numerator is the number before the % symbol. EXAMPLE: 5% 5 100 5 :100 = 0 05 Percents are commonly used when intravenous solutions are prescribed. The numerator is taken to the hundredth part. • Is written with the symbol %. 5% 5:100. For example.05.indd 70 20% 1/2% 20 1/2% 20.ketabpezeshki. The percent symbol can be found with: • • • • A whole number A fraction number A mixed number A decimal number (021) 66485438 66485457 LWBK914-C04_p69-98. • Is a decimal. CHAPTER 4 Percents. and Proportion 71 Fractions and Percents Sometimes it is necessary to change a percent to a fraction or a fraction to a percent to make dosage calculations easier. • This number (20) now becomes the fraction’s new numerator.ketabpezeshki. and change to a mixed number. (021) 66485438 66485457 LWBK914-C04_p69-98. divide the number (new numerator) by 100 (denominator). 20 2 1 = = 100 10 5 • Change to a mixed number if necessary. if necessary. Ratio.indd 71 www. Change a Percent to a Fraction R U L E To change a percent to a fraction: drop the % symbol. • Place this new numerator (20) over 100 (the denominator will always be 100). EXAMPLE: Change 20% to a fraction • Drop the % symbol: 20% now becomes 20. reduce. 20% = 20 = 20 100 • Reduce the fraction to lowest terms.com 07/11/11 2:13 PM . and add the % symbol.ketabpezeshki.com 07/11/11 2:13 PM . reduce.indd 72 www.UNIT 1 Basic Mathematics Review and Refresher 72 EXAMPLE: Change: 40% 40% = 40 = 40 100 40 2 = 100 5 Reduce: ANSWER: EXAMPLE: Change: 2 5 1 % 2 1 1 2 %= 2 100 1 1 1 1 ÷ 100 = × = 2 2 100 200 ANSWER: 1 200 Change a Fraction to a Percent R U L E To change a fraction to a percent: multiply the fraction by 100 (change any mixed number to an improper fraction before multiplying by 100). EXAMPLE: Change: 1 =? 2 1 100 100 50 × = = 2 1 2 1 (021) 66485438 66485457 LWBK914-C04_p69-98. indd 73 www. 2 1 13 = 2 2 50 13 13 ×100 = × 100 1 = 650 2 21 Add % symbol: 650% ANSWER: 650% (021) 66485438 66485457 LWBK914-C04_p69-98.ketabpezeshki.com 07/11/11 2:13 PM . Ratio.CHAPTER 4 Percents. and Proportion 73 50 = 50 1 Add % symbol: 50% ANSWER: 50% EXAMPLE: Change: 3 =? 5 20 3 3 ×100 = × 100 1 = 60 5 51 Add % symbol: 60% ANSWER: 60% EXAMPLE: Change: 6 1 =? 2 1 6 ×100 2 Change 6 6 1 to an improper fraction. 30% 3. 25% 6. Decimals and Percents Sometimes it is necessary to change a percent to a decimal or a decimal to a percent to make dosage calculations easier. 15% 2. 2 3 9.com 07/11/11 2:13 PM .indd 74 www. 1 5 10. 50% 4. 1 3 8. 2 5 12.ketabpezeshki. 3 4 11. (021) 66485438 66485457 LWBK914-C04_p69-98. 1 4 Additional practice problems to enhance learning and facilitate chapter comprehension can be found on http://thePoint.lww. 60% Change the following fractions to percents: 7.74 UNIT 1 Basic Mathematics Review and Refresher PRACTICE PROBLEMS Change the following percents to fractions: 1. 75% 5.com/Boyer8e. ketabpezeshki. Add a zero. ANSWER: 0. EXAMPLE: Change: 68% 68% Drop the % symbol.36 Move the decimal.36. Add a zero. ANSWER: 0. 68% = 68 Decimal replaces % symbol. 36. 0.68 EXAMPLE: Change: 36% Drop the % symbol.com 07/11/11 2:13 PM .1% 14. 36% 36 % = 36 c Decimal replaces % symbol. (021) 66485438 66485457 LWBK914-C04_p69-98.1 14.36 EXAMPLE: Change: 14. 68. .1 Decimal replaces % symbol. and Proportion 75 Change a Percent to a Decimal R U L E To change a percent to a decimal: drop the % symbol (when you drop the % symbol from the whole number.1% Drop the % symbol. 14.0 . Ratio.indd 75 www. 0.68. divide the remaining number by 100 by moving the decimal point two places to the left. a decimal point takes the place of the symbol).CHAPTER 4 Percents. and add zeros if necessary.68 Move the decimal. Add the % symbol. 319 Move the decimal. ANSWER: 319% EXAMPLE: Change: 1.UNIT 1 Basic Mathematics Review and Refresher 76 14. ANSWER: 0. and add the % symbol and zeros if needed. Add the % symbol.1 0.14.5 100 0. ANSWER: 161% EXAMPLE: Change: 0.50 50 Move the decimal. Add the % symbol.ketabpezeshki.indd 76 www. EXAMPLE: Change: 3. ANSWER: 50% (021) 66485438 66485457 LWBK914-C04_p69-98. you need to add a zero.19. Add a zero.com 07/11/11 2:13 PM .61 100 1.1 . Note: To move the decimal point two places to the right.5 0.19 3. 161 Move the decimal.61 1.141 Change a Decimal to a Percent R U L E To change a decimal to a percent: multiply the decimal by 100 by moving the decimal point two places to the right.141 Move the decimal.19 3.61. 33 33% (021) 66485438 66485457 LWBK914-C04_p69-98. EXAMPLE: What percent of 40 is 10? Convert to a fraction: 10 40 Change to a decimal: 10 1 = = 0 25 40 4 Change to a percent: 0.25 25% EXAMPLE: What percent of 60 is 20? Convert to a fraction: 20 60 Change to a decimal: 20 2 1 = = = 0 33 60 6 3 Change to a percent: 0.com 07/11/11 2:13 PM . use the remaining number as the numerator. Ratio. and Proportion 77 Percentage One Number Is of Another Number R U L E To determine what percentage one number is of another number: make a fraction using the number following “what percent of” as the denominator. change the fraction to a decimal.CHAPTER 4 Percents.ketabpezeshki. and then change the decimal to a percent.indd 77 www. 0.60 8. 0. 0. 0. A ratio is used to express a relationship between one unit or part of the whole. 9. 25% 3.78 UNIT 1 Basic Mathematics Review and Refresher PRACTICE PROBLEMS Change the following percents to decimals: 1. 59% 4.85 Determine the percentage one number is of another number.com 07/11/11 2:13 PM . Ratio and Proportion A ratio is the same as a fraction: it indicates division.lww. What percent of 25 is 5? 12.indd 78 www. What percent of 90 is 15? 10. 15% 2.com/Boyer8e. A slash (/) or colon (:) is used to indicate division. 80% Change the following decimals to percents: 5. What percent of 4 is 1/2? 11.45 7.ketabpezeshki.25 6. What percent of 180 is 60? Additional practice problems to enhance learning and facilitate chapter comprehension can be found on http://thePoint.” (021) 66485438 66485457 LWBK914-C04_p69-98. and both are read as “is to” or “per. the ratio to the left of the double colon is equal to the ratio to the right of the double (021) 66485438 66485457 LWBK914-C04_p69-98. a ratio usually refers to the weight of a drug (e. the numerator and the denominator of one fraction have the same relationship as the numerator and denominator of another fraction (they are equivalent). The equals symbol () is read as “as” or “equals.com 07/11/11 2:13 PM .g. Ratio. and the denominator (D) of the fraction is always to the right of the colon or slash. A proportion can be written in the fraction or colon format. Therefore. 50 mg/mL 50 mg of a drug (solute) in 1 mL of a liquid (solution). In the fraction format. and Proportion 79 The numerator (N) of the fraction is always to the left of the colon or slash.. EXAMPLES: 1: 2 1/ 2 = 1 2 2:5 2/5 = 2 5 3: 6 3/6 = 3 1 = 6 2 A Proportion Expressed as a Fraction A proportion is two ratios that are equal. For the ratio of 1 part to a total of 2 parts.indd 79 www.” EXAMPLE: 1 = 3 3 ⎪⎫⎪ ⎬ 9 ⎪⎪⎭ 1 is to 3 as 3 is to 9 A Proportion Expressed in the Colon Format In the colon format.g.ketabpezeshki.. mL). With medications. grams) in a solution (e. you can write 1:2 or 1/2.CHAPTER 4 Percents. UNIT 1 Basic Mathematics Review and Refresher 80 colon. The double colon (::) is read as “as.” You can also use an equals symbol (). The first and fourth terms are called extremes and the second and third terms are called the means. EXTREMES 1:3 :: 3:9 MEANS EXAMPLE: 1:3 :: 3:9} 1 is to 3 as 3 is to 9 1:3 3:9} 1 is to 3 equals 3 is to 9 R U L E To verify that two ratios are equal: multiply the means and then multiply the extremes. The product of the means must always equal the product of the extremes. EXAMPLE: 1:3 :: 3:9 1:3 :: 3:9 199 339 99 ANSWER: 9 R U L E To verify that two fractions are equal: cross-multiply the numerator of each fraction by its opposite denominator and the products will be equal. (021) 66485438 66485457 LWBK914-C04_p69-98.indd 80 www.ketabpezeshki.com 07/11/11 2:13 PM CHAPTER 4 EXAMPLE: Percents, Ratio, and Proportion 81 1 3 : 3 9 1 3 : 3 9 199 339 99 ANSWER: 9 Use of Ratio and Proportion: Solving for x To review, a ratio expresses the relationship of one unit/quantity to another. A proportion expresses the relationship between two ratios that are equal. Sometimes you will have to solve a proportion problem with one unknown quantity, known as x. If the proportion is written in the colon format, multiply the means and then the extremes. Try to keep the unknown x on the left. If the proportion is written in the fraction format, you need to cross-multiply and then divide to solve for x. Solving for x Using a Fraction Format R U L E To solve for x: cross-multiply the numerator of each fraction by its opposite denominator, remembering to keep the x on the left. Divide both sides of the equation by the number before the x. (021) 66485438 66485457 LWBK914-C04_p69-98.indd 81 www.ketabpezeshki.com 07/11/11 2:13 PM 82 UNIT 1 Basic Mathematics Review and Refresher EXAMPLE: Crossmultiply: 1 x = 3 9 x = unknown 3x91 3x 9 Divide both sides of the equation by the number before the x (3). 3 1 Divide: Reduce: 3x 9 = 31 31 x= 3 1 x3 ANSWER: 3 EXAMPLES: 2 x = 5 20 5x 40 x8 1/ 2 x = 10 40 10x 20 x2 36 x = 12 2 12x 72 x6 Note: Because the number before the x is the same in the numerator and denominator of one ratio, these numbers will cross themselves out and equal 1. Therefore, a shortcut is to move the number before the x to the denominator on the opposite side. This quick process is especially important when solving for x in dosage calculation problems. (021) 66485438 66485457 LWBK914-C04_p69-98.indd 82 www.ketabpezeshki.com 07/11/11 2:13 PM CHAPTER 4 Percents, Ratio, and Proportion 83 Solving for x Using a Colon Format R U L E To solve for x: write what you have or know in the colon format (25 : 5), and then write what you desire or the unknown in colon format (50 : x). Therefore, 25 : 5 ⫽ 50 : x. Multiply the extremes (25 ⫻ x), which keeps the x on the left, and then multiply the means (5 ⫻ 50). Then solve for x. A medication example will be presented next in order to illustrate how to apply the concept of solving for x, using ratio and proportion, for drug dosage problems. Applying the Concept of Solving for x Using a Sample Dosage Problem Frequently in dosage calculation problems, one quantity is known (100 mg/mL), and it is necessary to find an unknown quantity because the physician has ordered something different from what is available (75 mg). The unknown quantity (? mL necessary to give 75 mg) is identified as x. The following medication problem will be solved using both the fraction and decimal/colon format. EXAMPLE: Demerol, 75 mg, is prescribed for postoperative pain. The medication is available as 100 mg/mL. To administer the prescribed dose of 75 mg, the nurse would give mL. (021) 66485438 66485457 LWBK914-C04_p69-98.indd 83 www.ketabpezeshki.com 07/11/11 2:13 PM 84 UNIT 1 Basic Mathematics Review and Refresher • For the fraction format, always write down what is available or what you have. You are expressing the ratio relationship of one quantity (mg) to another quantity (mL). Remember, the unit of measurement in the numerator of the fraction must be the same for both fractions. The unit of measurement in the denominator of the fraction also must be the same for both fractions. 100 mg 1 mL • Complete the proportion by writing down what you desire (what the physician had ordered), making sure that the numerators are like units and the denominators are like units in the fraction ratios used. mg mg 100 mg 75 mg :: = :: mL mL 1 mL x mL • Cross-multiply the numerator of each fraction by its opposite denominator and drop the terms used for units of measurement. 100 mg 1 mL :: 75 mg x mL • Complete the proportion: 100 x 75 1 100x 75 • Solve for x by dividing both sides of the equation by the number before x. In this case, the number before (021) 66485438 66485457 LWBK914-C04_p69-98.indd 84 www.ketabpezeshki.com 07/11/11 2:13 PM CHAPTER 4 Percents, Ratio, and Proportion 85 x is 100, so divide both sides of the equation by 100. Convert your answer to a decimal, which is easier to work with than a fraction. Refer to the beginning of this chapter to review the traditional and abbreviated methods for solving for x. For the purpose of brevity, an abbreviated method will be used throughout the remainder of the book. 1 100 x 75 = 100 100 1 x= • Reduce: 75 100 75 3 = mL or 0.75 mL 100 4 ANSWER: 3/4 or 0.75 mL EXAMPLE: Demerol in 75 mg is prescribed for postoperative pain. The medication is available as 100 mg/mL. To administer the prescribed dose of 75 mg, the nurse would have to give mL. • For the decimal/colon format, always write down what is available or what you have. Remember, the unit of measurement to the left of the colon must be the same for both ratios; the unit of measurement to the right of the colon must be the same for both ratios. For this example, you should write: 100 mg : 1 mL (021) 66485438 66485457 LWBK914-C04_p69-98.indd 85 www.ketabpezeshki.com 07/11/11 2:13 PM 86 UNIT 1 Basic Mathematics Review and Refresher • Complete the proportion by writing down what you desire, making sure that both ratios are written in the same format. 100 mg : 1 mL 75 mg : x mL • Multiply the extremes: EXTREMES 100 mg : 1 mL :: 75 mg : x mL (100 mg x mL ) • Multiply the means: 100 mg : 1 mL :: 75 mg : x mL MEANS 75 mg 1 mL) ( • Complete the equation (100 mg x mL 75 mg 1 mL) and drop the units of measurement. 100x 75 • Solve for x. (Remember: divide both sides of the equation by the number before x [100].) Convert your answer to a decimal. 100 x 75 = 100 100 1 100 x 75 = 100 1 100 x= (021) 66485438 66485457 LWBK914-C04_p69-98.indd 86 75 100 www.ketabpezeshki.com 07/11/11 2:13 PM CHAPTER 4 • Reduce: Percents, Ratio, and Proportion 87 75 3 = mL or 0 75 mL 100 4 ANSWER: 3/4 or 0.75 mL Verify Accuracy R U L E To verify the accuracy of an answer obtained by solving for x, determine that the sum products are equal. Verify the accuracy of the answer, x 0.75 mL. • For the fraction format, multiply the numerator of each ratio by its opposite denominator. The sum products will be equal. 100 mg 75 mg :: 3 mL 1 mL 4 25 ⎫⎪ 3 = 75 ⎪⎪⎪ Sum products 41 ⎬ are equal ⎪ 1 75 75 ⎪⎪⎭⎪ 100 × • For the colon format, multiply the extremes and then multiply the means. The product of the means will equal the product of the extremes. EXTREMES 100 mg : 1 mL :: 75 mg : x mL MEANS (021) 66485438 66485457 LWBK914-C04_p69-98.indd 87 www.ketabpezeshki.com 07/11/11 2:13 PM Write the following relationships as proportions. using both the fraction and colon format: 1.ketabpezeshki.UNIT 1 Basic Mathematics Review and Refresher 88 75 ×11 100 × 75 3 100 = 4 1 25 ⎪⎫⎪ ⎪⎪ Sum products ⎬ 3 × = 75 ⎪⎪ are equal ⎪⎪ 41 ⎭ Critical Thinking Check If 75 mg is prescribed and 100 mg/mL is available. A capsule contains 250 mg of a drug. using both the fraction and colon format: 5.4 mg/day provided by 2 tablets.indd 88 www. A liter of IV solution contains 2 ampules of multivitamins. A drug is available in 0.com 07/11/11 2:13 PM .2-mg tablets. The nurse is to give 3 tablets equal to 15 grains. 2. does it seem logical that the quantity to be given would be less than 1.0 mL? _______ Yes or No? PRACTICE PROBLEMS Write the following relationships in ratio format. Pediatric drops contain 50 mg/5 mL. Each tablet contains 5 grains of a drug. 4. There are 325 mg in each tablet. (021) 66485438 66485457 LWBK914-C04_p69-98. 6. 3. A patient is prescribed 0. Use ratio and proportion to solve for x. To give 1. A syrup contains 10 mg/5 mL. 2 x = 7 14 11. An oral liquid is available as 1 gram in each 5 mL.ketabpezeshki. The nurse gave 15 mL or grams. The nurse gave 2 tablets or mg. 5 10 = 25 x 12. Ratio. 4 3 = 12 x 9. A patient is to take 30 mg or 15 mL during a 24-hour period. Set up ratio: proportion and solve for x: (021) 66485438 66485457 LWBK914-C04_p69-98.5 mL. how many milliliters would contain 40 mg? Set up ratio: proportion and solve for x: 13. A drug is available as 25 mg/mL. 8.125 mg. Set up ratio: proportion and solve for x: 15. 6 9 = x 27 10. If 50 mg of a drug is available in 1 mL of solution.CHAPTER 4 Percents. Set up ratio: proportion and solve for x: 14. A tablet contains 0. and Proportion 89 7.indd 89 www. you would give mg.com 07/11/11 2:13 PM . 1. Fraction Decimal 1/6 2. 2/5 6.27 8. 6. 6/7 90 (021) 66485438 66485457 LWBK914-C04_p69-98.ketabpezeshki.62 7.indd 90 www. 21% 5. 0.com 07/11/11 2:13 PM .25 3. 8 3/9% 11. 5 1/4% 9. 1% 12.4% 4. 9/2 10. 0.End of Chapter Review Change the following: Percent 1. A drug is available in 0. 0.075-mg tablets.15 mg daily.72 Write the following ratios in fraction and colon format: 16. A liquid is available for injection as 10 units in each milliliter. 91 18/4 14.5 15. Ratio. A physician ordered 0. A physician ordered 200 mg of a drug per kilogram of body weight. fraction colon 21. A physician ordered 500 mg of a drug.com 07/11/11 2:13 PM . fraction (021) 66485438 66485457 LWBK914-C04_p69-98. The medication was available in 250-mg tablets.CHAPTER 4 Percents. which was available in 100-mg tablets. fraction colon 19. fraction colon 18. A tablet contains 10 mg of a drug. The physician ordered 300 mg of a drug. and Proportion 13.indd 91 colon www. fraction colon 20.ketabpezeshki. 1. fraction colon 17. 0 mL? Yes or No? (021) 66485438 66485457 LWBK914-C04_p69-98. The medication was available as 20 mg/mL. Verify your answer: Critical Thinking Check If one-half the available dosage is prescribed.ketabpezeshki. If x 9 = then x = 12 24 26. The physician prescribed 10 mg of a day. If 3 x = then x = 9 18 Solve for x for the remaining problems and verify your answers using a fraction or colon format: use a critical thinking check to evaluate the logic of your answer. The nurse would give mL. If 1 x = then x = 50 40 24. 23. If 6 2 = then x = 18 x 25. then does it seem logical that the quantity to be given would be less than 1.indd 92 www.com 07/11/11 2:13 PM . A physician ordered 500 mg of a liquid medication that was available as 250 mg/0. using ratios and proportions. fraction colon Solve for x.92 UNIT 1 Basic Mathematics Review and Refresher 22.5 mL. 27. Ratio.ketabpezeshki.com 07/11/11 2:13 PM . nurse would give Verify your answer: Critical Thinking Check If one-half the available dosage (50 mg/5 mL) is prescribed. Verify your answer: (021) 66485438 66485457 LWBK914-C04_p69-98. The nurse would give mL. The physician prescribed 25 mg of a one-dose injectable liquid. The drug was available as 20 mg/ 2 mL.CHAPTER 4 Percents. then does it seem logical that the quantity to be given would be less than 1 mL? Yes or No? 30.indd 93 www. The nurse would give mL. and Proportion 93 28. The syrup was available as 50 mg/5 mL. The physician ordered 1. The medication was available as 3. Verify your answer: Critical Thinking Check If one-half the available dosage is prescribed (3 mg/1 mL). then does it seem logical that the quantity to be given would be less than 3 mL? Yes or No? 29.0 mg/mL.5 mg of an injectable liquid. The physician prescribed 25 mg of a syrup to be given every 3 hours for pain as needed. To give 25 mg. the mL. does it seem logical that the quantity to be given would be greater than 3 mL? Yes or No? 31. The nurse would give tablets. give 37.ketabpezeshki.indd 94 www.4 mg/mL. The physician ordered 35 mg of a liquid that was available as 50 mg/mL. the nurse would give mL. The nurse would give mL. To give 0.com 07/11/11 2:13 PM . The physician prescribed 0. The nurse would give mL. The physician prescribed 40 mg of a solution that was available as 80 mg/15 mL. (021) 66485438 66485457 LWBK914-C04_p69-98.94 UNIT 1 Basic Mathematics Review and Refresher Critical Thinking Check If an additional 25% of the available dosage (20 mg/2 mL) is prescribed. the nurse would give mL. 32. 36. The physician ordered 60 mg of a drug that was available as 20 mg/tablet. The physician prescribed 7. 34. The nurse would mL.6 mg of a medication that was available as 0. The nurse would give mL. To give 40 mg. The physician prescribed 80 mg of a medication that was available as 100 mg/2 mL.6 mg. The physician prescribed 30 mg of an oral solution available as 20 mg/5 mL. 33. 35.5 mg of a medication that was available as 15 mg/mL. 2/3 3/5 3. 17.5 1. 1/10 3/5 4. 0. 1/3 or 1/4 14. 3/30 or 5/30 Solve the following and carry to the nearest hundredths. 1/15 3/150 Choose the fraction with the highest value in each of the following.ketabpezeshki. 1/100 20/30 9.6 0. 13.indd 95 www.6 18. 1/12 1/3 10.End of Unit 1 Review Solve the following problems and reduce each answer to its lowest terms. 1.46 3. 0.8 19. 2/6 4/5 6. 6 0. 1.32 95 (021) 66485438 66485457 LWBK914-C04_p69-98. 1/4 3/4 2. 1/50 20/30 8. 3/8 1/6 7. 3/4 1/3 5. 1/8 or 1/6 15.2 20. 1/3 1/6 11. 1/100 or 1/200 16.com 07/11/11 2:13 PM . 1/10 1/8 12. 0. 2/5 35.45 24. 8.com 07/11/11 2:13 PM . 4 1/2 36. Verify your answers.indd 96 www.96 UNIT 1 Basic Mathematics Review and Refresher 21. 8 : 1 10 : x 40. 1.5 0. 0.5 29.25 10 22. 1/50 Solve for the value of x in each ratio and proportion problem. 8/10 26. 0.5 20 : x 39. 25. 0.5 Change the following fractions to decimals and decimals to fractions. 0.5 4.07 30. 25% 32. 1/3% 33. 25 : 1.ketabpezeshki. 31.25 : 500 x : 1. 4/5 : 25 x : 50 41.5 Change the following percents to fractions and fractions to percents. 37. Reduce all fractions to their lowest terms or carry all decimals to the hundredths or tenths. 0.6% 34. 7.15 100 23. 5/20 27.000 (021) 66485438 66485457 LWBK914-C04_p69-98. 3/9 28. 3 : x 4 : 16 38. com 07/11/11 2:13 PM . 8 : x 48 : 6 52. 1/100 : 5 1/150 : x 50.ketabpezeshki. 1. 20 : x 80 : 8 55. 125 : 250 300 : x 47. 4 : 8 x : 0. 1/5 : 10 1/10 : x 49. and Proportion 97 42. 1/2 : 8 1/8 : x 45.5 54. 15 : x 25 : 150 51. 1/2 : x 1/4 : 0.8 48.5 : 100 43. 3 : x 9 : 1/3 46.CHAPTER 4 Percents.5 : 2 x : 2. x : 20 2. 1/75 : 1/150 2 : x (021) 66485438 66485457 LWBK914-C04_p69-98. Ratio. 10 : 30 60 : x 44.5 53.indd 97 www. (021) 66485438 66485457 LWBK914-C04_p69-98.ketabpezeshki.indd 98 www.com 07/11/11 2:13 PM . Measurement Systems (021) 66485438 66485457 LWBK914-C05_p99-120.indd 99 2 www.com 07/11/11 2:13 PM .ketabpezeshki. ) However. and centimeters). Length is usually used for assessment (inches. this system will be presented here along with the metric and household systems. ounces).ismp.com 07/11/11 2:13 PM . grams.org. nurses need to be familiar with all three systems of measurement and become experts at converting one unit of measure to another within the same system or between two systems. household.indd 100 www. The metric system is the recommended system of choice for dosage calculations because it is the most accurate and consistent. because the apothecary system is still used by physicians (drugs ordered in grains and minims) and two common measurement items (medicine cups and syringes) still include apothecary units. (You can read more about safe medication delivery at http://www. Each measurement system has three basic measures: weight. Equivalent values have been listed to facilitate conversions and dosage calculations. The apothecary system is being phased out because it is an approximate system that is not as exact as the metric system and its use of symbols and Roman numerals is confusing. To effectively deliver medications.T here are three systems of measurement in use today: the metric. millimeters. and apothecary systems. Drugs are commonly prescribed by weight (milligrams. and length. grains) and volume (milliliters. The Joint Commission on the Accreditation of Healthcare Organizations (JCAHO) and the Institute for Safe Medication Practices (ISMP) have both recommended that the apothecary system not be used. is inaccurate because of the variations in household measuring devices.ketabpezeshki. 100 (021) 66485438 66485457 LWBK914-C05_p99-120. which is used most frequently in home settings. volume. In this unit you will be shown how to convert all measurements. The household system. • Make conversions within each system. and Apothecary Systems of Measurement LEARNING OBJECTIVES After completing this chapter.CHAPTER 5 The Metric. household. and apothecary notations.ketabpezeshki. you should be able to: • List the common rules for metric. weight (gram). • Distinguish between the three basic units of measure: length (meter). Household. and volume (liter) for each system.com 07/11/11 2:13 PM .indd 101 www. 101 (021) 66485438 66485457 LWBK914-C05_p99-120. 000 c 0.01 c 100 decreased by 10 ⫽ 100. For example: 1.0 ⫽ 10 c 100 increased by 10 ⫽ 100.0 ⫽ 1. and weight (gram. The metric system of weights and measures is an international decimal system based on multiples of ten. milligram.indd 102 www. ⫽ 10 c (021) 66485438 66485457 LWBK914-C05_p99-120.1 decreased by 10 ⫽ 0. 100. It is also referred to as the International System of Units (SI Units).ketabpezeshki. portions can be increased (multiplied) or decreased (divided) by multiples of 10 (10. The metric system has three basic units of measurement: length (meter). Five common prefixes are used to indicate subunits of measure: micro ⫽ one millionth ⫽ mcg milli ⫽ one thousandth ⫽ m centi ⫽ one hundredth ⫽ c deci ⫽ one tenth ⫽ deci kilo ⫽ one thousand ⫽ kg In the metric system.000). 1.1 ⫽ 0. Conversions are achieved by moving the decimal point to the right for multiplication or to the left for division. volume (liter).com 07/11/11 2:13 PM . microgram and kilogram).102 UNIT 2 Measurement Systems The Metric System The metric system is the most popular system used today for drug prescription and administration because it is the most accurate system.0 increased by 10 ⫽ 1. for which the “L” is capitalized. 0.indd 103 www.com 07/11/11 2:13 PM . Omit unnecessary zeros so the dosage is not misread.CHAPTER 5 The Metric.5 mL not 1/2 mL R U L E Zeros are used in front of the decimal point when not preceded by a whole number to emphasize the decimal.50 mL 1 mL not 1. 0.2 mL 10 kg R U L E Metric abbreviations are written in lowercase letters except for the abbreviation for liter.ketabpezeshki.5 mL not 0. g ⫽ gram mL ⫽ milliliter R U L E Fractional units are expressed as decimals. 0. Household.0 mL (021) 66485438 66485457 LWBK914-C05_p99-120. and Apothecary 103 Common Rules for Metric Notations R U L E Metric abbreviations always follow the unit amount or numbers. 000 ⫽ cm3) • Equal to 1.com 07/11/11 2:13 PM . Millimeters are used for blood pressure measurements.000 mL • Has a mass (1 L of water) equal to one kilogram (1 kg) at 4°C (degrees Celsius) • Abbreviated as L Gram—Weight The gram is: • The basic unit of weight • The most widely used unit of measurement for food products (021) 66485438 66485457 LWBK914-C05_p99-120.37 inches • Abbreviated as m The primary linear measurements used in medicine are centimeters (cm) and millimeters (mm).ketabpezeshki. Centimeters are used for calculating body surface area and measuring such things as the size of body organs. Liter—Volume The liter is: • The basic unit of volume • The total volume of liquid in a cube that measures 10 cm ⫻ 10 cm ⫻ 10 cm (1.indd 104 www. tumors. Square meters are used for body surface area (m2). and wounds.104 UNIT 2 Measurement Systems Meter—Length The meter is: • The basic unit of length • Equal to 39. one-thousandths of the SI base unit of a kilogram • Equal to a volume of 1 mL • Abbreviated as g Refer to Table 5. The Apothecary System Once the first system of measurement for medications. If medications are ordered in (021) 66485438 66485457 LWBK914-C05_p99-120. the apothecary system is not recommended for use today. The abbreviation “gr” is used for grain.1 for common metric measures and equivalents.CHAPTER 5 The Metric.com 07/11/11 2:13 PM .000 grams (g) 1.000 millimeters (mm) • One. and Roman numerals (see Appendix A). Sometimes a medication label indicates grains. the only unit of weight in this system.000 micrograms (mcg) 1.ketabpezeshki. Because the apothecary system may still be used in some instances.000 milligrams (mg) 1. The use of symbols and fractions is confusing and can lead to errors. The symbols for the liquid measures of dram and ounce are no longer used. The apothecary system uses approximate measures. it is presented here.000 milliliters (mL) 100 centimeters (cm) 1 meter (m) ⫽ U 1. Arabic numbers. fractions (for amounts less than 1). and Apothecary 105 Table 5. this is to avoid medication errors.1 Common Metric Measurements and Equivalents 1 gram (g) 1 milligram (mg) 1 kilogram (kg) 1 liter (L) ⫽ ⫽ ⫽ ⫽ 1. Household. and the metric equivalent is in milligrams.indd 105 www. ketabpezeshki. The abbreviation “gtt” is used for drop (see Chapter 10) and “m” for minim. 12 ounces R U L E The apothecary abbreviation/word always goes before the quantity.106 UNIT 2 Measurement Systems drams or ounces.indd 106 www. ss or ss It is helpful to understand the relationship of these terms to the concepts of weight and volume. Common Rules for the Apothecary System R U L E Lowercase Roman numerals are used to express whole numbers. an ounce is equal to 30 mL. A dram is equal to 4 mL. which can be found on some syringes. gr x ⫽ 10 grains drams viii ⫽ 8 drams (021) 66485438 66485457 LWBK914-C05_p99-120. 3 ⫽ iii 6 ⫽ vi R U L E Arabic numbers are used for larger quantities (except for 5. and 20) or when the amount is written out. the words “drams” and “ounces” are written out. One-half can be abbreviated –.com 07/11/11 2:13 PM . The minim is considered equal to the quantity of water in a drop that also weighs 1 grain. The original standard measurement of a grain was an amount equal to the weight of a grain of wheat. 10. (021) 66485438 66485457 LWBK914-C05_p99-120. Because containers in the home differ in design.2 Common Apothecary Units of Weight and Volume Unit Weight or Volume Abbreviation or Term Grain Drop Minim Dram Ounce Pound One drop of water One drop 60 grains 8 drams or 30 mL 12 ounces* gr gtt m dram ounce lb *In this system a pound is slightly less (12 ounces) than the 16 ounces in the household system.CHAPTER 5 The Metric.g. Refer to Table 5.2 for apothecary units of weight and volume. its use is not recommended.indd 107 www. Patients should always be Table 5. gr 1/3). tablespoons. and capacity.. it is impossible to establish a standard unit of measure. and measuring liquid proportions. The abbreviation ss or ss encountered for the fraction 1/2. cups. Household Measurements Household measurements are calculated by using containers easily found in the home. teaspoons. and glasses. Common household measuring devices are those utensils used for cooking.ketabpezeshki.com 07/11/11 2:13 PM . They include medicine droppers. eating. and Apothecary 107 R U L E Fractions are used to express quantities that are less — may be than 1 (e. Household. size. however. 000 mL advised to first use measuring cups or droppers packaged with medications. which calibrates ounces and is available for liquid and dry measures (Figure 5. so every effort needs to be made to be as exact as possible. A medication dropper (sometimes supplied with the prescription) marked in mg and mL or an oral syringe marked in teaspoons is commonly used for children (Figure 5.indd 108 www. It is expected that the household measurement system will increase as health care continues to move into the home and community. (021) 66485438 66485457 LWBK914-C05_p99-120.com 07/11/11 2:13 PM . Some pharmaceutical companies package 1-ounce measuring cups or calibrated medicine droppers with their over-the-counter medications (e..3 Common Household Quantities and Metric Equivalents Unit Volume Abbreviation Drop Teaspoon Tablespoon Ounce Tea cup Measuring cup Pint Quart Gallon — 60 drops 3 tsp 2 tbsp 6 ounces 8 ounces 16 ounces 2 pt 4 qt gtt tsp tbsp oz c C pt qt gal Metric Equivalent — 5 mL 15 mL 30 mL 180 mL 240 mL 500 mL 1. Probably the most common measuring device found in the home is the measuring cup.1).2). The nurse or health care provider will have to teach the patient and family how to measure the amount of medication prescribed. Refer to Table 5.ketabpezeshki.108 UNIT 2 Measurement Systems Table 5.3.g. Children’s Tylenol). NyQuil. CHAPTER 5 The Metric. and Apothecary 109 FIGURE 5.ketabpezeshki.) (021) 66485438 66485457 LWBK914-C05_p99-120. Household. (From Craig. Standard cookbook abbreviations are also used (tsp.]. FIGURE 5. G. The basic unit of this system is the drop (gtt).2 Oral dosage syringe. Clinical Calculations Made Easy [4th ed.1 Standard liquid measuring cup (8–ounce capacity)—a common household container. Philadelphia: Lippincott Williams & Wilkins. A drop is equal to a drop. Common Rule for the Household System R U L E Arabic whole numbers and fractions precede the unit of measure. regardless of the liquid’s viscosity (sticky or gummy consistency).indd 109 www. ¼ cup 8 ounces 3 cups 2 pints The household system of measurement uses Arabic whole numbers and fractions to precede the unit of measure. [2009].com 07/11/11 2:13 PM . oz). tbsp. it is important that the container/dropper be held so that the calibrations are at eye level. Household measurements are approximate in comparison to the exactness of the metric and apothecary systems. the liquid will appear to be uneven or U-shaped. called a meniscus. and household system equivalents. apothecary. when medicine needs to be given in drops. a standard dropper should be used. This curve. is caused by surface tension. determine the container’s capacity prior to preparing the medication. Hospitals use a standard 1-ounce medicine cup (Figure 5. Indicates household. Therefore.indd 110 www.4. These calibrated containers provide metric. (021) 66485438 66485457 LWBK914-C05_p99-120. and metric equivalents. R U L E When measuring a liquid medication in a household container.com 07/11/11 2:13 PM . See Figure 5.ketabpezeshki. apothecary. its shape is influenced by the viscosity of the fluid. When a container/dropper is held at eye level.110 UNIT 2 Measurement Systems FIGURE 5.3). Read the calibration at the bottom of the meniscus when measuring the level of a liquid medication.3 One-ounce medicine cup commonly used in hospitals. When measuring a liquid medication. 4 Liquid medication being read at the bottom of the meniscus. you can always use ratio and proportion. and Apothecary 111 U-shaped curve Bottom of meniscus U-shaped curve Bottom of meniscus FIGURE 5. Converting Within the Same System: Metric System Converting or changing units in the metric system is easily done by moving the decimal point.CHAPTER 5 The Metric. If you choose.com 07/11/11 2:13 PM . (021) 66485438 66485457 LWBK914-C05_p99-120.ketabpezeshki. the container or dropper is held at eye level. Household.indd 111 www. com 07/11/11 2:13 PM . 60. To move from milli to deci.00 ⫽ 60 c (milli) ⫽ (deci) ANSWER: 60 dm (021) 66485438 66485457 LWBK914-C05_p99-120.000 milliliters Move decimal point to the left (smaller unit to larger unit): divide numeral by 10: 1 10 100 1000 1 liter ⫽ 10 deciliters ⫽ 100 centiliters ⫽ 1. The liter is used as an example.000 milliliters R U L E To move from a smaller unit to a larger unit within the same system: Divide the numeral by moving the decimal point to the left the number of places to be moved (move one place for each increment). Move decimal point to the right (larger unit to smaller unit): multiply numeral by 10: 1 10 100 1000 1 liter ⫽ 10 deciliters ⫽ 100 centiliters ⫽ 1. EXAMPLE: Change millimeters (6.ketabpezeshki.UNIT 2 112 Measurement Systems Refer to the following diagram to understand the concept of moving the decimal point when converting dosages.indd 112 www. you need to move the decimal point two places to the left.000) to decimeters. EXAMPLE: Change decimeters (80) to centimeters. and Apothecary 113 R U L E To move from a larger unit to a smaller unit within the same system: Multiply the numeral by moving the decimal point to the right the number of places to be moved (move one place for each increment of 10). To move from deci to centi.CHAPTER 5 The Metric. 0. 3. 20.5 mm ⫽ cm (021) 66485438 66485457 LWBK914-C05_p99-120. 80.0.indd 113 www. 4. ⫽ 800 c (deci) ⫽ (centi) ANSWER: 800 cm PRACTICE PROBLEMS Change the following units of metric length. Household. and weight: 1.ketabpezeshki. 2 mm ⫽ m 5.60 cm ⫽ m 2.16 m ⫽ dm 3.com 07/11/11 2:13 PM .8 mm ⫽ cm 4. you need to move the decimal point one place to the right. volume. 0.40 cg ⫽ mg 15.6 mL ⫽ L 20.000 mg ⫽ g 16.9 L ⫽ mL 14. 18 cm ⫽ mm 7.indd 114 www.17 cL ⫽ mL 13. 0. 3. 10 dm ⫽ m 11.com 07/11/11 2:13 PM . 6. 16 dL ⫽ mL 19. 2 cm ⫽ m 9. 8 g ⫽ cg 18. 41. 1. 6 cm ⫽ mm 10.6 mL ⫽ L 12. 6. 32 dg ⫽ mg (021) 66485438 66485457 LWBK914-C05_p99-120.114 UNIT 2 Measurement Systems 6. 30 dm ⫽ mm 8.ketabpezeshki.8 mg ⫽ dg 17. write down in a fraction or colon format what you know followed by what you desire. If you want to know how many milliliters (mL) there are in 2. and Apothecary 115 Converting Within the Same System: Household and Apothecary Conversions within the same system for the apothecary system and household measures require the memorization of common equivalents.com 07/11/11 2:13 PM . • Write down what you know in a colon or fraction format: 30 mL 1 ounce or 30 mL : 1 ounce • Write down what you desire in a colon or fraction format to complete the proportion. R U L E To change units within the same system: Determine equivalent values. There is a standard rule to use to convert units within the same system.5 ounces. EXAMPLE #1: • Select the equivalent values in the system.indd 115 www. and solve for x.ketabpezeshki.2 and 5.3). The numerators and denominators (021) 66485438 66485457 LWBK914-C05_p99-120.3.CHAPTER 5 The Metric. look up the equivalent value of 30 mL ⫽ 1 ounce (Table 5. which can be found in Tables 5. using ratio and proportion. Converting between systems will be covered in Chapter 6. Household. ketabpezeshki. Remember: The unit used for an answer will be mL. The answer x will be in ounces. If you want to know how many ounces there are in 4 tablespoons.com 07/11/11 2:13 PM .3).5 ounces • Cross-multiply (fraction format) or multiply the extremes and then the means (colon format).5 ounces x mL ⫽ 30 ⫻ 2. 2 tbs 1 oz or 2 tbs : 1 oz • Write down what you desire in a fraction or colon format to complete the proportion. 30 mL : 1 ounce ⫽ x mL : 2.5 x mL ⫽ 75 mL EXAMPLE #2: Select the equivalent values in the system (see Table 5.5 ounces or 30 mL : 1 ounce ⫽ x mL : 2.indd 116 www. • Write down what you know in a fraction or colon format.116 UNIT 2 Measurement Systems must be the same units of measurement. 30 mL x mL :: 1 ounce 2. The answer x will be in ounces. The (021) 66485438 66485457 LWBK914-C05_p99-120. look up the equivalent value of 1 ounce ⫽ 2 tablespoons. CHAPTER 5 The Metric, Household, and Apothecary 117 numerators and denominators must be the same units of measurement. 2 tbs 4 tbs :: 1 oz x oz or 2 tbs : 1 oz ⫽ 4 tbs : x oz • Cross-multiply (fraction format) or multiply the extremes and then the means (colon format). Remember: The unit used for an answer will be in ounces. 2 tbs ⫻ 1 ounce ⫽ 4 tbs ⫻ x ounces 2x ⫽ 4 • Solve for x: 2x 4 = 2 2 21 x 4 = 21 2 x= 42 =2 21 ANSWER: 2 ounces (021) 66485438 66485457 LWBK914-C05_p99-120.indd 117 www.ketabpezeshki.com 07/11/11 2:13 PM End of Chapter Review Change the following units of metric length: 1. 7.43 mm ⫽ m 2. 0.06 cm ⫽ 3. 10 km ⫽ m 4. 62.17 dm ⫽ dm mm Change the following units of metric volume: 5. 1.64 mL ⫽ dL 7. 10 L ⫽ cL 6. 0.47 dL ⫽ L 8. 56.9 cL ⫽ mL Change the following units of metric weight: 9. 35.6 mg ⫽ g 10. 0.3 g ⫽ cg 11. 0.05 g ⫽ mg 12. 93 cg ⫽ mg 13. 100 mcg ⫽ mg 14. 2 mg ⫽ 15. 1.0 mcg ⫽ mg mcg 16. 7 kg ⫽ g Perform the following miscellaneous conversions: 17. 4 mg ⫽ mcg 18. 13 kg ⫽ g 19. 2.5 L ⫽ mL 20. 0.6 mg ⫽ mcg 118 (021) 66485438 66485457 LWBK914-C05_p99-120.indd 118 www.ketabpezeshki.com 07/11/11 2:13 PM CHAPTER 5 The Metric, Household, and Apothecary 119 21. 0.08 g ⫽ mg 22. 0.01 mg ⫽ mcg 23. 60 mg ⫽ g 24. 10.5 mg ⫽ mcg 25. 0.5 mL ⫽ L 26. 100 mg ⫽ dg 27. 3.5 dg ⫽ g 28. 3.4 mg ⫽ g 29. 30 mg ⫽ mcg 30. 13 cg ⫽ g 31. 2 kg ⫽ g 32. 18 L ⫽ mL 33. 450 g ⫽ mg 34. 40 mcg ⫽ mg 35. 8 L ⫽ dL 36. 10 L ⫽ cL 37. 46 g ⫽ dg 38. 0.5 g ⫽ mg L 40. 25 kg ⫽ g 39. 500 mL ⫽ Write the following, using Roman numerals and symbols: 41. 3 grains 42. 5 drams 43. 5 grains 44. 10 minims 45. 20½ minims 46. 5 pints Solve the following: 47. 8 quarts ⫽ gallon(s) 48. 4 drams ⫽ ounce(s) (021) 66485438 66485457 LWBK914-C05_p99-120.indd 119 www.ketabpezeshki.com 07/11/11 2:13 PM 120 UNIT 2 Measurement Systems 49. 2 tablespoons ⫽ ounce(s) 50. gr xxx ⫽ gram(s) 51. 4 pints ⫽ quart(s) 52. 4 ounces ⫽ pint(s) 53. 15 grams ⫽ dram(s) 54. 12 ounces ⫽ teacup(s) 55. 3 glasses ⫽ ounces 56. 6 tablespoons ⫽ ounce(s) 57. 2 teaspoons ⫽ drops 58. 3 tablespoons ⫽ teaspoons 59. 2 cups ⫽ ounces 60. 8 ounces ⫽ pint(s) Additional practice problems to enhance learning and facilitate chapter comprehension can be found at http://thePoint.lww.com/Boyer8e. (021) 66485438 66485457 LWBK914-C05_p99-120.indd 120 www.ketabpezeshki.com 07/11/11 2:13 PM CHAPTER 6 Approximate Equivalents and System Conversions LEARNING OBJECTIVES After completing this chapter, you should be able to: • Identify volume and weight equivalents for the metric and apothecary systems, as well as for household measurements. • Identify linear equivalents for household measures and the metric system. • Convert approximate equivalents between the metric, apothecary and household measurement systems. • Apply three methods of converting between systems: conversion factor, ratio and proportion, and dimensional analysis. 121 (021) 66485438 66485457 LWBK914-C06_p121-132.indd 121 www.ketabpezeshki.com 07/11/11 11:34 AM UNIT 2 122 Measurement Systems I n the preceding chapter, you learned how to change units from one measurement to another within the same system. Frequently, you will have to convert between systems. When converting, you work with approximate equivalents because exact measurements across different systems are not possible. It is essential that you memorize common equivalents and conversions. A common example of such a discrepancy is between the metric and apothecary systems. For example, a medication label will indicate 5 gr, and its equivalent dosage may be written as 300 mg or 325 mg. Both dosages are correct; the equivalent values are approximate. Remember: Most dosage calculations use 60 mg = 1 gr. Because you will have to convert between systems, a table of equivalent values is provided. You must memorize the equivalents found in Table 6.1. Remember that when calculating dosages, division is carried out to two decimal places and decimals are rounded off to ensure accuracy (Appendix B). The metric and English household equivalents for length are rarely used for drug dosage calculations but can be used when applying a paste, cream, or ointment that needs to cover a certain area. However, both are used for linear measurements; for example, to measure wound size, head circumference, abdominal girth, and height. Dosage Calculations: Converting Between Systems Whenever the physician orders a drug in a unit that is in a different system from the drug that is available, (021) 66485438 66485457 LWBK914-C06_p121-132.indd 122 www.ketabpezeshki.com 07/11/11 11:34 AM CHAPTER 6 Approximate Equivalents 123 Table 6.1 Commonly Used Approximate Equivalents: Metric, Apothecary, and Household Systems of Measure Metric Apothecary Household — 1 drop 4 mL 5 mL 15 mL 30 mL 180 mL 240 mL 1 gtt = 1 m (minim) 1 dram — 4 drams 8 drams — — 500 mL 1,000 mL (1 L) 60–65 mg 1 g (1,000 mg) 1 kg (1,000 g) 1 mg = 1,000 mcg 2.5 cm 1 pt 1 qt 1 gr 15 gr — — — — 1 teaspoon (tsp) 1 tablespoon (tbsp) 2 tbsp (1 oz) 1 teacup (6 oz) 1 glass/measuring cup (8 oz) 1 pt (16 oz) = 2 cups 1 qt (32 oz) = 4 cups — — 2.2 lb — 1 inch convert to the available system. You want to work in the system of the drug that you have on hand. R U L E Whenever the desired and available drug doses are in two different systems: Choose the equivalent value and solve for x. Always change the desired quantity to the available quantity. You can use one of three methods to convert between systems: the conversion factor method, ratio and proportion, or dimensional analysis. With each method you must first remember the equivalent value! (021) 66485438 66485457 LWBK914-C06_p121-132.indd 123 www.ketabpezeshki.com 07/11/11 11:34 AM 124 UNIT 2 Measurement Systems The Conversion Factor: Use the equivalent value and either multiply (going from a larger to a smaller unit) or divide (going from a smaller to a larger unit). EXAMPLE: A physician ordered gr 1 1 2 of a medication. You need to give _____ mg. Equivalent value: 1 gr = 60 mg Move from a larger unit (grain) to a smaller unit (milligram). Multiply by the conversion factor (60 mg). gr 1 1 2 60 = 3 60 30 × = 90 mg 1 12 ANSWER: 90 mg Ratio and Proportion: Select the equivalent value and then set up the proportion using either a colon or fraction format. EXAMPLE: #1 Give 1.5 ounces of an elixir that is avail- able in mL. • Change ounces to mL. Choose the equivalent value. 30 mL = 1 ounce • Complete the proportion. Write down what you know. A fraction format is used here. 30 mL x mL = 1 oz 1.5 oz • Solve for x: x = 30 × 1.5 = 45 mL ANSWER: 45 mL (021) 66485438 66485457 LWBK914-C06_p121-132.indd 124 www.ketabpezeshki.com 07/11/11 11:34 AM CHAPTER 6 Approximate Equivalents 125 EXAMPLE: #2 Give gr 1/4 of a drug that is available in mg. Solve for x or the unknown by using a fraction or colon format. Change gr 1/4 to mg (mg are available). 30 kg = lbs (021) 66485438 66485457 LWBK914-C06_p121-132. 12 oz = mL 2. 45 mg = gr 5. 60 mg : 1 gr :: x mg : gr 1/4 x = 60 × 1/4 • Solve for x: 15 60 × 1 = 15. 0. A colon format is used here. 30 mL = tbsp 4. x = 15 mg 41 ANSWER: 15 mg Dimensional Analysis: This is presented in detail in Chapter 8. PRACTICE PROBLEMS Complete the following.indd 125 www. 2 tsp = mL 6.ketabpezeshki. Write down what you know.com 07/11/11 11:34 AM . 60 mg = 1 gr • Complete the proportion. • Select the approximate equivalent value and convert to the system that you have available. 1.3 mL = L 3. • Choose the equivalent value. 3 g = gr 16. 7.ketabpezeshki.2 lb = (021) 66485438 66485457 LWBK914-C06_p121-132. 1 L = 17.indd 126 qt kg mg mL www.com 07/11/11 11:34 AM . 30 mL = oz 12. 3 pt = mL g 10. ss mL 15. 2. 4 tbsp = 13.126 UNIT 2 Measurement Systems Complete the following. 30 gr = mg 8. 300 mcg = 11. 2 qt = L – oz = 18. Solve for x or the unknown by using a fraction or colon format. gr 1/200 = 9. 6 mg = gr 14. 2. The nurse knew that 3 minims were equal to gtt. three times per day.ketabpezeshki. A patient’s abdominal wound measures 10 cm in diameter. 3. 1. The nurse instilled 3 minims of an eye drop into the patient’s right eye. 4. The child’s mother administered tsp each time the medication was given. Solve for x by using a fraction or colon format. 7. A child was prescribed 10 mL of cough syrup four times a day. 6. A patient is restricted to four 8-ounce glasses of water per day or mL per day.End of Chapter Review Complete the following. The nurse knows that this is equivalent to inch(es). Two (2) grams of Metamucil powder is equivalent to gr. The nurse administered aspirin gr v. She knew this was equivalent to mg. 127 (021) 66485438 66485457 LWBK914-C06_p121-132. 5. as needed. A child who weighs 55 lb weighs kg.indd 127 www.com 07/11/11 11:34 AM . 13. he poured the milk of magnesia up to the -ounce calibration line. 9. The medicine is available in oral suspension. 14. Because a medicine cup was available. A 40-lb child was ordered a drug to be given at 10 mg per kg of body weight. 10. The child weighs kg and should receive mg of the drug. three times daily. He is advised not to exceed a daily dose of 3 g or tablets. The medication was labeled in gr per mL.128 UNIT 2 Measurement Systems 8. The nurse gr knew to look for an ampule labeled per mL.4 mg of atropine sulfate to be administered intramuscularly. 12. The physician prescribed 0. A patient who takes 1 tbsp of Kayexalate four times per day would be receiving a daily dose equivalent to ounces. A woman was prescribed 60 mg of a daily vitamin. A patient is to receive 250 mg of a liquid medication.ketabpezeshki. Her cumulative monthly dose (30 days) would be about g. The nurse should give tsp for each dose. 250 mg per 5 mL.com 07/11/11 11:34 AM .indd 128 www. 11. A patient was to take 2 tbsp of milk of magnesia. (021) 66485438 66485457 LWBK914-C06_p121-132. A patient takes a 500-mg tablet three to four times per day. A patient who is prescribed 650 mg would be given tsp. Tylenol liquid is available as 325 mg per 5 mL. equivalent to mg daily. The medication is available in 0.CHAPTER 6 Approximate Equivalents 129 15. (021) 66485438 66485457 LWBK914-C06_p121-132. The nurse would give tablets each dose. 18. three times a day.lww.indd 129 www. Each dose would be mg for a daily total dosage of g. The tablet is available in 200-mg quantities. three times daily. The nurse restricts the water needed for swallowing the medications so the patient can have fluids with his meals. Additional practice problems to enhance learning and facilitate chapter comprehension can be found at http://thePoint. A child is prescribed a 250-mg tablet every 6 hours. A renal patient whose daily fluid intake is restricted to 1.200 mL per day is prescribed eight oral medications. The patient is allowed 5 ounces of water. The patient would receive g per day. The nurse would give tablespoon(s). 19. 17.3 mg of a drug. four times a day. the patient has mL with his drugs. 16. with his medications.com/Boyer8e. twice daily.ketabpezeshki. A patient is to receive a 200-mg tablet every 12 hours.15-mg tablets. A patient is to receive 30 mg of a drug available as 10 mg per teaspoon. The nurse gives two tablets. A physician prescribes 0. Therefore.com 07/11/11 11:34 AM . 20. 1. 3.080 g = 2. 15 grains = 10. 1. 0.2 L = mg mL 3. 1/2 qt = 11. 3 pt = 12. 155 lb = 8.ketabpezeshki.End of Unit 2 Review Convert each item to its equivalent value. 5 mg = g 7.500 mcg = mg 4.indd 130 www.125 mg = mcg 5.com 07/11/11 11:34 AM . 0. 20 kg = g 6. 8 drams = kg gtt gram(s) ounces quart(s) ounce(s) 130 (021) 66485438 66485457 LWBK914-C06_p121-132. 30 minims = 9. 15 mg = gr 30. 30 g = ounce(s) 19. 1 tbsp = 14.com 07/11/11 11:34 AM . 1 teacup = 16. 2 tbsp = ounces ounce(s) –= 17. gr 1 = mg 21.5 g = 28. 6 tsp = Approximate Equivalents tsp ounce(s) 15.3 mg = gr 25. 8. 0. 1. gr 1/150 = mg 24.8 oz = mL 26. 950 mg = mg g 29. 6 mg = mcg (021) 66485438 66485457 LWBK914-C06_p121-132. 20 kg = lb 23. 20 mL = tsp 27.ketabpezeshki. gr ss mg 18.indd 131 131 www. 3 tsp = mL 22.CHAPTER 6 13. 1 oz = mL 20. com 07/11/11 11:34 AM .indd 132 www.(021) 66485438 66485457 LWBK914-C06_p121-132.ketabpezeshki. Dosage Calculations (021) 66485438 66485457 LWBK914-C07_p133-146.ketabpezeshki.indd 133 3 www.com 07/11/11 1:20 PM . mL)—for example. Critical care intravenous solutions are prescribed in smaller quantities and administered via an electronic infusion pump. 50 mg per mL. or dimensional analysis. Intravenous solutions are available in various quantities (e. heparin. Some are available as single-dose preparations. the Institute for Safe Medication Practices (ISMP) has recommended that the slash line (/) not be used when writing medication orders. Oral medications contain a solid concentration of drug.000 mL). the Formula Method. To minimize the possibility or obtaining or preparing the wrong dosage.g.. and others are available in multiple doses.ketabpezeshki.A ccurate dosage calculations are an essential component of the nursing role in the safe administration of medications. Liquid medications contain a specific amount of drug. Remember: You should never prepare or administer any medication that is not clearly labeled. and 1. grams per 1 mL of solution).com 07/11/11 1:20 PM .g. 25 mg per 5 mL. Demerol. Although not universally 134 (021) 66485438 66485457 LWBK914-C07_p133-146. penicillin). and others need to be reconstituted from a powder. ampules. as outlined in Chapter 7. or Vistaril. This unit will present common dosage calculations for oral and parenteral routes for adults and children. Dosages usually range from 1 mL to 3 mL. Each label must contain specific information. dissolved in solution (e. usually gram weight. Medication orders refer to drug dosages. and premeasured syringes. so calculations will be necessary if a dosage prescribed is different (with regard to system and/or unit of measurement) from the available dosage. some are found in solutions as milliequivalents (mEq. 250 mL.. 500 mL. Medications are prescribed by their generic (official) name or trade (brand) name and are usually packaged in an average unit dose. insulin.. per quantity of one.g. Some drugs are measured in units (e. Oral and parenteral dosage calculations can be completed using ratio and proportion. Parenteral medications are packaged in vials. All medications come packaged and are clearly labeled. Examples of these dosage calculations are given in Chapter 11. which will be introduced in Chapter 8.indd 134 www. See Appendix K for nursing concerns for geriatric drug administration. some institutions are starting to enforce this recommendation. Appendix J suggests nursing considerations for critical care drug administration. or body surface area. Refer to Appendix I for nursing concerns for pediatric drug administration. due to the necessity of brevity for this handbook. and used. You can read further about this recommendation at http://www.com 07/11/11 1:20 PM . If you are going to give pediatric drugs. pediatric dosages are based on age.ketabpezeshki. Infants and children cannot receive the same dose of medication as adults because a child’s physiologic immaturity influences how a drug is absorbed. The older adult also responds differently in the metabolism of medications. However. you will notice that the slash is not used in this text or in word problems. Therefore. you must become familiar with the rules for calculating pediatric dosages. body weight.indd 135 www.org. which are given in Chapter 14. excreted. distributed.ismp. the slash line is used within calculations. 135 (021) 66485438 66485457 LWBK914-C07_p133-146. Therefore.implemented. indd 136 www.CHAPTER 7 Medication Labels LEARNING OBJECTIVES After completing this chapter. • Recognize when drug dosage calculations. and quantity on a medication label. when the prescribed dose is different than the available dose.com 07/11/11 1:20 PM . you should be able to: • Identify a drug’s generic and trade name on a medication label. are necessary—for example. • Interpret drug administration requirements and precautions on a medication label.ketabpezeshki. • Interpret drug manufacturing information on a medication label. • Interpret drug reconstitution or mixing directions on a medication label. • Identify drug dosage strength. 136 (021) 66485438 66485457 LWBK914-C07_p133-146. form. including equivalent conversions. . • Generic or official name: This is the name given by the company that first manufactures the drug. under the brand name. • Drug name: Medications are prescribed by their trade or generic name.ketabpezeshki. labeling is changing to show the generic name in uppercase letters and bolded (e. Several drug labels will be depicted as examples. Reading and Interpreting a Drug Label Some labels are easy to read because they contain a limited amount of information—for example. MEPERIDINE). with the dosage of each drug clearly visible. This is the most common type of label that you will see in a hospital setting. However. It appears in smaller letters. because many physicians are now ordering by generic name. sometimes in parentheses. and sample drug problems will be presented.indd 137 www. labels for unit-dose preparation where each tablet or capsule is separately packaged.g.CHAPTER 7 Medication Labels 137 T o prepare the correct medication that is prescribed. but it may have many different trade names. you must be able to accurately read a drug label and be familiar with major key points presented in this chapter. A drug has only one chemical name. You should be able to recognize the following information on a medication label. As a cost-control (021) 66485438 66485457 LWBK914-C07_p133-146. ATROPINE. Other labels indicate multiple tablets or capsules. Drug labels contain essential and comprehensive information for the safe administration of medications.com 07/11/11 1:20 PM . each using its own trade name. mcg).5 mg per day to 25 mg per day means that a patient may receive 1 to 2 tablets daily. in a solid form within a liquid (e. 1:1.. injectables. oral suspensions. large. The usual dose of 12.1). mEq.g. or capital letters on the label. 1% in 0.. 50 mg per mL).indd 138 www.g. 40-mg capsules. unless contraindicated by the physician. Demerol.g. Sometimes the dosage is expressed in two systems (e.com 07/11/11 1:20 PM . mg per mL). For example.000 units per mL). (021) 66485438 66485457 LWBK914-C07_p133-146. • Trade. • Drug dosage and strength: This is the amount of drug available by weight per unit of measure (e.138 UNIT 3 Dosage Calculations effort. brand. in solutions (e.5 mg of the solid drug carvedilol. tablets. It is printed in bold. capsules...g. g. The drug may be manufactured and marketed by several companies.5 oz).. Nitrostat 0. The ® identifies manufacturer ownership. or in other preparations such as ointments or patches (e. Dosage strength is indicated in a solid form (e.. Nexium. 1.000).ketabpezeshki.4 mg [1/150 gr]). If a trade name is followed by ™ it means that the trade name is trademarked and cannot be used by another manufacturer. • Drug form: This refers to the form in which the drug is prepared by the manufacturer—for example. for Coreg (see Figure 7. or proprietary name: This is the commercial or marketing name that the pharmaceutical company gives a drug. mg. some insurance companies are now requiring that pharmacists offer a generic brand first.. in units (e. Examine the drug label for multiple doses. each of the 100 tablets contains 12.g.g.g. g.g. ointments. SC. lidocaine 2%). Philadelphia.2. 50 mL). and so on. 5 mL.g.. and patches. milliequivalents (number of grams in 1 mL of a solution). 10 mL) or the total amount of liquid available after reconstitution (e. IV. topical.) suppositories.ketabpezeshki. controlled release (CR). rectal. 100 units per mL (insulin dosages).CHAPTER 7 Medication Labels 139 FIGURE 7. and double strength (DS). and powdered (021) 66485438 66485457 LWBK914-C07_p133-146. See Figure 7.or multiple-use vials. Parenteral preparation labels indicate dosages in a variety of ways: percentage and ratio strengths. The label will also indicate single.1 Coreg. such as oral.. which shows the drug label for Augmentin. otic. When the powder is reconstituted with 47 mL of water. sublingual. PA.indd 139 www. The drug label may also indicate specific characteristics of the drug’s form— for example. long acting (LA). each 5 mL of liquid contains 200 mg of the drug. (Courtesy of GlaxoSmithKline. 100 tablets. or doses expressed as a ratio or percent (e.. • Drug route of administration: The route may be indicated on the label. • Drug quantity: This is the total amount of the drug in the container (e.com 07/11/11 1:20 PM . sustained release (SR). Some drugs are prepared in several forms. IM. 30 capsules. See Figure 7. heparin (store at controlled room temperature [59°F to 86°F]). • Drug reconstitution or mixing: As shown in Figures 7. Always follow these directions to ensure the accuracy of drug preparation.1. promethazine HCl (protect from light and keep covered in the carton until time of use). For example: Septra tablets (store at 59°F to 77°F in a dry place). control numbers. Expiration dates indicate the last date that the drug should be used.140 UNIT 3 Dosage Calculations forms that have reconstitution directions.3. a National Drug Code (NDC) number that is different for every drug. drug labels must contain the following information: manufacturer name.com 07/11/11 1:20 PM . expiration or volume date. which presents the drug label for Ancef. a bar code (used for a drug distribution system). Each vial contains approximately 330 mg per mL (IM use) after the addition of 2 mL of sterile water. Never give a drug beyond its expiration date! (021) 66485438 66485457 LWBK914-C07_p133-146. These are identified in Figure 7. • Drug manufacturing information: By federal law. • Drug precautions: Drug labels also contain precautions about storage and protection from light. and a code identifying one of two official national lists of approved drugs: USP (United States Pharmacopeia) and NF (National Formulary).3. and Coreg (protect from moisture).2 and 7.ketabpezeshki.indd 140 www. the directions for mixing and reconstitution are clear on the drug labels. com 07/11/11 1:20 PM . (Courtesy of GlaxoSmithKline.2 Augmentin.ketabpezeshki. Reconstitute: reconstitution 5.indd 141 www. referring to the respective medication labels. Precautions: 4. Dosage strength: 3. Reconstituted dosage: 6.) 1. PA.CHAPTER 7 Medication Labels 141 PRACTICE PROBLEMS Fill in the blanks for the following questions. Generic name: 2. Drug volume after reconstitution: (021) 66485438 66485457 LWBK914-C07_p133-146. FIGURE 7. Philadelphia. Philadelphia. (Courtesy of GlaxoSmithKline. Reconstitute: 4.3 Ancef.142 UNIT 3 Dosage Calculations FIGURE 7.com 07/11/11 1:20 PM .indd 142 www.) 1. Approximate dose per mL after reconstituting: 5. Identify two routes of administration: and 3. Precautions: (021) 66485438 66485457 LWBK914-C07_p133-146. PA.ketabpezeshki. Usual adult dose: 6. Proprietary name: 2. ketabpezeshki.com 07/11/11 1:20 PM . Drug quantity: 5. NDC number: 3. Manufacturer: (021) 66485438 66485457 LWBK914-C07_p133-146.) 1. Precautions: 7. Dosage strength: 4.CHAPTER 7 Medication Labels 143 FIGURE 7. Trade name: 8. Generic name: 2. PA.indd 143 www. Philadelphia.4 Requip. Drug form: 6. (Courtesy of GlaxoSmithKline. com 07/11/11 1:20 PM .indd 144 www. 144 (021) 66485438 66485457 LWBK914-C07_p133-146.5 Tagamet.End of Chapter Review Answer each question by referring to the specific drug labels presented in the accompanying figures. twice daily. Philadelphia.ketabpezeshki.) 1. FIGURE 7. The nurse would administer tablet(s) for each dose. The patient would receive mg of Tagamet in 24 hr. PA. (Courtesy of GlaxoSmithKline. A physician prescribed 600 mg of Tagamet. (Courtesy of GlaxoSmithKline. The nurse would administer mL for each dose.7 Augmentin.ketabpezeshki. The child would receive mg and mL in 24 hr.com 07/11/11 1:20 PM . The medication is given every 6 hr.) 2. Philadelphia. (021) 66485438 66485457 LWBK914-C07_p133-146. Philadelphia. FIGURE 7.indd 145 www. A patient is to receive 2 g of amoxicillin (Amoxil) every 24 hr for 10 days.6 Amoxil. The patient would receive mg or tablet(s) for each dose. PA.) 3. A physician prescribed 100 mg of Augmentin every 8 hr for a 3-year-old. PA.CHAPTER 7 Medication Labels 145 FIGURE 7. (Courtesy of GlaxoSmithKline. 146 UNIT 3 Dosage Calculations FIGURE 7.indd 146 www.) 4.ketabpezeshki.8 Paxil. (Courtesy of GlaxoSmithKline. Philadelphia. PA. A physician prescribed 40 mg of Paxil twice a day. The patient would receive tablet(s) per dose and mg per day.com 07/11/11 1:20 PM . (021) 66485438 66485457 LWBK914-C07_p133-146. • Apply ratio and proportion to solve oral drug dosage problems.CHAPTER 8 Oral Dosage Calculations LEARNING OBJECTIVES After completing this chapter. you should be able to: • Describe the various types of oral medications. • Apply dimensional analysis to solve oral drug dosage problems. • Understand the rationales for critical thinking checks. 147 (021) 66485438 66485457 LWBK914-C08_p147-171.ketabpezeshki.com 07/11/11 11:36 AM . • Solve dosage calculation problems for medications in similar and different measurement systems (use equivalent values when necessary). • Apply the Formula Method to solve oral drug dosage problems.indd 147 www. ketabpezeshki. using sample problems. nurse practitioner) differs from the available quantity. Drugs are prescribed by mouth (PO). and caplets come in the dosage prescribed. This chapter will present three methods to solve dosage calculation problems: proportions (using either two ratios [colon format] or two fractions [fraction format]). Each method of problem solving will be demonstrated. emulsions. suspensions.UNIT 3 148 Dosage Calculations O ral medications come in a variety of forms: caplets (a capsule coated for ease of swallowing). micrograms). tablets. and dimensional analysis. liquid calculations usually involve milliliters. or through a percutaneous endoscopic gastrostomy tube (PEG). and syrups).com 07/11/11 11:36 AM . An end-of-chapter review is provided to (021) 66485438 66485457 LWBK914-C08_p147-171. When the dosage prescribed by the health care provider (physician. Each method requires understanding measurement systems and system equivalencies. Most tablets. enterally. milligrams. through a gastrostomy tube. Dosage calculations for solid drugs usually involve tablets (grains. solutions. Sublingual tablets are placed under the tongue and absorbed through the circulation. dosage calculation is required. controlled-release (CR). the Formula Method. breaking a scored tablet in half. and pills. capsules (a powdered or liquid form of a drug in a gelatin cover). capsules. grams. via a nasogastric (NG) tube. or the prescription requires giving more than one pill. or extended release (XL) tablets should be taken whole. or crushing and/or mixing a dose when swallowing is difficult. Each section is followed by practice problems. Entericcoated tablets (a coating that promotes intestinal rather than gastric absorption) and sustained-release (SR).indd 148 www. liquids (elixirs. When calculating oral dosages.1 for an example of an oral drug medication label. or dimensional analysis.indd 149 www. Philadelphia.1 Tagamet... mg).) reinforce the steps of calculation. PA. To do this you need to use an equivalent value. For a quick review here. (Courtesy of GlaxoSmithKline. you need to (021) 66485438 66485457 LWBK914-C08_p147-171. See Figure 8. mcg. dosage calculations are easy. the Formula Method. When the prescribed or desired dosage is different from what is available or what “you have” (different systems or different units) you must convert to the same system (usually metric) and the same units (the smaller the better) before calculating dosages.g.ketabpezeshki.CHAPTER 8 Oral Dosage Calculations 149 FIGURE 8. Calculating Oral Dosages When medications are prescribed and available in the same system (e. you can use ratio and proportion. Ratio and Proportion Ratio and proportion is explained in detail in Chapter 4.com 07/11/11 11:36 AM . grains. metric) and the same unit of size (e.g. Follow this with the unknown ratio (10 mg : x mL). mL) is the quantity (Q) that is multiplied by the terms in the fraction labeled (D/H). first write down the known ratio (25 mg : 1 mL). The symbol is used throughout this book to indicate “desired amount. When calculating dosage problems.” R U L E To apply the Formula Method: the prescribed amount of drug becomes the desired (D) amount and the numerator of the fraction. The unknown (x) is what you need to calculate to give the medication. first write down mg the known fraction 25 . followed by the unknown 1 mL 10 mg fraction x mL . Sometimes it will be necessary to convert between systems (use equivalents) before calculating the dosage.150 UNIT 3 Dosage Calculations remember that you can work with the two ratios. ( ) ( ) The Formula Method The Formula Method is a quick way to solve dosage calculations. the x will be the unknown amount—the amount of medication that you want to give.indd 150 www. Two examples will be provided after the Rule. the drug that is available—the amount that you have (H)—becomes the denominator of the fraction.ketabpezeshki. in either a colon or fraction format. Always use critical thinking checks to make sure that your answer is logical. and the drug form (tablet. Cross-multiply and then divide both sides of the equation by the number in front of x. If you are using a colon format. If you are using a fraction format. (021) 66485438 66485457 LWBK914-C08_p147-171.com 07/11/11 11:36 AM . expressed as a proportion. Then multiply the means by the extremes to solve for x. CHAPTER 8 Oral Dosage Calculations 151 The Formula Method: The Basic Equation: D ((desired amount) × Q ((quantity i ) H ((have on hand) = x (amount to give gi ) ⎧⎪⎪ D ⎫⎪ ⎨ × Q = x ⎪⎬ ⎪⎪⎩ H ⎪⎪⎭ D = desired (prescribed) amount in the given units of measurement H = what you have (available). drug form (tablet. then 501 multiplication) x=2×1=2 ANSWER: 2 tablets EXAMPLE: #2 Th he physician prescribed gr 1/2 of a medication that is available as 15 mg per tablet. you need to first convert to the same (021) 66485438 66485457 LWBK914-C08_p147-171. the dosage strength Q = quantity. Note: Because you have two systems.indd 151 www. D ((desired) ×Q tablets H ((have) 100 mg ×1 = x 50 mg 100 2 ×1 = x (use cancellation.ketabpezeshki. the unknown dosage EXAMPLE: #1 Th he physician prescribed 100 mg of a medication that is available as 50-mg tablets.com 07/11/11 11:36 AM . mL) x = amount to give. for this problem. Always convert to the system that is available! Therefore. Its popularity in nursing is increasing.152 UNIT 3 Dosage Calculations system. Placement of the units of the fractions is important for multiplication and cancellations to be accurate. thus minimizing errors and eliminating the need to memorize a formula. Dimensional analysis is used frequently in the sciences to solve chemistry equations. Dimensional analysis uses one equation (fraction method).com 07/11/11 11:36 AM . The unit in the denominator of the second fraction must be the same as the unit in the numerator of the first fraction. conversion factors (equivalents) will be needed if the units are not in the same system. Use the equivalent 60 mg = 1 gr. x = 2 × 1 = 2 ANSWER: 2 tablets Dimensional Analysis Dimensional analysis (DA) is a problem-solving method also known as the unit-factor method or the factor-label method. then mul15 1 tiplication).indd 152 www. (021) 66485438 66485457 LWBK914-C08_p147-171. convert grain to mg. Frequently. 60 mg : 1 gr = x mg : gr 1/2 x = 60 × 1/2 x = 30 mg D ((desired) ×Q tablets H ((have) 30 mg ×1= x 15 mg 2 30 × 1 = x (use cancellation.ketabpezeshki. (021) 66485438 66485457 LWBK914-C08_p147-171.indd 153 www.ketabpezeshki. what you have. multiply the numerators. • Wanted quantity: the answer (x). and one starts with the wanted quantity. • Factors: dosages in fraction format. One problem will be used to demonstrate each of the four approaches. what you desire. • Available dose: the available amount of the drug. • Computation: the calculation process.CHAPTER 8 Oral Dosage Calculations 153 The Basic Terms for Dimensional Analysis: • Desired dose: the dose to be given. that is. and then divide the product of the numerators by the product of the denominators. mL. Cancel first. There is more than one way to set up a dimensional analysis equation. EXAMPLE: Give 120 mg of a drug that is available as gr i per tablet. • Units: the measure of the drug form (tablet. mg. oz. • Unit placement or path and cancellation: placement of the units of the fractions in the numerator and the denominator positions so cancellation can occur. Three of the following examples start with the given quantity. mL). There are four ways to set up the equation. • Conversion factors: the equivalents used to convert between systems. Use a conversion factor. multiply the denominators. You can begin with the given quantity (desired dose) or the wanted quantity (x). Also known as the given quantity.com 07/11/11 11:36 AM . the equation is designed for multiplication and cancellation. No matter which fraction placement you use. indd 154 www.154 UNIT 3 Dosage Calculations Start with the Given Quantity: Use a Vertical Line to Separate the Fractions 120 mg 1 tabl a et gr i gr i 60 mg 120 mg 1 tabl a et gr i gr i 60 mgg 2 = 120 × 1 ( tabl ablet) × 1 120 2 = = = 2 tabl a ets 60 60 1 1 Start with the Given Quantity: Use an x to Separate the Fractions 120 mg 1 tabl a et gr i × gr i 60 mg 120 mg 1 tabl a et gr i × × gr i 60 mg 120 ×11 ( tabl tablett) 1 = 60 × 2 = 120 2 = = 2 tabl a ets 60 1 1 Start with the Given Quantity: Use an = Sign to Separate the Fractions 120 mg 1 tabl a et gr i = = gr i 60 mg 120 mg 1 tabl a et gr i = = gr i 60 mg 2 120 ×11 ( tabl tablett) 1 120 = 60 60 1 2 = = 2 tabl a ets 1 = (021) 66485438 66485457 LWBK914-C08_p147-171.com 07/11/11 11:36 AM .ketabpezeshki. ketabpezeshki. dimensional analysis equations will begin with the given quantity. This given quantity will be the numerator of the first fraction. The remaining (021) 66485438 66485457 LWBK914-C08_p147-171.CHAPTER 8 Oral Dosage Calculations 155 Start with the Wanted Quantity: Use an = Sign After the x x tabl a ets(s) = 1 tabl a et 120 mg × × gr i gr i 60 mg 2 120 ×1 (ta tablet)×1 120 2 = = 60 60 1 1 = 2 tabl a ets = Note: For this book.indd 155 www. Use an x to separate the fractions. EXAMPLE: G 250 mg of a drug. • Write down what you desire (250 mg). R U L E To apply the dimensional analysis formula: Follow the steps in the following example. The drug is availGive able as 500 mg per tablet. 250 mg × 1 tabl a et = 500 mg • Cancel the opposite and matching units of measure in the denominators and numerators. Placement of the units must be set up to allow for cancellation. 250 mg • Write down what you have available (500 mg per tablet) as the second fraction.com 07/11/11 11:36 AM . The denominator of the second fraction must be in the same units as the numerator of the first fraction. ketabpezeshki. The equivalent value is 1 g = 1.156 UNIT 3 Dosage Calculations measure (tablet) is what is desired. • Write down what you desire (0. Cancel the opposite and matching units of measure in the denominators and numerators. 250 mg 1 tabl a et =x 500 mg 250 mg 1 tabl a et 250 ×1 ( bl ) = = 500 mg 500 = × 250 1 500 2 = 1 = 2 1 2 tabl a et ANSWER: 1 2 tablet R U L E To apply the dimensional analysis formula using a conversion factor (equivalent): Follow the steps in the following example.5 g of a drug. The (021) 66485438 66485457 LWBK914-C08_p147-171. Complete the mathematical calculations. 0. 0. EXAMPLE: Givve 0.5 g × 1 tabl a et 250 mg • A conversion factor is needed because the units are not the same. This given quantity will be the numerator of the first fraction.5 g • Write down what you have available (250 mg per tablet) as the second fraction.com 07/11/11 11:36 AM .indd 156 www.000 mg. The medication is available as 250 mg per tablet.5 g). the colon format will be used when working with ratio and proportion.ketabpezeshki.250 mg : x 0. EXAMPLE #1: : 0.250 mg Have: 0. 000 mg = 250 mg 1g 2 0.CHAPTER 8 Oral Dosage Calculations 157 remaining measure (tablet) is what is desired.55 g 1 tablet 1. 000 500 = = 250 2500 1 25 2 = = 2 tabl a ets 1 ANSWER: 2 tablets × Dosage Calculations for Medications in the Same System and the Same Unit of Measurement R U L E When the desired and available drug doses are different but in the same system and same unit of measurement: Use one of the following three methods to calculate dosages. 0.indd 157 www.5 1 ( tabl a et) 1. You can also use the fraction format if you wish.125 mg : 1 tablet = 0. Complete the mathematical calculations.125-mg tablet Give: _______ tablet(s) This sample problem will be solved using all three methods.250 (021) 66485438 66485457 LWBK914-C08_p147-171.125x = 0. Ratio and Proportion 0.com 07/11/11 11:36 AM . For this chapter. ketabpezeshki.125 m mgg 0.125 1 1 ANSWER: 2 tablets Dimensional Analysis 0.250 0.250 mgg 1 tabl a et = × 0.125 × 2 = 250 2 = = 2 tabl a ets t 125 1 1 ANSWER: 2 tablets EXAMPLE #2: : gr 1/2 p.250 2 ×x = = = 2 tabl a ets 0.com 07/11/11 11:36 AM .n.r. Have: gr 1/4 per tablet Give: ______ tablet(s) (021) 66485438 66485457 LWBK914-C08_p147-171.250 2 = = 2 tabl a ets 0.indd 158 www.125 0.158 UNIT 3 Dosage Calculations 2 x= 0.250 5 ×1 ( tabl a et) = 0.125 1 1 ANSWER: 2 tablets The Formula Method D ×Q = x H 2 0.250 mg 1 tabl a et 0.125 mg 0. com 07/11/11 11:36 AM .CHAPTER 8 Oral Dosage Calculations 159 Ratio and Proportion gr 1/4 : 1 tablet = gr 1/2 : x tablets 1/4x = 1/2 1 x= 1 2 2 = 4 1 4 × = 2 tablets 21 1 ANSWER: 2 tablets The Formula Method D ×Q = x H gr 1 2 1 42 2 = × = = 2 tabl a ets gr 1 4 21 1 1 ANSWER: 2 tablets Dimensional Analysis gr = = 1 2 × ggr 1 1 1 2 4 1 tabl a et gr 1 4 2 × 1 tabl a et = gr 1 4 1 a et e) 2 ×1 ( tabl 1 4 2 = 1 4 2 × = = 2 tabl a ets 21 1 1 ANSWER: 2 tablets (021) 66485438 66485457 LWBK914-C08_p147-171.indd 159 www.ketabpezeshki. indd 160 www.com 07/11/11 11:36 AM .160 UNIT 3 EXAMPLE #3: Dosage Calculations : 100 mg Have: 20 mg per 5 mL Give: ______ mL Ratio and Proportion 20 mg : 5 mL = 100 mg: x 20x 0 = 500 25 x= 500 50 = = 25 mL 20 21 ANSWER: 25 mL The Formula Method D ×Q = x H 25 100 mg 500 50 ×5 = = = 25 mL 20 mg 20 21 ANSWER: 25 mL Dimensional Analysis 100 mg 5 mL 20 mg 100 mgg 5 mL 100 5 (mL) = × = 20 mg 20 × 5 50 = 25 500 50 = = 25 mL 20 2 21 ANSWER: 25 mL (021) 66485438 66485457 LWBK914-C08_p147-171.ketabpezeshki. 000 8 x= 4. and use one of the three methods to calculate dosages.ketabpezeshki. change to the smaller unit.0 g) three places to the right: 4. EXAMPLE #1: : 4 g daily Have: 500 mg per tablet Give: ______ tablet(s) CONVERT TO LIKE UNITS: To convert 4 g to mg.000.000 mg : x 500x 0 = 4.com 07/11/11 11:36 AM .CHAPTER 8 Oral Dosage Calculations 161 Dosage Calculations for Medications in the Same System but with Different Units of Measurement R U L E When the desired and available drug doses are in the same system but different units of measurement: Convert to like units.000 mg Ratio and Proportion 500 mg : 1 tablet = 4. Then 4 g = 4. move the decimal pooint (4. 000 40 = = 8 tabl a ets 500 51 ANSWER: 8 tablets (021) 66485438 66485457 LWBK914-C08_p147-171.indd 161 www. com 07/11/11 11:36 AM . move the decimal pooint (1. 000 mg = 500 mg 1g 4 g 1 ( t ablet) 1.2 g = 1. 000 40 = = 8 tablets 5 0000 5 5 ANSWER: 8 tablets EXAMPLE #2: : 1. 000 mg × 1= x 500 mg 8 4.indd 162 www. 000 mg = × = 500 mg 1g = × 4 ×1 ( bl ) ×1.200. 000 = 500 ×1 40 4.200 mg (021) 66485438 66485457 LWBK914-C08_p147-171.2 g in two equally divided doses Have: 600 mg per tablet Give: _____ tablet(s) CONVERT TO LIKE UNITS: Too convert 1.ketabpezeshki. Then 1.UNIT 3 162 Dosage Calculations The Formula Method D × Q=x H 4.2 g) three places to the right: 1. 000 40 = = 8 tabl a et es 500 51 ANSWER: 8 tablets Dimensional Analysis 4g 1 t ablet 1.2 g to mg. 200 mg 2 = = 2 taabl b ets 1 1 600 mg ANSWER: 2 tablets in two divided doses or 1 tablet each dose Dimensional Analysis 1.200 2 x= 1. 000 mg = 600 0 mg 1g 2 1.indd 163 www. 200 mg ×1= x 600 mg 2 1.200 2 200 = 600 ×1 1 600 2 = = 2 tabl a ets 1 ANSWER: 2 tablets in divided doses or 1 tablet each dose = (021) 66485438 66485457 LWBK914-C08_p147-171.com 07/11/11 11:36 AM . 000 mg = 600 mg 1g × 1 ( tablet) 1.2 ×11 ( tabl ablet) 1. 000 1.200 mg : x 600x 0 = 1.2 g 1 t bl 1.CHAPTER 8 Oral Dosage Calculations 163 Ratio and Proportion 600 mg : 1 tablet = 1.2 g = × 1.ketabpezeshki. 200 = 2 tabl a ets 1 600 ANSWER: 2 tablets in 2 divided doses or 1 tablet each dose The Formula Method D ×Q = x H 1. Equivalent: 1 gr = 60 mg COMPLETE THE 1 gr : 60 mg = 1/4 gr : x mg PROPORTION: x = 1/4 × 60 SOLVE FOR X: 1 × 60 = 15 4 x = 15 mg (021) 66485438 66485457 LWBK914-C08_p147-171.com 07/11/11 11:36 AM . EXAMPLE: : morphine sulfate gr 1/4 Have: morphine sulfate 10-mg tablets Give: _____ tablet(s) To use ratio and proportion.ketabpezeshki. use the equivalent and convert to the available system.164 UNIT 3 Dosage Calculations Dosage Calculations for Medications in Different Systems R U L E When the desired and available drug doses are in different systems: Convert to the available system. write down what you know in a fraction or colon format. and use ratio and proportion or the Formula Method to calculate dosages. select the equivalent value. Milligrams are available. CONVERT TO M SAME SYSTEM: C Change gr 1/4 to mg. Use a conversion factor for dimensional analysis.indd 164 www. com 07/11/11 11:36 AM .indd 165 www.CHAPTER 8 Oral Dosage Calculations 165 Ratio and Proportion 10 mg : 1 tablet = 15 mg : x 10x 0 = 15 3 15 3 x= = = 1 1 2 tabl a ets 10 2 2 ANSWER: 1½ tablets The Formula Method D ×Q = x H 15 mg ×1= x 10 mg 3 x= 15 mg 3 = = 1 1 2 tabl a ets 10 1 mg 2 ANSWER: 1½ tablets Dimensional Analysis gr 1 4 = = ggr 1 × 1 1 tabl a et 60 mg = 10 mg gr 1 4 × 1( 4 ×1 1 tabl a et 60 mg = 10 mg gr 1 ) 60 10 ×1 3 = = 1 1 2 taabl b ets 2 3 = 15 2 10 ANSWER: 1½ tablets (021) 66485438 66485457 LWBK914-C08_p147-171.ketabpezeshki. Have: 2.d. 4. 8. t.d. : 160 mg daily Have: 40-mg tablets Give _______ tablet(s).indd 166 www. : 7.5-mg tablets Give _______ tablet(s). (021) 66485438 66485457 LWBK914-C08_p147-171. : 150 mg Have: 300-mg tablets Give _______ tablet(s). : 1. 5. 7. 2. : 75 mg Have: 15 mg per mL Give _______ mL. : 100 mg every 4 to 6 hr. as needed Have: 50-mg tablets Give _______ tablet(s) for each dose. : 20 mg Have: 10 mg per 5 mL Give _______ mL.i. 3. 6.com 07/11/11 11:36 AM .ketabpezeshki.i.166 UNIT 3 Dosage Calculations PRACTICE PROBLEMS 1. : 25 mg Have: 50-mg tablets Give tablet(s).500 mg Have: 500 mg per 5 mL Give _______ mL.5 mg t. The prescribed dose is 3 teaspoons. (021) 66485438 66485457 LWBK914-C08_p147-171.ketabpezeshki. A medication is on hand in a syrup (2 mg per mL). : 0. does it seem logical that the patient should be awakened during the night for his medication? _______ Yes or No? 11. 12. Since the suspension was ordered every 8 hr.CHAPTER 8 9. Critical Thinking Check Refer to question 10. Critical Thinking Check Refer to question 9. Oral Dosage Calculations 167 : 4 g to be taken in four equally divided doses Have: 500-mg tablets Give tablet(s) each dose.5 g every 8 hr Have: 250 mg per teaspoon Give mL. does it seem logical that one 500-mg tablet would be given? _______ Yes or No? 10.indd 167 www. Give mL.com 07/11/11 11:36 AM . which would be equal to mg. If 5 g were ordered in five divided doses. The initial dose of 125 mg for 3 days requires giving teaspoon(s) each day for a total of mL over 3 days. A drug is on hand in a liquid as 250 mg per 5 mL. ketabpezeshki. The nurse should give tablets.0015 g. The nurse should give mL. The drug was available as 0.8 g of a liquid medication. A physician prescribed 200 mcg of a medication for vertigo. The medication was available as 2. (021) 66485438 66485457 LWBK914-C08_p147-171. The physician prescribed 100 mg of a drug that was available in 40-mg tablets. The drug was available in a strength of 200 mg per mL.6 mg per mL. A physician prescribed 20 mg of syrup to be administered every 4 hr for pain. After 72 hr. A physician prescribed 60 mg of a diuretic. 19. The physician prescribed 7. A medication is on hand in a transdermal patch containing 0.168 UNIT 3 Dosage Calculations 13.5-mg tablets. mg remain. The system delivers 0. once daily. A physician prescribed 0.com 07/11/11 11:36 AM . 15. The nurse should administer mL. The mediation was available as 15 mg per tablet. 17. The nurse should give mL q4h.5 mg of a drug.indd 168 www. The medication was available as 0. The nurse should give mL. A physician prescribed 0.5 mg over 72 hr.6 mg per mL. 16. The nurse should give tablets. 14. 18. The drug was available as 50 mg per 5 mL. 20. The nurse should give tablets.4 mg of a medication for nutritional deficiency. : 1. : 300 mg Have: 100-mg tablets Give tablet(s). 4. : gr 1/2 Have: 15-mg tablets Give tablet(s).2 g Have: 50-mg tablets Give tablet(s).ketabpezeshki. 5. 2. 6.3-mg tablets Give tablet(s).com 07/11/11 11:36 AM .End of Chapter Review Solve the following problems: 1. : 30 mg daily Have: 10-mg tablets Give tablet(s). 3. : gr 1/200 Have: 0.5 g daily Have: 250 mg per 5 mL Give mL. 169 (021) 66485438 66485457 LWBK914-C08_p147-171.indd 169 www. : 0. 25-mg tablets Give tablet(s). Have: 10 mg per mL Give teaspoon(s) for each dose. The tablet is available as 500 mg.4-mg tablets Give tablet(s). : 5 mg Have: 1.indd 170 www. : gr 1/4 four times a day Have: 15-mg tablets Give tablet(s) per dose for a total of tablet(s) daily. : gr 1/4 Have: 10 mg per 5 mL Give mL. : 0. 8.ketabpezeshki.170 UNIT 3 Dosage Calculations 7. 12. three times a day. 13.1 g Have: 100-mg tablets Give tablet(s). 14.5 g daily in three equal doses. : 1.d. (021) 66485438 66485457 LWBK914-C08_p147-171.i. : gr 1/150 Have: 0. 9. The nurse would give mg. : 100 mg q.com 07/11/11 11:36 AM . 11. 10. 500 mg per tablet. : 20 g Have: 30 g in 45 mL Give ounce(s). i. Critical Thinking Check Refer to question 16. : 2.4 g daily for rheumatoid arthritis Have: 600-mg tablets Give tablet(s) a day. would you expect the patient to receive the same number of pills in 24 hr? ________Yes or No? 17. : 500 mg Have: 0. rather than every 6 hr.com 07/11/11 11:36 AM . for 2 weeks Have: 2. If the drug was ordered q.indd 171 www.ketabpezeshki. Critical Thinking Check Refer to question 17. Does it seem logical that 1 g of the drug could also be prescribed based on the available dosage? _______ Yes or No? Additional practice problems to enhance learning and facilitate chapter comprehension can be found on http://thePoint.25 g per 5 mL Give mL or teaspoon(s). : 10 mg daily. (021) 66485438 66485457 LWBK914-C08_p147-171.CHAPTER 8 Oral Dosage Calculations 171 15. 16.5-mg tablets Give tablets daily.lww. equally divided over 6 hr.d.com/Boyer8e. every 6 hr. and use). 172 (021) 66485438 66485457 LWBK914-C09_p172-190. and prefilled cartridges and syringes). the Formula Method. • Distinguish among the different types of syringes: hypodermic. • Identify the parts of a syringe. gauge. U-100. and dimensional analysis.CHAPTER 9 Parenteral Dosage Calculations LEARNING OBJECTIVES After completing this chapter. vials.ketabpezeshki. • Describe the differences in needles (length. and U-50 insulin. • Calculate parenteral medication dosages using ratio and proportion. tuberculin. • Distinguish among three types of parenteral injection: intradermal.com 07/11/11 1:20 PM . • Explain how parenteral medications are supplied (ampules. you should be able to: • Define the term parenteral as it refers to medication administration. and intramuscular. • Interpret a parenteral drug label. subcutaneous.indd 172 www. Luer-Lok syringes have a tip that syringe-specific needles twist into. and Needles Packaging. subcutaneously (SQ).ketabpezeshki. intradermally (ID). It is used when the oral route would be ineffective (delayed absorption time. Syringes. Medications can be administered intramuscularly (IM). vials (small. a plunger. 11. or patient’s inability to swallow) or the drug needs to be quickly absorbed. or in prefilled cartridges and syringes that contain a single drug dose. non–Luer-Lok syringes have a tip that needles (021) 66485438 66485457 LWBK914-C09_p172-190.CHAPTER 9 Parenteral Dosage Calculations 173 T he term parenterall refers to any route of drug delivery other than gastrointestinal.com 07/11/11 1:20 PM . Remember: Needle precautions must always be followed when administering parenteral medications. Syringes have three parts: a barrel with milliliter (mL) calibrations. sealed containers that hold a single dose). drug interactions. and insulin (U-100 and U-50. and 14. glass or plastic bottles with a rubber tip and cover). are covered in Chapters 10. including IV piggyback (IVPB) and IV push. Intravenous therapies.indd 173 www. Parenteral medications are commonly supplied in liquid or solution form and packaged in ampules (small. and intravenously (IV). Insulin is covered in Chapter 12 and heparin in Chapter 13. Syringes. glass. and a tip. Reconstitution of powders for injections is presented in Chapter 15. Pediatric calculations are covered in Chapter 14. low dose). There are three kinds of syringes: hypodermic. Packaging. tuberculin. Preparations that come in a powder form must be reconstituted according to the manufacturer’s directions. 1 mL) and hundredths (0. and (c) use the top of the black ring to measure the correct amount. (021) 66485438 66485457 LWBK914-C09_p172-190. with longer lines indicating 0. Hypodermic and Tuberculin Syringes.0 mL. (b) draw the medication into the barrel. Most injectable medications are given in a 3-mL syringe unless the dosage can easily be measured in a 1-mL syringe. whereas others are needleless (IV use).1 A.indd 174 www.1 for an example of a standard. a picture of a needless port is given in Appendix L. Markings on the 1-mL narrow tuberculin syringe (commonly used for solutions less than 1 mL) can be found in tenths (0.2 and 9. Luer-Lok hypodermic syringe and a 1-mL tuberculin syringe. to avoid errors. See Figures 9.1-mL increments. B.01 mL). It is essential that you read these calibrations accurately so that you give the correct amount of medication. Tuberculin syringe. Smaller syringes still indicate minims but are not used frequently. 3-mL syringe is marked on one side in 0. 3-mL. The standard.5 mL and 1. Standard 3-mL Luer-Lok syringe. See Figure 9.3 for examples of labels for two different parenteral drug preparations.174 UNIT 3 Dosage Calculations FIGURE 9. always remember to (a) hold the syringe at eye level. When checking the liquid medication in the syringe.ketabpezeshki. Some syringes have a safety glide (which covers the needle after use).com 07/11/11 1:20 PM . slip into. (Courtesy of GlaxoSmithKline.) (021) 66485438 66485457 LWBK914-C09_p172-190. which is no longer used very often in the hospital.) Insulin syringes.3 Kefzol. It is used in home care. marked every 1 unit). the larger is the diameter. Needles are distinguished by their length (inches) and their gauge (width or diameter) and have different uses. IN. A U-30 syringe is being phased out but may be used in the home.3 Needles. a 14-gauge IV needle has a larger diameter than a 27-gauge needle FIGURE 9. The lower the gauge number. Two insulin syringes are shown in Figure 12.ketabpezeshki. PA. Philadelphia. is administered using a U-100 syringe (up to 1-mL volume. (Courtesy of Eli Lilly Company.CHAPTER 9 Parenteral Dosage Calculations 175 FIGURE 9. supplied in quantities of 100 units per mL.indd 175 www. Indianapolis. For example.com 07/11/11 1:20 PM . lowdose syringe (up to 0. marked every 2 units) or a U-50.2 Ancef.5-mL volume. Insulin syringes are only used for insulin! Insulin. See Table 9. 2. subcutaneous tissue above the muscle. in Appendix D.176 UNIT 3 Dosage Calculations Table 9. 4. tuberculin skin testing. Refer to Appendix E. Common sites: inner surface of forearm and upper back below the scapula.ketabpezeshki. Small amounts of drugs (0.1 Needle Gauge and Length for Different Types of Injection Type of Injection Needle Gauge Needle Length (inches) Intradermal Intramuscular Intravenous Subcutaneous 25 18 to 23 14 to 25 23 to 28 3/8 to 5/8 1 to 3 1 to 3 5/8 to 7/8 used for intradermal injections.1 mL to 0. Small amounts of drugs (0. Refer to the picture Administering an Intradermal Injection. • Subcutaneous Injections: under the skin or dermis into the fibrous.1 for an example. The average dose is 0. The subcutaneous route is used for: 1.com 07/11/11 1:20 PM . Insulin (021) 66485438 66485457 LWBK914-C09_p172-190.indd 176 www. 3. 2. Solutions that are nonirritating and slowly absorbed. and local anesthesia.1 mL. Allergy testing.5 mL). The intradermal route is used for: 1. Types of Injections • Intradermal Injections: into the dermis (under the outer layer of skin or epidermis).5 mL to 1 mL). in Appendix F.com 07/11/11 1:20 PM . Dosage Calculations for Medications in the Same System and the Same Unit of Measurement To calculate parenteral dosage problems.indd 177 www.ketabpezeshki. Refer to the picture Administering an Intramuscular Injection. using one of the three calculation methods. weight. Tetanus toxoid • Intramuscular Injections: into the body of a striated muscle. R U L E Whenever the prescribed or desired and available drug dosages are different but in the same system and the same unit of measurement: Use one of three methods to calculate dosages. Drugs that are given in large volume. Refer to Chapter 8 for a quick review of these three methods. or dimensional analysis can be used.CHAPTER 9 Parenteral Dosage Calculations 177 3. Drugs that require a rapid rate of absorption. 3. Ratio and proportion. Drugs that would be ineffectively absorbed in the gastrointestinal tract. follow the same rules that you used for oral dosage calculations. (021) 66485438 66485457 LWBK914-C09_p172-190. or special considerations before administering parenteral medications. Heparin 4. The intramuscular route is used for: 1. Remember to follow any guidelines regarding patient age. the Formula Method. 2. ketabpezeshki.2 mL (021) 66485438 66485457 LWBK914-C09_p172-190.com 07/11/11 1:20 PM .2 mL Dimensional Analysis 1 mg × 1 mg = 1 mL 5 mg × 1 mL 1 1 (mL) = 5 mg 5 1 = 0 2 mL 5 ANSWER: 0.indd 178 www.2 mL 5 ANSWER: 0.2 mL The Formula Method D ×Q = x H 1 mg ×1= x 5 mg 1 ×11 5 0.2 mL ANSWER: 0.178 UNIT 3 EXAMPLE #1: Dosage Calculations : 1 mg Have: 5 mg per mL Give: _____ mL Ratio and Proportion 5 mg : 1 mL = 1 mg : x mL 5x = 1 x= 1 × 1 mL = 0. CHAPTER 9 EXAMPLE #2: Parenteral Dosage Calculations 179 : 300 mg Have: 150 mg per mL Give: _____ mL Ratio and Proportion 150 mg : 1 mL = 300 mg : x mL 150x 0 = 300 2 x= 300 2 = = 2 mL 150 1 1 ANSWER: 2 mL The Formula Method D ×Q = x H 300 ×1 = x 150 2 300 2 = ×1 150 1 1 2 mL ANSWER: 2 mL Dimensional Analysis 300 mg = × 1 mL 150 mg 300 mg × 1 mL 300 × 1 (mL) = 150 mg 150 2 = 300 2 = =2 150 1 1 ANSWER: 2 mL (021) 66485438 66485457 LWBK914-C09_p172-190.ketabpezeshki.com 07/11/11 1:20 PM .indd 179 www. ketabpezeshki.77 50 10 10 ANSWER: 0.indd 180 www.com 07/11/11 1:20 PM .7 mL ANSWER: 0.180 UNIT 3 EXAMPLE #3: Dosage Calculations : 35 mg Have: 50 mg per mL Give: _____ mL Ratio and Proportion 50 mg : 1 mL = 35 mg : x 50x 0 = 35 7 35 7 = = 0 7 mL 50 10 10 x= ANSWER: 0.7 mL (021) 66485438 66485457 LWBK914-C09_p172-190.7 mL Dimensional Analysis 35 mg = × 1 mL 50 mg 35 mg × 1 mL 35 × 1 (mL) = 50 mg 50 7 = 35 7 = = 0.7 mL Formula Method D ×Q = x H 35 ×1 = x 50 7 35 7 = ×1 50 10 10 0. EXAMPLE: : 0. move the deecimal point (0.ketabpezeshki.25 mg) three places to the right.25 mg to mcg.CHAPTER 9 Parenteral Dosage Calculations 181 Dosage Calculations for Medications in the Same System but Having Different Units of Measurement R U L E Whenever the prescribed or desired and available drug dosages are in the same system but in different units of measurement: Convert to like units. change to the smaller unit. and use one of three methods to calculate dosages.com 07/11/11 1:20 PM .indd 181 www.25 mg Have: 500 mcg per 2 mL Give: _____ mL CONVERT TO LIKE UNITS: Too convert 0. Then 0. Remember to use a conversion factor if you use dimensional analysis.25 mg = 250 mcg. Ratio and Proportion 500 mcg : 2 mL = 250 mcg : x mL 500x 0 = 500 (250 × 2) x= 500 1 500 1 = 1 mL ANSWER: 1 mL (021) 66485438 66485457 LWBK914-C09_p172-190. com 07/11/11 1:20 PM . Use one of three methods to calculate dosages. write down what you know in a fraction or ratio format. 000 500 = = 1 mL 500 × 1 500 1 × 2 mL 1. (021) 66485438 66485457 LWBK914-C09_p172-190.ketabpezeshki. Use a conversion factor if you are using dimensional analysis. and use ratio and proportion to solve for x.25 2 (mL) . select the equivalent value. 000 mc mcgg = 500 mc mcgg 1 mg 1 ANSWER: 1 mL Dosage Calculations for Medications in Different Systems R U L E Whenever the prescribed or desired and available drug dosages are in different systems: Convert to the same system (use available system).25 25 g 0.indd 182 www.182 UNIT 3 Dosage Calculations The Formula Method D ×Q=x H 250 ×2= x 500 1 250 mcg 2 500 mcg = 1 ×2 2 1 mL ANSWER: 1 mL Dimensional Analysis 0 25 = = g × 2 mL 500 mcg 0. EQUIVALENT: grr 1 = 60 mg 183 COMPLETE THE gr 1 : 60 mg = gr 1 1 : x mg PROPORTION: 2 1 1 × 60 2 3 30 x= × 60 = 90 mg 21 SOLVE FOR X : 1x Ratio and Proportion 60 mg : 1 mL = 90 mg : x mL 60x 0 = 90 3 x= 90 3 = = 1 5 mL 60 2 2 ANSWER: 1.5 mL The Formula Method D ×Q=x H 90 ×1= x 60 3 90 3 = = 1 5 mL 60 2 2 ANSWER: 1. b.com 07/11/11 1:20 PM . b.ketabpezeshki.CHAPTER 9 Parenteral Dosage Calculations EXAMPLE: : gr 1½ IM.indd 183 www.d.i.d.5 mL (021) 66485438 66485457 LWBK914-C09_p172-190.i. Have: 60 mg per mL Give: _____ mL. 5 mL Penicillin Penicillin is one of a limited number of medications that is available in units per mL as well as mg per mL. or dimensional analysis.com 07/11/11 1:20 PM .000 units per 1.000 units of penicillin G procaine to be administered every 12 hr (q12h). and use one of three methods to calculate dosages. When calculating dosages for penicillin. the Formula Method. you can use ratio and proportion. Penicillin G procaine is available as 600. Insulin (covered in Chapter 12) and heparin (covered in Chapter 13) are two other common medications that you will need to become familiar with.5 1 (mL L ) 60 = 60 × 1 = = gr 1 5 90 60 × 3 2 = 1 5 mL ANSWER: 1. EXAMPLE: A patient is prescribed 300.184 UNIT 3 Dosage Calculations Dimensional Analysis gr 1 5 × 1 mL 60 mg 1 mL 60 mg = 60 mg gr 1 1.indd 184 www.2 mL.ketabpezeshki. (021) 66485438 66485457 LWBK914-C09_p172-190. R U L E To prepare penicillin for injection: Check the prescribed or desired units to be given. 000 6 62 2 1 × 1.2 ( ) 600.6 mL Dimensional Analysis 300. 000 × 1.22 mL = 0 6 mL 2 ANSWER: 0.indd 185 www.com 07/11/11 1:20 PM .000 : x mL 600. 000 36 6 = = = 0 6 mL 600. 000 units units 36 = 300.ketabpezeshki.6 mL The Formula Method D ×Q=x H 3 1 300.2 600.2 mL = 300. 000 uni units ts = 1.000 units : 1.CHAPTER 9 Parenteral Dosage Calculations 185 Ratio and Proportion 600.2 mL 600.000 × 1.6 mL (021) 66485438 66485457 LWBK914-C09_p172-190. 000 units 300. 00 0000 60 = 36 6 = = 0 6 mL 60 10 10 6 ANSWER: 0.000x 0 = 300.2 360. 000 600. 000 = 600.000x 0 = 360. 000 units = 1. 000 3 1 = = 600. 000 60 60 10 10 ANSWER: 0.000 36 x= 6 360. The nurse should give _____ mL a day for 5 days. Give 0.3 g of a drug that is available as 100 mg per mL for injection.0 mg per mL. The drug is available for injection as 10 mg per mL.r. 2.End of Chapter Review Complete the following problems: 1. The nurse should give _____ mL. p. 4.002 g of a drug. 3. for severe intestinal malabsorption. The nurse should draw up _____ mL. The medication is available as 5 mg per mL.. The nurse should give _____ mL every 8 hr. The injection is on hand as 1. Give 2 mg of a drug. Give 0.com 07/11/11 1:20 PM .indd 186 www. 6.ketabpezeshki. 186 (021) 66485438 66485457 LWBK914-C09_p172-190. for 5 days. The nurse should give _____ mL. every 4 to 6 hr. Give 60 mg of a diuretic IM in three equally divided doses every 8 hr for 2 days. IM. The nurse should give _____ mL every 4 to 6 hours as needed. Give 10 mg of a drug that is available as 5 mg per mL.n. Give 4 mg of a drug that is available as 5 mg per mL. 5. per day. of a drug preoperatively to induce drowsiness.5 mg of a medication that is available in a vial as gr 1/150 per 1. Give 1 mg of a drug every 4 to 6 hr for analgesia. Give 30 mg of a diuretic.0 mg per mL. The nurse should give _____ mL.5 mg of a drug. 9. Give 50 mg of a medication that is available in vials containing gr i per mL. 11. (021) 66485438 66485457 LWBK914-C09_p172-190. 12. p. 10. Give 6 mg of a drug. The medication is available for injection as 2. The physician requested that a patient receive 1. IM. The nurse should give _____ mL every 3 to 4 hr.CHAPTER 9 Parenteral Dosage Calculations 187 7. The drug is available as 5 mg per mL. The medication is available as 2 mg per mL. Give 3 mg.r. Give 35 mg.indd 187 www. The nurse should give _____ mL every 4 to 6 hr.0 mL. The drug is available as 4 mg per mL. 13. 8. 14. IM. of a drug that is available for injection as 50 mg per mL. weekly. The drug is available as 40 mg per mL. The nurse should give _____ mL.n.com 07/11/11 1:20 PM . The nurse should give _____ mL every week. every 3 to 4 hr as needed for pain. IM. The nurse should give _____ mL. The nurse should give _____ mL.ketabpezeshki. The nurse should give _____ mL. Give 0. The nurse should give _____ mL. 21. (021) 66485438 66485457 LWBK914-C09_p172-190. The medication is available as 15 mg per mL. Give 0. prior to an operative procedure. The drug is available as 50 mcg per mL. IM. as needed. 20. The nurse should give _____ mL. Critical Thinking Check Because the available medication strength (15 mg per mL) is a stronger drug concentration than the prescribed medication (gr 1/5). every 4 to 6 hr. Give 50 mg.188 UNIT 3 Dosage Calculations 15 Give gr 1/5.1 mg of a drug. The nurse should give _____ mL. The nurse should give _____ mL. The nurse should give _____ mL.2 mg per mL. does it seem logical that greater than 1 mL would be given? ________ Yes or No? 16 Give 6 mg of a drug. The drug is available as 100 mg per 2 mL. IM. q6h. Give 25 mg. of a drug preoperatively. IM. The nurse should give _____ mL.ketabpezeshki. Give 500 mcg. every 4 to 6 hr for severe pain. 18. of a drug that is available as 25 mg per mL. The nurse should give _____ mL. Give 0.15 mg IM of a drug that is available as 0. IM. of a drug that is available as 1 mg per mL.com 07/11/11 1:20 PM . 19. 17. The medication is available as 10 mg per mL for injection.indd 188 www. as a single dose.com 07/11/11 1:20 PM . The nurse should give _____ mL. Give 90 mg of a drug. (021) 66485438 66485457 LWBK914-C09_p172-190. Give 0.75 grams per 3 mL. IM. Give 0. Bicillin is packaged as 600. Give _____ mL. of a drug that is available as 2 mg per mL. 28. Give 30 mg. of a drug that is available as 30 mg per mL.05 mg of a drug that is available as 100 mcg per 5 mL. 27. 26. The nurse should give _____ mL. The nurse should give _____ mL.000 units per mL. The physician prescribed Crysticillin 600.indd 189 www.25 mg of a drug that is available as 250 mcg per mL. 24. Give _____ mL.ketabpezeshki. Give _____ mL. 23. Give 0. IM. Give gr 1/4.CHAPTER 9 Parenteral Dosage Calculations 189 22. q12h for 5 days. Crysticillin is available in a 12-mL vial labeled 500. IM.000 units of Bicillin. The nurse should give _____ mL per dose. 31. Give 4 mg. that is available as 120 mg per 2 mL.4 g of a drug that is available as 500 mg per 5 mL. 29. 30. q6h.000 units. Give _____ mL. The physician prescribed 300. Give 250 mg of a drug that is available as 0.000 units per mL. The nurse should give _____ mL. of a drug that is available as 20 mg per mL. IV. The nurse should give _____ mL. q6h. 25. lww.000 units. The physician prescribed penicillin G potassium 125. q12h. as a single injection.com 07/11/11 1:20 PM . The nurse should give _____ mL. Critical Thinking Check Would it seem logical to give a dosage of 1. The medication is available in solution as 250.indd 190 www.190 UNIT 3 Dosage Calculations 32. 33.com/Boyer8e. (021) 66485438 66485457 LWBK914-C09_p172-190.2 million units was prescribed. Penicillin G benzathine 1. IM. The nurse should give _____ mL every 12 hr.ketabpezeshki. IM. The drug is available as 300.000 Units per mL.000 units per mL.2 M units as a single injection? ________ Yes or No? Additional practice problems to enhance learning and facilitate chapter comprehension can be found on http://thePoint. • Distinguish among infusion pumps. • Calculate flow in mL per hr for manual and electronic regulation when the infusion is less than 1 hr.com 07/11/11 11:38 AM . and a patient-controlled analgesia (PCA) pump. syringe pumps.ketabpezeshki. • Calculate rate of infusion of an intravenous (IV) push.CHAPTER 10 Intravenous Therapy LEARNING OBJECTIVES After completing this chapter. • Describe intermittent intravenous fluid therapy (IV piggyback [IVPB] and IV push). • Calculate infusion time in hours and minutes. you should be able to: • Explain the purpose of intravenous therapy (fluids and medicine). • Calculate flow rate in milliliters per hour (mL per hr) for gravity and pump infusion. • Calculate flow rate using the Quick Formula with a constant factor. • Identify various infusion sets and tubing.indd 191 www. • Calculate flow rate in drops per minute (gtt per min) using the Standard Formula and dimensional analysis. 191 (021) 66485438 66485457 LWBK914-C10_p191-218. UNIT 3 192 Dosage Calculations I ntravenous (IV) fluid therapy involves the administration of water, nutrients (e.g., dextrose, protein, fats, and vitamins), electrolytes (e.g., sodium, potassium, and chloride), blood products, and medications directly into a vein. Intravenous fluids can be continuous or intermittent (IV push and IV piggyback [IVPB]). Continuous infusions are for fluid replacement or fluid maintenance to treat disorders like dehydration, malnutrition, and electrolyte imbalance. Blood and blood products are administered with special Y-type tubing according to highly specific protocols and institutional requirements. Parenteral nutrition is nutritional supplementation given IV when the oral or enteral route cannot be used. Parenteral nutrition is given through a central venous access device (TPN) or a peripheral line (PPN). The same principles guiding IV therapy are used for parenteral therapy. Enteral tube feeding via a pump is covered in Chapter 15. This chapter will discuss the basic information about types of equipment, fluids, and infusion calculations (drop factors, drip rates, flow rates, and infusion time). Special IV calculations used in critical care situations are treated in Chapter 11. Key Terms • Drip rate: the number of drops entering the drip chamber based on the size of the IV tubing (gtt per min). • Drop factor: the size of the drop entering the drip chamber based on the size of the IV tubing. (021) 66485438 66485457 LWBK914-C10_p191-218.indd 192 www.ketabpezeshki.com 07/11/11 11:38 AM CHAPTER 10 Intravenous Therapy 193 Drop factors range from 10 gtt per mL to 60 gtt per mL. • Flow rate: the rate in mL per hr given over time. • Infusion time: the time in hours and minutes that it takes for an IV to completely infuse. • Titration: adjustment of the IV medication dosage within prescribed parameters to achieve a desired effect. Intravenous Fluids A physician’s order for intravenous fluid therapy must include the name and amount of the IV solution, any medication that should be added, and the time period for infusion (e.g., q8h, at 50 mL per hr, or in terms of mcg/kg/min, mcg/kg/hr, or mg per min) for critical care. The physician’s order is usually written as mL per hr to be infused (flow rate). The flow rate is regulated manually by straight gravity, by volume control, or via an electronic infusion device. Intravenous fluids are prepared in sterile, plastic bags (most common) or glass bottles, and the quantity of solution ranges from 50 mL to 1,000 mL. Solutions are clearly labeled. Standard abbreviations are used for the type and concentration of IV solutions: D (dextrose), NS (normal saline), RL (Ringer’s lactate), S (saline), and W (water). Numbers refer to the percentage of the solution strength. For example, D5W refers to 5% dextrose (solute) dissolved in a water solution (usually 500 mL to 1,000 mL). Normal saline is a 0.9% sodium chloride solution (900 mg per 100 mL). Percentages less than 0.9% are equivalent to 1/3 (0.33%) or 1/2 (021) 66485438 66485457 LWBK914-C10_p191-218.indd 193 www.ketabpezeshki.com 07/11/11 11:38 AM 194 UNIT 3 Dosage Calculations (0.45%). Ringer’s lactate is an isotonic solution that replenishes fluids and electrolytes. Review the types of IV fluids and abbreviations in Table 10.1 and interpret the following sample physician orders: • Administer 1,000 mL of D5W at 125 mL per hr. • Administer 1,000 mL of 0.9% NS every 12 hr for 2 days. Table 10.1 Commonly Prescribed Intravenous Fluids Fluid Abbreviation 0.9% Sodium chloride solution 0.45% Sodium chloride solution 0.25% Sodium chloride solution 5% Dextrose in water NS 1/2 NS 1/4 NS 5% D/W D5W 10% D/W D10W D5 1/2NS 10% Dextrose in water 5% Dextrose in 0.45% sodium chloride solution Dextrose with Ringer’s lactate solution Lactated Ringer’s solution Plasma volume expanders Dextran Albumin Hyperalimentation Total parenteral nutrition Partial parenteral nutrition Fat emulsions Intralipid (021) 66485438 66485457 LWBK914-C10_p191-218.indd 194 D/RL RL TPN PPN www.ketabpezeshki.com 07/11/11 11:38 AM CHAPTER 10 Intravenous Therapy 195 • Administer 500 mL of D10W at 83 mL per hr. • Administer 100 mL of RL over 4 hr at 25 mL per hr. Intravenous Infusion Sets and Lines Intravenous fluids are administered via an IV infusion set. The set consists of IV fluids in a sterile, plastic bag or glass bottle connected by IV tubing. An IV set includes a drip chamber with spike, one or more injection ports (access for IVPB and IVP drugs), a filter, and a slide or roller clamp used to regulate the drops per minute. The primary IV line is either a peripheral line, usually inserted into the arm or hand, or a central line, inserted into a large vein in the chest (subclavian) or neck (jugular). Secondary IV lines, also known as IV piggyback (IVPB), are used for intermittent, smaller-quantity infusions (e.g., a medication in 50 mL to 100 mL of fluid) and are attached to the primary line through an injection port. A peripherally inserted central catheter (PICC line) is threaded into the superior vena cava through a vein in the arm. Infusion Devices IV fluids can be regulated by several different electronic infusion devices: pumps, syringe pumps, patient-controlled analgesia (PCA) pumps, and a balloon device used in home care. Infusion pumps are used when small amounts of fluids/medications must be given over a strictly regulated period of time. The infusion pump consistently exerts pressure against (021) 66485438 66485457 LWBK914-C10_p191-218.indd 195 www.ketabpezeshki.com 07/11/11 11:38 AM 196 UNIT 3 Dosage Calculations the resistance of the tubing or the fluid at a preselected rate. Pumps are not gravity dependent! A pump delivers a set quantity (mL per hr); however, pumps can be dangerous because they continue to infuse even in the presence of infiltration or phlebitis. Infusion pumps can also regulate IVPB infusions by overriding the primary IV line. There are standard pumps and more complex ones that are used for specialty units. A syringe pump (a syringe filled with medication and attached to a pump) regulates medications that must be given at a very low rate over 5 min to 20 min. A PCA pump, used by patients for pain management (the patient pushes a control button to self-administer the medication), delivers a set amount of a narcotic in a prefilled syringe over a specified time period. As a safety measure, there is a time interval when no medication can be delivered even if the patient pushes the button. The RN is responsible for the PCA loading dose, the narcotic injector vial, and the pump setting. To set an electronic infusion pump, you must enter the quantity of fluid to be given (mL) and the milliliters per hour (mL per hr). To set a pump used in critical care units, you also enter information such as medication name, dosage concentration, fluid quantity, and the patent’s weight. The medication may also be titrated to the patient’s blood pressure. Infusion pumps are used whenever possible. However, when IVs are administered by gravity flow, you need to know the drop factor (drops per milliliter) in order to calculate the drip rate (gtt per min). See Figure 10.1. (021) 66485438 66485457 LWBK914-C10_p191-218.indd 196 www.ketabpezeshki.com 07/11/11 11:38 AM CHAPTER 10 Intravenous Therapy 197 FIGURE 10.1 Electronic infusion pump. (From Taylor, C., Lillis, C., LeMone, P., and Lynn, P. [2008]. Fundamentals of nursing. The art and science of nursing care [6th ed.]. Philadelphia: Lippincott Williams & Wilkins.) Calculate Intravenous Fluid Administration The physician’s IV order always includes the quantity of solution (mL) to be given and the time period, either in hours (e.g., q8h, q12h) or in terms of amount (e.g., 100 mL per hr). The nurse is responsible for regulating the infusion either by gravity or programming the milliliters per hour on the pump. The remainder of this chapter will cover what you need to know to: (021) 66485438 66485457 LWBK914-C10_p191-218.indd 197 www.ketabpezeshki.com 07/11/11 11:38 AM 198 UNIT 3 Dosage Calculations • Calculate infusion time in hours and minutes. • Calculate flow rate in milliliters per hour for either gravity infusion or an infusion device. • Calculate drops per minute (gtt per min) for gravity infusion (the drop factor of the IV tubing is needed). • Regulate the number of drops entering the drop chamber by using the roller clamp on the tubing to adjust the flow rate (count the number of drops for 1 min). Remember to always hold a watch up to the drip chamber at eye levell to accurately count the drops! • Set the electronic infusion pump by entering the total amount of milliliters to be infused and the milliliters per hour after connecting the IV fluids. The pump is set in mL L per hr. • Calculate drops per minute using the Quick Formula with a constant factor. • Calculate drops per minute for intermittent intravenous infusion. • Calculate infusion time for an IV push medication. Calculate Infusion Time in Hours and Minutes A simple one-step ratio (division) is all that is needed when total volume is known and milliliters per hour have been ordered. Always round off to the nearest tenth! Use this formula: Total volume ((mL orde r red) Milliliters per hour u (mL/hr / r) = Number of hours r to run r (021) 66485438 66485457 LWBK914-C10_p191-218.indd 198 www.ketabpezeshki.com 07/11/11 11:38 AM CHAPTER 10 Intravenous Therapy 199 Note: When the number of hours includes additional minutes, you need to round to the nearest tenth. Then multiply the part of an hour by 60 min to get the exact number of minutes. EXAMPLE #1: Th he patient is to receive 1,000 mL of D5W solution at 125 mL per hr. Total volume = Number of hours, mL/hr 1,000 mL 8 hr = = 8 hr 125 2 mL/hr 1 ANSWER: 8 hr EXAMPLE #2: Th he patient is to receive 1,000 mL of NS at 80 mL per hr. Total volume = Number of hours, r mL/hr 1,000 mL 12.5 hr = = 12.5 hr 80 mL/hr 1 ANSWER: 12½ hr, or 12 hr and 30 min (½ × 60 min = 30 min) Calculate Flow Rate in Milliliters per Hour for Gravity or Pump Infusions To calculate milliliters per hour, all you need to know is the total volume to be infused over time. When a pump is used, simply set the infusion rate at milliliters (021) 66485438 66485457 LWBK914-C10_p191-218.indd 199 www.ketabpezeshki.com 07/11/11 11:38 AM 000 1. which is basically simple division.200 UNIT 3 Dosage Calculations per hour after connecting the IV fluids. 000 mL = 166.6 mL per hr x= ANSWER: 167 mL per hr The Standard Formula Total volume ((mL) = mL/hr Total time (hr) 1. Note: When the infusion time is less than 1 hr. and start the infusion. Ratio and Proportion 1.indd 200 www. dimensional analysis. R U L E To calculate milliliters per hour: Use one of three methods to calculate dosages: ratio and proportion. include the conversion factor (60 min) in the calculation.ketabpezeshki.000 mL : 6 hr = x mL : 1 hr 6x = 1. For dimensional analysis.000 mL of lac- tated Ringer’s solution over a 6-hr period. you need to use total time in minutes.com 07/11/11 11:38 AM . or the Standard Formula (total volume divided by total time in hours). The patient should receive _____ mL per hr. EXAMPLE #1: A patient is to receive 1. 000 6 x = 166.6 mL/hr 6 ANSWER: 167 mL per hr (021) 66485438 66485457 LWBK914-C10_p191-218. indd 201 www. 000 30 1 = 100 mL/hr ANSWER: 100 mL per hr The Standard Formula Total volume ((mL) x (mL/hr h) = Total time (min ( ) 660 min 50 mL x (mL) = 30 min 60 min (021) 66485438 66485457 LWBK914-C10_p191-218.CHAPTER 10 Intravenous Therapy 201 Dimensional Analysis Because two factors are already given. 000 (mL) 1. Ratio and Proportion 50 mL : 30 min = x mL : 60 min (1 hr) 30x 0 = 3. 000 = = 166.com 07/11/11 11:38 AM . 1.ketabpezeshki.000 mL and the wanted quantity (x) is mL per hr.000 100 x= 3. The given quantity is 1.6 6 (h ) 6 167 mL or hr ANSWER: 167 mL per hr EXAMPLE #2: A patient is to receive 1 g of an antibiotic in 50 mL of NS over 30 min. all that is necessary is simple division. you need three pieces of information: • The total volume to be infused in milliliters • The drop factorr of the tubing you will use • The total time for the infusion in minutes or hours The flow rate of the IV solution as it passes through the drip chamber is determined by the drop (021) 66485438 66485457 LWBK914-C10_p191-218.com 07/11/11 11:38 AM .ketabpezeshki. 000 100 = = 100 mL/hr 30 1 1 ANSWER: 100 mL per hr Calculate Drip Rate or Drops per Minute To calculate drops per minute (gtt per min).indd 202 www.000 (50 × 60) 100 x= 3000 30 1 = 100 mL/hr ANSWER: 100 mL per hr Dimensional Analysis Two factors are already given. You need to include the conversion factor: 60 min = 1 hr.202 UNIT 3 Dosage Calculations 30x 0 = 3. 50 mL 60 min × 30 min 1 hr 50 (mL) 60 50 (mL) × 60 × = 30 1 (hr h) 30 × 1 (hr h) 100 = 3. Right: A drip chamber of an IV tubing for a macrodrip (gtt/mL varies). 15.CHAPTER 10 Intravenous Therapy 203 Microdrip Macrodrip FIGURE 10. See Figure 10. The drop factor is printed on the IV tubing package. The Table 10. It is either a macrodrip (10.com 07/11/11 11:38 AM . The microdrip contains a needle in the chamber to make the drops smaller. or 20 drops per min) or a microdrip (60 drops per min).ketabpezeshki. Several formulas and dimensional analysis can be used to calculate flow rate in drops per minute.indd 203 10 15 20 60 gtt gtt gtt gtt per per per per mL mL mL mL www. factor (drops per milliliter) of the tubing set.2.2 Common Drop Factors for IV Tubing Sets Macrodrop Microdrop (021) 66485438 66485457 LWBK914-C10_p191-218.2 and Table 10.2 Left: A drip chamber of an IV tubing for a microdrip (60 gtt/mL). Note: When a microdrip is used with a drop factor of 60. Note: When an IV order includes a medication.com 07/11/11 11:38 AM . if it runs at 35 mL per hr. simply prepare the medication as directed and then calculate the flow rate using one of the following formulas. The drop factor is 15 gtt per mL. usually the drug is already premixed.25 gtt/min t ANSWER: 31 gtt per min (021) 66485438 66485457 LWBK914-C10_p191-218. then the gtt per min is 35. The Standard Formula Total volume × Drop fact f or Total time (min ( ) = Dr Drops per minute ((gtt/min) x= EXAMPLE #1: A Administer 1. If the physician orders an IV to run at 75 mL per hr with a microdrip. the drops per minute will always equal the milliliters per hour.000 mL of D5W every 8 hr. The Standard Formula Total volume Drop fact f or Total time (min ( ) = Drrops o per minute 1. then the gtt per min is 75. If you need to add the drug.ketabpezeshki. 000 = 480 min (60 8) 480 = 31. 000 mL × 15 15.indd 204 www.204 UNIT 3 Dosage Calculations Standard Formula for gtt per min and dimensional analysis will be used. CHAPTER 10 Intravenous Therapy 205 Dimensional Analysis Total volume Drop r p fact f or 1 hr × × hr mL 60 min 1, 000 mL 15 ggtt 1 hr × × 8 hr 1 mL 60 min 1, 000 155 (gtt) × 1 8 1 60 ( i ) 15, 000 = = 31.25 gtt/min 480 ANSWER: 31 gtt per min EXAMPLE #2: A Administer 500 mL of 0.9% NS over 6 hr. The drop factor is 20 gtt per mL. The Standard Formula Total volume Drop fact f or = gtt/min t Total time (min ( ) 500 mL × 20 10, 000 = = 27.7 gtt/min 360 min 360 ANSWER: 28 gtt per min Dimensional Analysis Total volume Drop r fact f or 1 hr = = hr mL 60 min 500 mL 20 ggtt 1 hr × × 6 hr 1 mL 60 min (021) 66485438 66485457 LWBK914-C10_p191-218.indd 205 www.ketabpezeshki.com 07/11/11 11:38 AM 206 UNIT 3 Dosage Calculations 500 × 20 (gtt g ) × 1 10, 000 = 6 1 60 (min ( ) 360 = 27.7 gtt/mi t n ANSWER: 28 gtt per min EXAMPLE #3: A Administer 500 mL of a 5% solution of normal serum albumin over 30 min. The drop factor is 10. The Standard Formula Total volume Drop fact f or = gtt/min t Total time (min i ) 500 mL × 10 gtt/mL 5, 000 = 30 min 30 = 166.6 gtt/min ANSWER: 167 gtt per min Dimensional Analysis Total volume Drop r fact f or 1 hr = = hr mL 60 min 500 mL 10 ggtt 1 hr × × 0 5 hr 1 mL 60 min 500 × 10 (gtt g ) ×1 5, 000 = 0 5 × 1 60 ( i ) 30 = 166.6 gtt/min ANSWER: 167 gtt per min (021) 66485438 66485457 LWBK914-C10_p191-218.indd 206 www.ketabpezeshki.com 07/11/11 11:38 AM CHAPTER 10 Intravenous Therapy 207 Constant Factors Quick Formula with Constant Factor Milliliters per hour (mL/hr / r) Constant fact f or = Drops r per minute ((gtt/min) The constant factor is derived from the drop factor (of the administration set) divided into the fixed time factor of 60 min. It can only be used with the time factor of 60 min. Because the drop factor of 60 has the same numerical value as 60 min, these numbers cancel themselves out. A constant factor of 1 can be used in the division to replace both of these numbers. Therefore, for this Quick Formula, you can use the constant factor (1) to replace 60 min and 60 gtt per mL. Because 60 remains constant for this Quick Formula, you can calculate constant factors for other drop factors by dividing by 60. For example, when working with a drop factor of 10, you can use the constant factor of 6 (60 ÷ 10); 15 would give a constant factor of 4 (60 ÷ 15), and 20 would give a constant factor of 3 (60 ÷ 20). EXAMPLE: A Administer 1,000 mL of RL over 10 hr. The drop factor is 15 drops per mL. Use the Quick Formula to Calculate mL per hr CALCULATE ML PER HR: Total o volume = Milliliters per hour T tal hours To r 1, 000 mL = 100 mL/hr 10 hr (021) 66485438 66485457 LWBK914-C10_p191-218.indd 207 www.ketabpezeshki.com 07/11/11 11:38 AM 208 UNIT 3 Dosage Calculations Use the Constant Factor to Calculate Drops per Minute mL/hr = gtt/min Constant fact f or 100 mL/hr = 25 gtt/min 4 ((60 ÷ 15) ANSWER: 25 gtt per min Intermittent Intravenous Administration Intravenous Piggyback Medications An intermittent intravenous infusion is an intravenous preparation (usually electrolytes or antibiotics) that is “piggybacked” (IVPB) or connected to an existing IV line. The IVPB solution, usually 50 mL to 100 mL, is administered over 30 min to 60 min or less. The tubing for the secondary set will be shorter than the primary set and will have a drop factor of 60. It should be hung higher than the existing IV to allow the force of gravity to override the infusion of the primary IV. Remember: The greater the height, the greater is the pressure, and the faster is the rate of infusion! See Figure 10.3. If a piggyback medication is to be given at the same time as the primary infusion, the bag/bottle is hung at the same height and the setup is referred to as a tandem setup. Smaller quantities of solution (100 mL to 150 mL) and medications can be given via a burette chamber. These volume-controlled sets (Buretrol, Soluset, and Volutrol) are frequently used for pediatric doses (see Chapter 14). (021) 66485438 66485457 LWBK914-C10_p191-218.indd 208 www.ketabpezeshki.com 07/11/11 11:38 AM CHAPTER 10 Intravenous Therapy 209 FIGURE 10.3 IV piggyback delivery system. (From Taylor, C., Lillis, C., and LeMone, P. [2001]. Fundamentals of nursing. The art and science of nursing care [4th ed.]. Philadelphia: Lippincott Williams & Wilkins.) Frequently, the IVPB medication has to be reconstituted from a powder form (the type and amount of diluent will be specified), although some come premixed. You calculate the drip rate for the IVPB using the same formula that you used for the primary IV. If you are using an infusion pump, use the secondary IV (021) 66485438 66485457 LWBK914-C10_p191-218.indd 209 www.ketabpezeshki.com 07/11/11 11:38 AM 210 UNIT 3 Dosage Calculations setting and a drop factor of 60. Program the pump for the rate in mL per hr. EXAMPLE: Thhe physician ordered 1 g of Ancef in 100 mL of NS to be infused over 30 min via IVPB. The drop factor is 20 drops per mL. The IV should be infused at x drops per minute. The Standard Formula Total volume Drop fact f or Time in minutes = Dro r ps p per minute 100 mL × 20 (gtt/mL g ) 100 20 = 30 min 30 2, 000 = = 66.6 gtt/min 30 ANSWER: 67 gtt per min Intravenous Push (IVP) Medications Intravenous push medications should normally be given over 1 min to 5 min. Institution guidelines and reference materials provide acceptable rates of delivery and dilution requirements. Because the medication will have rapid effects, the total volume should be divided by the total minutes and then further divided into 15-sec increments. Use a watch to verify the time of infusion. See Figure 10.4. (021) 66485438 66485457 LWBK914-C10_p191-218.indd 210 www.ketabpezeshki.com 07/11/11 11:38 AM CHAPTER 10 Intravenous Therapy 211 FIGURE 10.4 IV push medication. (From Taylor, C., Lillis, C., LeMone, P., and Lynn, P. [2008]. Fundamentals of nursing. The art and science of nursing care [6th ed.]. Philadelphia: Lippincott Williams & Wilkins.) EXAMPLE: Thhe physician ordered 30 mL, IV push, STAT. The literature recommends dilution with 10 mL of NS and injection over 5 min. Flush with 10 mL of NS. Determine the total volume to be infused. 30 mL + 10 mL of dilution = 40 mL Total volume Total minutes = Milliliters pe p r minute Use: 40 mL = 8 mL/min 5 min (021) 66485438 66485457 LWBK914-C10_p191-218.indd 211 www.ketabpezeshki.com 07/11/11 11:38 AM 212 UNIT 3 Dosage Calculations Calculate mL to be given over 15 sec Total volume 4 (60 ÷ 15 sec) Milliliters ove v r 15 sec Use: 8 mL = 2 mL every 15 sec 4 ANSWER: 2 mL given every 15 sec Flush with 10 mL of NS (021) 66485438 66485457 LWBK914-C10_p191-218.indd 212 www.ketabpezeshki.com 07/11/11 11:38 AM You should give ________ drops per min. The drop factor is 20 drops per mL. (021) 66485438 66485457 LWBK914-C10_p191-218. You should give ________ mL per hr. The drop factor is 60 drops per mL.com 07/11/11 11:38 AM . 5. the hourly amount would be <100 mL? _______ Yes or No? 2. You are to give 600 mL of solution over 12 hr. You should give ________ drops per min. 3.45% NS to infuse over 6 hours. 4. Administer 500 mL of solution over 24 hr. You are to give 1. You should give ________ mL per hr. Administer 800 mL of NS over 10 hr. You should give ________ drops per min.indd 213 www.CHAPTER 10 Intravenous Therapy 213 PRACTICE PROBLEMS 1.000 mL is to be infused over 12 hr. You should give ________ drops per min. Critical Thinking Check Does it seem logical that if 1. 6.ketabpezeshki.000 mL of RL to infuse over 12 hr. The drop factor is 20 drops per mL. The drop factor is 15 drops per mL. The physician prescribed 1. You are to give 500 mL of NS over 4 hr.000 mL of 0. The drop factor is 15. (021) 66485438 66485457 LWBK914-C10_p191-218. You should set the flow rate at ________ drops per min. The drop factor is 10. The drop factor is 20. The physician prescribed an IV of 250 mL of NS to be run at 50 mL per hr. 10. The physician prescribed an IV of 500 mL of Ringer’s lactate at 75 mL per hr.com 07/11/11 11:38 AM . The drop factor is 15 gtt per mL. The physician prescribed an IV of 1. The physician prescribed an IV of 100 mL of D5W to run at 100 mL per hr. You should run the IV at ________ drops per min. 11.500 mL of Ringer’s lactate solution to infuse over 20 hr. The drop factor is 15 drops per mL.indd 214 www. 9. Give 50 mg of an antibiotic in 100 mL of D5W over 30 min.ketabpezeshki. You should give ________ drops per min. You should administer ________ drops per min. You should piggyback this medication into the main IV and give at ________ drops per min.214 UNIT 3 Dosage Calculations Critical Thinking Check Should you expect the rate of the infusion to be faster or slower if the drop factor was 15 gtt per mL instead of 20 gtt per mL? _______ Faster or slower? 7. 8. The drop factor is 60 drops per min. does it seem logical that the gtt per min should always equal the mL per hr? _______ Yes or No? 14.CHAPTER 10 Intravenous Therapy 215 12.22% NS to infuse over 10 hr. Critical Thinking Check If the drop factor of 60 is equal to the number of minutes in an hour (60). You should give ________ drops per min. (021) 66485438 66485457 LWBK914-C10_p191-218. The nurse should give ________ mL per hr and ________ drops per min. Administer 1 g of an antibiotic in 100 mL of D5W to run over 30 min.indd 215 www.ketabpezeshki. The nurse should give ________ drops per min. The physician prescribed an IV of 250 mL of D5 0.com 07/11/11 11:38 AM . Administer 1 g of an antibiotic in 50 mL of D5W over 30 min. The drop factor is 20 drops per mL. The drop factor is 10 gtt per mL. 13. 45% NS to run over 8 hr. The drop factor is 20 drops per mL.000 mL of D5 0. The flow rate should be ______ drops per min.End of Chapter Review Complete the following IV calculations: 1. 2. To deliver 1.9% NS over 8 hr. The nurse should give ______ mL per hr.ketabpezeshki.000 mL of 0. the nurse should set the flow rate to deliver ______ mL per hr. 3. A patient is to receive 500 mL of 0.45% NS over 4 hr. 4. 7. 6. the nurse should set the flow rate to deliver ______ mL per hr. the nurse should administer ______ mL per hr.indd 216 www. Administer 1. 5. To deliver 500 mL of D5W over a 6-hr period. You should give ______ mL per hr.com 07/11/11 11:38 AM . To infuse 500 mL of solution over 8 hr. you should give ______ mL per hr.000 mL over 10 hr. 216 (021) 66485438 66485457 LWBK914-C10_p191-218. The drop factor is 10 drops per mL. Administer 1. To deliver 250 mL of NS over a 5-hr period. The drop factor is 10. you should give ______ mL per hr. 14. Administer 1. 15. you should give ______ drops per min. The flow rate should be ______ drops per min. The drop factor is 15 drops per mL.CHAPTER 10 Intravenous Therapy 217 8. Use the Quick Formula with the constant factor. Ringer’s lactate.0 L of Ringer’s lactate over 6 hr. The physician prescribed 250 mL of D5W at 20 mL per hr. The total infusion time should be ______ hr. (021) 66485438 66485457 LWBK914-C10_p191-218. 500 mL. Use the Quick Formula with the constant factor.indd 217 www. The total infusion time should be ______ hr. 12. 9.000 mL of D5W 0. The flow rate should be ______ drops per min. The physician prescribed 1. You should give ______ drops per min.000 mL of RL at 50 mL per hr. 13. You should set the rate at ______ drops per min. 10. With a drop factor of 15 drops per mL. The microdrip provides 60 drops per mL. You are to give 500 mL of NS at 40 mL per hr.000 mL of D5W to infuse over 24 hr. The drop factor is 10 drops per mL. is to infuse at 50 mL per hr. Use the Quick Formula and the constant factor. To administer 1.com 07/11/11 11:38 AM . 11.9% NS to infuse at 75 mL per hr.ketabpezeshki. The physician prescribed 1. Administer 500 mL of D5W over a 12-hr period as KVO. The total infusion time should be ______ hr. The physician prescribed 500 mL of a 10% Intralipid solution to infuse over 4 hr.ketabpezeshki. The microdrip provides 60 drops per mL. You should give ______ drops per min. The drop factor is 60 drops per mL. 18. The nurse should run the IV at ______ drops per min.000 units of heparin over 24 hr. Using a pump. the nurse should set the rate at ______ mL per hr. The nurse should give ______ drops per min. 17. A patient is to receive 350 mg of an antibiotic in 150 mL of D5W over a 1-hr period of time. (021) 66485438 66485457 LWBK914-C10_p191-218. 19. A patient is to receive 1.com 07/11/11 11:38 AM .lww. Additional practice problems to enhance learning and facilitate chapter comprehension can be found on http://thePoint. 20.indd 218 www. Administer 100 mL of an antibiotic solution via an infusion pump over 60 min.218 UNIT 3 Dosage Calculations 16. The physician prescribed 100 mL of albumin to be absorbed over 2 hr.com/Boyer8e. The drop factor is 15 drops per mL.000 mL of NS with 20. The drop factor is 15 drops per mL. The nurse should give ______ drops per min. the dosage is based on the patient’s weight in kilograms. • Calculate critical care dosages.CHAPTER 11 Intravenous Therapies CRITICAL CARE APPLICATIONS LEARNING OBJECTIVES After completing this chapter. I n critical care situations small amounts of potent medications are ordered intravenously and must be carefully monitored.g. Some medications are ordered in units to be given over a specified time (e. heparin and insulin). • Titrate IV fluids. Some very potent medications 219 (021) 66485438 66485457 LWBK914-C11_p219-237. Other medications are ordered by amount of drug. per hour and per minute.com 07/11/11 11:39 AM .indd 219 www. Frequently..ketabpezeshki. you should be able to: • Calculate flow rate when critical care dosage is known. milligrams per hour (mg per hr). milligrams per minute (mg per min).indd 220 www. Intravenous infusions with critical care drugs must be administered with an electronic infusion pump or volume-controlled device.com 07/11/11 11:39 AM .ketabpezeshki. The nurse must be able to calculate both the desired dosage and mL per hr for the IV infusion. Refer to Appendix J for a review of nursing considerations for critical care drug administration. micrograms per minute (mcg per min). milligrams per kilogram per minute (mg/kg/min). or milliequivalents per minute (mEq per min) • grams per hour (g per hr). or milliequivalents per kilogram per minute (mEq/ kg/min). blood pressure. vasopressors. Critical care medications can be prescribed accordingly: • grams per minute (g per min). micrograms per hour (mcg per hr). Remember: You must always know the safe dosage dilution and rate of the medications you are administering before you begin the infusion.220 UNIT 3 Dosage Calculations (antiarrhythmics. or milliequivalents per hour (mEq per hr) • grams per kilogram per minute (g/kg/min). (021) 66485438 66485457 LWBK914-C11_p219-237. then a microdrip set at 60 drops per mL is necessary. or other parameters. Heparin and insulin infusions will be covered in their respective chapters. Refer to institutional guidelines or drug references when necessary. only a small sampling of critical care problems can be provided here. Please note: Due to the size of this book. and vasodilators) may be titrated to the patient’s heart rate. This chapter will focus on critical care problems. micrograms per kilogram per minute (mcg/kg/min). If these are not available. if dosage is ordered per minute. The rate is more likely to be changed to a whole number when the dosage is titrated and then the dosage change is documented.com 07/11/11 11:39 AM . the Formula Method. you use one of the same three methods shown in Chapter 10. The electronic infusion pump should be set at ______ mL per hr. change dosage per minute to dosage per hour (multiply by 60 before or after you calculate mL per hr). (021) 66485438 66485457 LWBK914-C11_p219-237. 500 mg in 250 mL D5W.CHAPTER 11 Intravenous Therapies 221 Additional practice problems to enhance learning and facilitate chapter comprehension can be found on http://thePoint. Use Ratio and Proportion.com/Boyer8e. Calculate Flow Rate (mL per hr) When Dosage Is Known.indd 221 www. Note: When calculating critical care infusions. do not round up to the whole number if the pump can be set in tenths. or dimensional analysis. and calculate mL per hr using ratio and proportion. the Formula Method. at 5 mcg/kg/min for a patient weighing 152 lb. calculate dosage per kilogram per minute or per kilogram per hour if the drug is ordered by weight.lww. EXAMPLE #1: G Give a critical care medication.ketabpezeshki. or Dimensional Analysis To calculate milliliters per hour. R U L E To calculate flow rate (mL per hr) when the dosage is known: Convert to like units. 000x 0 = 86. 000 mcg 86.000x 0 = 345 mcg/min × 250 mL 500. 250 = 0. 000 (carry a out twoo spaces to hundred r ths) x= (021) 66485438 66485457 LWBK914-C11_p219-237.2 mL/hr ANSWER: 10.000 mcg/mg = 500..com 07/11/11 11:39 AM .17 mL/min × 60 min/hr = 10. Change milligrams to micrograms (1 mg = 1.000 mcg): 500 mg × 1.250 86.2 mL per hr The Formula Method CALCULATE D ×Q = x ML/MIN USING H FORMULA: 345 mcg/min × 250 mL 500. 000 (carry a out twoo spaces to hundred r ths) x= CALCULATE ML/HR: 0.ketabpezeshki.222 UNIT 3 Dosage Calculations CONVERT TO LIKE UNITS: C Change pounds to kilograms (2.1725 mL/min 500.1 or 69 kg.2 lb/kg = 69.1725 mL/min 500.000 mcg : 250 mL 500.indd 222 www. 250 = 0.2 lb = 1 kg): 152 lb ÷ 2.000 mcg CALCULATE MCG/MIN: 5 mcg/kg/min × 69 kg = 345 mcg/min Ratio and Proportion 345 mcg/min : x mL = 500. 00 0000 1. 000 mc mcgg 60 min 1 kgg 152 lb × × × 1 hr 2.4 mL per hr EXAMPLE #2: Th he physician ordered 400 mcg of Precedex in 100 mL of NS to infuse at 0. you will need to use three conversion factors: 1 mg = 1.com 07/11/11 11:39 AM . 000 × 1 (h ) 2.4 mL/hr or 10 mL/hr 11 = ANSWER: 10.2 114 1111. CONVERT TO LIKE UNITS: Convert pounds to kilograms 132 lb ÷ 2.100.17 mL/min × 60 min/hr = 10.2 mL/hr ANSWER: 10. 000 11 114 = = 10.indd 223 www.2 lb.3 mcg/kg/hr for a person who weighs 132 lb. 5 mc mcgg 250 (mL) 1 mg × × kg/min kg /min 500 mg 1.000 mcg.ketabpezeshki.2 lb = 5 × 250 (mL) × 1 60 1 × 152 500 × 1. 400.CHAPTER 11 CALCULATE ML/HR: Intravenous Therapies 223 0.2 lb/kg = 60 kg CALCULATE MCG/HR: 0.2 mL per hr Dimensional Analysis To set up this equation. 60 min = 1 hr.3 mcg/kg/hr × 60 kg = 18 mcg/hr (021) 66485438 66485457 LWBK914-C11_p219-237. and 1 kg = 2. 3 g 100 (mL) = kg /hr 400 mc mcgg 1 kg = = 132 lb 2.800 x= 1. you will need one conversion factor: 1 kg = 2.5 mL per hr (021) 66485438 66485457 LWBK914-C11_p219-237.5 mL per hr The Formula Method D ×Q = x H 18 mcg/hr / ×100 100 400 mcg 4.2 lb 0.ketabpezeshki.5 mL/hr ANSWER: 4.2 3.5 mL per hr Dimensional Analysis To set up this equation. 960 = = 4 5 mL/hr 880 ANSWER: 4. 800 = 4 5 mL/hr / 400 ANSWER: 4.224 UNIT 3 Dosage Calculations Ratio and Proportion 18 mcg/hr : x mL = 400 mcg : 100 mL 400x 0 = 18 mcg/hr × 100 mL 400x 0 = 1.indd 224 www.3 100 (mL) × 1 132 400 × 2. 0.com 07/11/11 11:39 AM .2 lb. ketabpezeshki. How many milliliters per hour should the patient receive? Ratio and Proportion 900 mg : 500 mL = 0.indd 225 www.278 mL/min (0.28 mL/min × 60 min/hr = 16.28) mL/mi L n x= CALCULATE ML/HR: 0.CHAPTER 11 Intravenous Therapies 225 Thhe physician ordered 900 mg of amiodarone in 500 mL D5W to run at 0.5 mg/min : x mL 900x 0 = 250 (= 500 × 0.com 07/11/11 11:39 AM .8 mL per hr (021) 66485438 66485457 LWBK914-C11_p219-237.28 mL/min) CALCULATE ML/HR: 0.5 mg/ min.5) 25 250 25 = = 0 277 900 90 90 (0.28 mL/min × 60 min/hr = 16.8 mL/hr ANSWER: 16.8 mL/hr ANSWER: 16.8 mL per hr The Formula Method CALCULATE MG/MIN USING FORMULA: D ×Q = x H 0 5 mg/min × 500 mL 900 mg = 0. 7 mL per hr Calculate Dosage. How many mcg/kg/min should be infusing? (021) 66485438 66485457 LWBK914-C11_p219-237. mcg/kg/min). calculate dosage per kilogram per minute (g/kg/min.com 07/11/11 11:39 AM . 0 5 mg 500 mL 60 min × × minut mi nutee 900 mg 1 hr 150 0 5 × 500 ( ) 60 15. you will only need one conversion factor: 60 min = 1 hr.226 UNIT 3 Dosage Calculations Dimensional Analysis To set up this equation.ketabpezeshki. If the drug is ordered by weight. or dimensional analysis. the Formula Method. per Hour or per Minute.7 mL/hr / 9 = ANSWER: 16. 400 mg in 250 mL D5W. milligrams per minute. 000 = 900 × 1 (hr h) 900 9 150 = = 16. When Flow Rate Is Known R U L E To calculate dosage when the flow rate (mL per hr) is known: Convert to like units and calculate the dose (grams per minute. mg/kg/min. EXAMPLE #1: A medication. micrograms per minute) using ratio and proportion.indd 226 www. is to be infused at 20 mL/hr to maintain a systolic blood pressure (BP) of 100 mm Hg in a patient weighing 110 lb. 000625x = 0.2 lb/kg = 50 kg CALCULATE MCG/HR: 400.000 mcg/mg = 400.2 lb/kg = 50 kg CONVERT ML/ 20 mL/hr ÷ 60 min = 1.000 mcg/mg = 400.CHAPTER 11 Intravenous Therapies 227 Ratio and Proportion CONVERT TO LIKE UNITS: Change mg to mcg (400 mg × 1.000 (400.200 mL/min HR TO ML/MIN: x mcg/min × 250 mL D 400 .000 mcg) Convert pounds to kilograms 110 lb ÷ 2.33 x = 528 mL/min (021) 66485438 66485457 LWBK914-C11_p219-237.000.000 mcg : 250 mL = x : 20 mL/hr 250x 0 = 8. 000 mcg/hr 250 CHANGE MCG/ 32.000 mcg) Convert pounds to kilograms 110 lb ÷ 2. 000 mcg ×Q = x H = 0 33 mL/min USE 0.7 mcg/kg/min The Formula Method CONVERT TO LIKE UNITS: Change mg to mcg (400 mg × 1.com 07/11/11 11:39 AM .ketabpezeshki. 000.66 mcg/kg/ min ANSWER: 10.000 × 20) x= 8. 000 = 32.indd 227 www.000 mcg/hr ÷ 60 min = 533 mcg/min HR TO MCG/MIN: CHANGE TO MCG/KG/MIN: 533 mcg/min ÷ 50 kg = 10. indd 228 www. 000 0 (mcg) = = 1 hr 250 mL 1 mg 1 hr 2. 000 = 10. and 2. 600.ketabpezeshki.2 1 × 250 × 1 60 1×110 17.2 lb = 110 lb 6 min 1 kg 60 20 × 400 ×1.com 07/11/11 11:39 AM .228 UNIT 3 CHANGE TO MCG/KG/MIN: Dosage Calculations 528 mcg/min ÷ 50 kg = 10. ) mcg/kg/ / /min ANSWER: 10. 000 (mcg) ×11 2. 000 = 1. How many mcg/kg/hr or mcg/kg/ min should be infused? (021) 66485438 66485457 LWBK914-C11_p219-237.2 lb = 1 kg) to get mcg/kg/minute.66 (10. 60 min = 1 hr. • Use three conversion factors 20 mL 400 mg 1.56 mcg/kg/ min (10.000 mcg. you will use three conversion factors (1 mg = 1.7 mcg/kg/min EXAMPLE #2: A physician prescribes 4 mg of a drug in 250 mL D5W to be titrated to 4 mL per hr to control pain in a patient who weighs 115 lb.6) ANSWER: 10. 650.6 mcg/kg/min Dimensional Analysis To set up this equation. ketabpezeshki.0625x = 4 mL/hr x = 64 mcg/hr (021) 66485438 66485457 LWBK914-C11_p219-237.2 lb/kg = 52 kg) CALCULATE MCG/HR: D ×Q = x H x mcg/hr / × 250 mL = 4 mL/hr 4.com 07/11/11 11:39 AM .000 mcg : 250 mL = x : 4 mL/hr 250x 0 = 16. 000 = 64 mcg/hr / 250 64 mcg/hr ÷ 52 kg = 1.23 mcg/kg/min ÷ 60 min = 0. 000 mcg 0.02 mcg/ kg/min ANSWER: 1.indd 229 www.000 mcg/ mg = 4.000 mcg) Change 115 lb to kg (115 lb ÷ 2.000 × 4) x= CALCULATE DOSAGE IN MCG/KG/HR: CHANGE TO MCG/KG/MIN: 16.23 mcg/kg/hr 1.000 (4.CHAPTER 11 Intravenous Therapies 229 Use Ratio and Proportion CONVERT TO LIKE UNITS: Change mg to mcg (4 mg × 1.000 mcg/ mg = 4.02 mcg/kg/min The Formula Method CONVERT TO LIKE UNITS: Change mg to mcg (4 mg × 1.2 lb/kg = 52 kg) CALCULATE MCG/HR: 4.000 mcg) Change 115 lb to kg (115 lbs ÷ 2.23 mcg/kg/hr or 0. 60 min = 1 hr. 000 mcg = = hour 250 mL 1 mg 2. you will need to use two conversion factors (1 mg = 1.2 lb = = 115 lb 1 kg 4 × 1.2 lb) to get mcg/kg/min.com 07/11/11 11:39 AM . 000 (mcg) × 1 2.2 lb = = = 115 lb 60 min 1 kg (021) 66485438 66485457 LWBK914-C11_p219-237. 750 5 4 • Use three conversion factors 4 4 mg 1.23 mcg/kg/hr DOSAGE IN MCG/KG/HR: CHANGE TO MCG/KG/MIN: 1. and 1 kg = 2.22 mcg/kg/hr / 28.02 mcg/kg/ min ANSWER: 1.230 UNIT 3 CALCULATE Dosage Calculations 64 mcg ÷ 52 kg = 1.23 mcg/kg/hr or 0. 000 mcg = = hour 250 mL 1 mg 1 hr 2.02 mcg/kg/min Dimensional Analysis To set up this equation.2 lb) to get mcg/kg/hr and three conversion factors (1 mg = 1. • Use two conversion factors 4 4 mg 1.000 mcg and 1 kg = 2. 200 = = 1.2 1 × 250 × 1 × 115 35.indd 230 www.000 mcg.23 mcg/kg/hr ÷ 60 min = 0.ketabpezeshki. An infusion pump should always be used. 000 ANSWER: 1.com 07/11/11 11:39 AM . the lowest dose of medication is given first. NeoSynephrine).. 725. so you will need to calculate the infusion in mL per hr.22 mcg/kg/hr or 0. (021) 66485438 66485457 LWBK914-C11_p219-237. The solution being titrated contains 25 mg of medication in 500 mL D5W. R U L E When solving a solution problem involving titration: • Convert to like units. The nurse should set the pump to x mL per hr.2 250 × 1 60 1 × 115 35. and then the dosage is increased or decreased to achieve the desired result.02 mcg/kg/min Titrate IV Fluids When a medication is titrated (e.indd 231 www. • Convert the upper and lower dose ranges into mL/min.CHAPTER 11 Intravenous Therapies 231 4 4 × 1. The nurse needs to determine the setting for the infusion pump. 000 (mcg) × 1 2.g. Sometimes a bolus dose is initially given. • Convert mL per min into mL per hr. • Calculate the concentration in mcg per mL.ketabpezeshki. EXAMPLE: A critical care medication was ordered to be titrated (2 to 4 mcg per min) to maintain a systolic blood pressure below 130 mm Hg. dopamine. 200 = = 0 02 mcg/kg/ / /hr 1. 8 mL/hr ANSWER: The nurse should titrate the dosage range of 2 to 4 mcg per min by setting the pump to infuse at a flow rate of 2.000x 0 = 1.000 (= 2 × 500) UPPER AND LOWER DOSE RANGES INTO ML/MIN: x= 1.5 x = 0.indd 232 www.8 mL per hr.000x 0 = 2.232 UNIT 3 Dosage Calculations CONVERT TO LIKE UNITS: 25 mg = 25.ketabpezeshki.000 mcg : 500 mL = 2 mcg/min : x 25.4 mL/hr Upper dosage range: 0.4 to 4.000 mcg : 500 mL = 4 mcg : x 25. 000 1 = = 0 04 25.000 (= 4 × 500) x= 2.04 × 60 min = MIN TO ML/HR: 2. (021) 66485438 66485457 LWBK914-C11_p219-237.000 mcg (1 mg = 1. 000 2 1 = = = 0 08 25.08 mL/min = upper dosage range CONVERT ML/ Lower dosage range: 0.com 07/11/11 11:39 AM . 000 25 12.04 mL/min = lower dosage range 25.000 mcg) CONVERT THE The solution concentration is 50 mcg/mL 25.08 × 60 min = 4. 000 25 x = 0. 3.End of Chapter Review Complete the following problems: The physician prescribes 50 mg of a drug in 250 mL D5W to start at 10 mcg per min to relieve chest pain. 233 (021) 66485438 66485457 LWBK914-C11_p219-237. Critical Thinking Check If the prescribed dosage is doubled to 20 mcg per min. You should set the infusion pump at _____ mL per hr. would you expect the infusion pump setting to double (set at 6 mL per hr)? _______ Yes or No? 2. You should set the infusion pump at _____ mL per hr.ketabpezeshki. The nurse increased a lidocaine infusion of 2 g in 250 mL D5W to 30 mL per hr to control the patient’s dysrhythmia.com 07/11/11 11:39 AM .indd 233 www. You should document that the patient is now receiving _____ mg per min. The physician prescribes dopamine 400 mg in 250 mL D5W to start at 5 mcg/kg/min for a patient weighing 178 lb. You should document that the patient is receiving _____ mcg/kg/min. You should set the infusion pump at (021) 66485438 66485457 LWBK914-C11_p219-237. The label directs you to remove 90 mL from a 250-mL NS bag and add 200 mg of the medication. The concentration of medication should be _____ mg per mL (remember to include the volume of the of the drug in the calculation of the total volume). The medication vial has 5 mg per mL. You should set the infusion pump at _____ mL per hr. The physician prescribes lorazepam (Ativan) 250 mg in 250 mL to run at 3 mg per hr. Decrease.ketabpezeshki. The physician prescribes a continuous infusion of a drug to control hypertension.234 UNIT 3 Dosage Calculations Critical Thinking Check If the physician prescribed 800 mg of dopamine in 250 mL at 5 mcg/kg/min. A 75-kg patient on a mechanical ventilator is sedated with propofol (Diprivan) 1. 7. You should add _____ mL of procainamide to 100 mL NS.com 07/11/11 11:39 AM . In order to administer 1 mg per min. would you expect the mL per hr to _______ Increase. You should add _____ mL of the drug to the IV bag. 5. 6. The physician prescribes a loading dose of procainamide 500 mg in 100 mL NS over 30 min. or Remain the Same? 4. you should set the infusion pump at _____ mL per hr.indd 234 www. The label reads procainamide 500 mg per mL.000 mg in 100 mL at 10 mL per hr. A patient is to receive a diltiazem (Cardizem) bolus of 10 mg followed by a continuous infusion of Cardizem at 10 mg per hr. (021) 66485438 66485457 LWBK914-C11_p219-237. You should add _____ mL of Cardizem to the IV bag. The Cardizem vials contain 5 mg per mL. You should set the infusion pump at _____ mL per hr.CHAPTER 11 Intravenous Therapies 235 _____ mL per hr to deliver this bolus. The physician prescribes phenylephrine (NeoSynephrine) 100 mg in 250 mL D5W continuous infusion to run at 50 mcg per min. You should document that the patient is receiving _____ mcg/kg/min. you should set the infusion pump at _____ mL per hr to deliver 10 mg per hr.ketabpezeshki. Keeping in mind the new total volume in the IV bag.indd 235 www. Dopamine 800 mg in 250 mL D5W is infusing at 12 mL per hr in a patient weighing 195 lb. The loading dose is to be followed with a continuous infusion of procainamide 2 g in 250 mL D5W to run at 2 mg per min. You should set the infusion pump at _____ mL per hr. To administer the bolus you should give _____ mL over 2 min. would you expect the mcg/kg/min to _______ Increase or Decrease? 10. Critical Thinking Check If the flow rate were to increase to 18 mL per hr. 8. 9. To mix the continuous infusion you should inject 125 mg in a 100-mL bag of NS.com 07/11/11 11:39 AM . Tirofiban (Aggrastat) 12. with a concentration of 50 mg in 250 mL. Give 400 mg of dopamine in 250 mL of D5NS to infuse at 300 mcg per min.5 mg in 250 mL is prescribed to be infused at a rate of 0.ketabpezeshki. Nipride 50 mg is added to a 250-mL solution of D5W. the nurse should add _____ mL of Nitrostat to 250 mL of D5W and set the infusion pump flow rate at _____ mL per hr to deliver 20 mcg per min.1 mcg/kg/min in a patient weighing 82 kg. 11. IV. A hypertensive patient weighs 165 lb. IV. 13. _____ mcg per mL.indd 236 www. Using an infusion pump. A patient is to receive nitroglycerine (Nitrostat) 20 mcg per min. 14. the nurse should set the flow rate at _____ mL per hr. Nitrostat is available in a 10-mL vial labeled 5 mg per mL. To prepare a 200-mcg per mL solution. (021) 66485438 66485457 LWBK914-C11_p219-237. This solution should contain a concentration of Nipride. the rate is increased to 12 mL per hr.UNIT 3 236 Dosage Calculations To maintain the systolic BP above 90 mm Hg. Calculate flow rate in mL per hr. You document that the patient is now receiving _____ mcg per min. 12.com 07/11/11 11:39 AM . You should give _____ mL per hr. You should set the pump at _____ mL per hr. His physician prescribed nitroprusside (Nipride) 3 mcg/kg/ min. should you expect the mL per hr to _______ Increase or Decrease? If the quantity of solution increased to 500 mL of D5NS. A patient is started on a furosemide (Lasix) infusion to promote diuresis. Additional practice problems to enhance learning and facilitate chapter comprehension can be found on http://thePoint. Using an infusion pump. 16. You should document that the patient is receiving _____ mcg per min. you should set the pump at _____ mL per hr.lww. 17.CHAPTER 11 Intravenous Therapies 237 Critical Thinking Check If the infusion increased to 500 mcg per min. you should set the rate at _____ mL per hr. Octreotide (Sandostatin) 1.250 mcg in 250 mL is prescribed at 50 mcg per hr. You should set the pump at _____ mL per hr.indd 237 www. 18. should the mL per hr _______ Increase or Decrease? 15. at the same infusion of 300 mcg per min.000 mg in 200 mL is prescribed at 1 mg per min.000 mg in 250 mL NS at 10 mcg/kg/min to maintain a systolic BP of 90 mm Hg. In a patient weighing 95 kg.com 07/11/11 11:39 AM .ketabpezeshki.com/Boyer8e. (021) 66485438 66485457 LWBK914-C11_p219-237. Lasix 2. A patient is started on norepinephrine 4 mg in 250 mL D5W at 15 mL per hr. A patient is to receive dobutamine 1. • Describe the steps necessary to mix two types of insulin in one syringe.ketabpezeshki. • Compare the four different types of insulin preparations (rapid acting. and long acting) according to onset.com 07/11/11 11:40 AM . and duration. • Distinguish between a standard 1-mL (100-unit) syringe and a 0. • List the different types of insulin. peak. • Describe the steps necessary to prepare insulin for injection. you should be able to: • Explain the purpose of insulin. 238 (021) 66485438 66485457 LWBK914-C12_p238-257.5-mL (50-unit) syringe. • Describe how to use an insulin pump. short acting.CHAPTER 12 Insulin LEARNING OBJECTIVES After completing this chapter. • Distinguish among the various types of insulin devices. intermediate acting.indd 238 www. • Explain the concept of the sliding scale for insulin coverage. . Insulin enables the body to use glucose as a source of energy. Lente and Ultralente are being phased out. Insulins are identified by trade and generic names. When insulin is insufficient.2. The letter N refers to NPH (intermediate acting). (Courtesy of Eli Lilly Company. Levemir. glulisine. See Figures 12.ketabpezeshki. blood sugar rises and insulin injections may be necessary.1 Humulin R.1 and 12.” The capitalized trade name (e.CHAPTER 12 Insulin 239 Insulin Preparation Insulin is a natural hormone secreted by the islets of Langerhans in the pancreas to maintain blood sugar levels. IN.com 07/11/11 11:40 AM . The major insulin preparations in use today are the synthetic human insulins (Regular and NPH) and their analogs: aspart.g. and Lantus (long acting). Humulin) on the insulin drug label is followed by a letter that indicates the type of insulin. The insulin label identifies the source as “rDNA origin.indd 239 www. and R refers to Regular (short acting). FIGURE 12.) (021) 66485438 66485457 LWBK914-C12_p238-257. All analog insulins are clear and colorless. lispro (rapid acting). Indianapolis. This is a special order. IN.indd 240 www. intermediate-acting. Indianapolis.240 UNIT 3 Dosage Calculations FIGURE 12. (Courtesy of Eli Lilly Company. Insulin is classified according to its onset.1. short-acting. See Table 12. Intermediate-acting insulin (NPH) usually takes 1½ hr for onset and peaks in 12 hr. peak. The most common insulin concentration is U-100. and the vial of insulin should not be kept with the U-100 vials. and duration of action (rapid-acting.ketabpezeshki. Regular.) Types of Insulin Insulin is measured in units and supplied in 10-mL vials providing 100 units of insulin per milliliter. A U-100 syringe is used for U-100 and should only be used with extreme caution (special order) for U-500 insulin.com 07/11/11 11:40 AM . aspart.2 Humulin N. and long-acting insulin). and glulisine have been approved for IV use. Short-acting insulin (Regular) starts to work in 30 min to 60 min. Long-acting insulin (Lantus) can last for 24 hr and is used for once-daily dosing. Insulin is also available as U-500 (500 units per milliliter) for individuals with difficult-to-manage blood sugar levels. Rapidacting insulin (lispro) is used when an effect is needed in 5 min to 30 min. (021) 66485438 66485457 LWBK914-C12_p238-257. (021) 66485438 66485457 LWBK914-C12_p238-257. Onset. and Duration of Action Insulin Onset Peak Duration 10–15 min 1/2–1 1/2 hr 3 hr or less 5 min 1 hr 2–4 hr 10–20 min 1–3 hr 3–5 hr 1/2–1 hr 2–3 hr 5–8 hr 1/2 hr 2 1/2–5 hr 8 hr 1/2 hr 2 1/2–5 hr 8 hr 1–3 hr 2–8 hr 14–24 hr 1 1/2 hr 4–12 hr 24 hr 1 1/2 hr 4–12 hr 24 hr No 20–24 hr No Up to 24 hr Rapid-acting Apidra (glulisine)* Humalog (lispro) Novolog (aspart)* Short-acting Humulin R (Regular)* Novolin R (Regular) ReliOn R (Novolin R) Intermediate-acting Humulin N (NPH) Novolin N (NPH) ReliOn N (Novolin N) Long-acting Lantus (insulin 1 hr glargine) Levemir 1–2 hr (insulin detemir) *Approved for IV use.CHAPTER 12 Insulin 241 Table 12. Peak.com 07/11/11 11:40 AM .ketabpezeshki.1 Insulin Type.indd 241 www. This syringe is only used for insulin! The most common. which is always ordered and supplied in units. use only Humulin N (NPH).indd 242 www. the 30 units that you draw from the vial would contain 21 units of NPH (70% of 30) and 9 units of Regular (30% of 30). Therefore only a brief description of each will be provided. Examples of other preparations are: Humalog 75/25. Novolin N (NPH). Note that N insulin does not indicate NovoLog insulin or Novolin 70/30. is given with a special 1-mL syringe marked in units (100 units per milliliters). then the full drug name would appear on the order. The size of this handbook prevents a comprehensive review of all devices. Insulin Delivery Devices There are a variety of insulin delivery devices: syringes. Humulin 70/30. If Novolog or Novolin 70/30 were desired. if a physician orders 30 units of Novolin 70/30.242 UNIT 3 Dosage Calculations Insulin also comes in premixed combinations. Humalog 50/50.com 07/11/11 11:40 AM . single-scale 1-mL (U-100) syringe is calibrated every 2 units. Syringes Insulin. If a physician orders 25 units of N insulin. The ratio of the combined insulin always equals 100%—for example. A double-scale 1-mL (U-100) syringe (021) 66485438 66485457 LWBK914-C12_p238-257. Therefore. and Humulin 50/50.ketabpezeshki. with every 10th unit marked in large numbers on one side (Figure 12. Novolin 70/30 (70% NPH and 30% Regular). pens and pumps. or ReliOn N.3 A). NovoLog 70/30. and injection ports (Insulfon and the i-port). 5-mL (holds up to 50 units of U-100 insulin) or 0.ketabpezeshki. Every 5 units are marked in large numbers on the left side. The smaller 0. FIGURE 12. A 0.3 B). but the 1-mL self-capping U-100 (021) 66485438 66485457 LWBK914-C12_p238-257. This makes it easier to accurately measure odd and even unit increments.5-mL syringe makes it easier to read. Patients are encouraged to choose the smallest syringe size that will contain the dose of insulin to be administered. Shaded area indicates 35 units of Regular insulin in a 0.indd 243 www. Becton Dickinson) syringe is sized to hold no more than 50 units of U-100 insulin.3-mL (holds up to 30 units of U-100 insulin) syringe is recommended sometimes for home use.5-mL (Lo-Dose. reducing the syringe capacity to 0. Note that the insulin concentration is the same (100 units per milliliter).5-mL syringe.3 Two common types of insulin syringes.CHAPTER 12 Insulin 243 USE U-100 ONLY A: Standard U-100 insulin syringe with 2-unit calibration markings every 10 units. but the barrel of the syringe is thinner. USE U-100 ONLY B: A Lo-Dose U-50 insulin syringe with 1-unit calibration markings every 5 units. The enlarged scale of the 0.5 mL (50 units). Shaded area indicates 60 units of Regular insulin in a 1-mL syringe.com 07/11/11 11:40 AM . There are 1-unit calibration markings and large numbers every 5 units (Figure 12. and every 10 units are marked on the right side. has 2-unit calibrations. Hold the needle in the subcutaneous tissue to the count of 5 after administering the dose to ensure complete delivery. Pens and Pumps Disposable Pens Insulin is also available in prefilled.ketabpezeshki. Then dial-in the desired dose. The reservoir should always be checked to make sure that the desired dose is available.com 07/11/11 11:40 AM . Make sure to fully depress the button on the pen.indd 244 www. Multiple rates can be programmed. Most insulin pumps in use today are individually programmed to calculate (021) 66485438 66485457 LWBK914-C12_p238-257. Insulin Pumps Continuous subcutaneous insulin infusion pumps deliver a constant dose of rapid-acting insulin.244 UNIT 3 Dosage Calculations insulin syringes are preferred in medical facilities to reduce errors in dosing. via tubing and a plastic cannula or small needle inserted into the subcutaneous tissue. Watch for 1 or 2 drops of insulin to leave the pen needle to ensure proper pen function. In addition. at a preset (basal) rate of units per hour. disposable pens or cartridges for reusable pens. and depress the button while holding the pen with the pen needle pointed upright. The insulin is administered subcutaneously. A function check should be done prior to administering an insulin dose with a pen. using a darting technique. Pens contain an insulinfilled cartridge. a specific dose (bolus) of rapid-acting insulin is programmed as needed to “cover” a meal or to “correct” for high glucose. Dial-in 1 to 2 units. The pen needle is removed and discarded immediately after each use. 4 Insulin pump. i-port) (021) 66485438 66485457 LWBK914-C12_p238-257. Insulfon. Injection Ports. Spray Injectors.) “bolus” dosages based on the carbohydrate content of the meal and the current blood glucose level... and Lynn.ketabpezeshki.4. The person using an insulin pump should insert a new infusion set in a new location every 48 hr to 72 hr. Fundamentals of nursing. P. C. See Figure 12.indd 245 www. The art and science of nursing care [6th ed.]. Philadelphia: Lippincott Williams & Wilkins. LeMone. [2008].CHAPTER 12 Insulin 245 SE L AC T FIGURE 12.. Note that only short.or rapid-acting insulin is placed in the insulin pump reservoir! This insulin is drawn up from a conventional 10-mL vial of U-100 R or rapid analog insulin.com 07/11/11 11:40 AM . C. (From Taylor. Lillis. P. and the i-port The production of inhaled insulin has been suspended in the United States. Injection ports (Insulfon. The dosage and frequency of insulin depend on the blood sugar level and are ordered using a sliding scale.. (021) 66485438 66485457 LWBK914-C12_p238-257. A site rotation schedule is used to minimize the overuse of one area for subcutaneous injection.g. Insulin orders are written in units.. Humalog [lispro].g. the cannula is inserted subcutaneously with a 31-gauge insertion needle. Regular and rapid analog insulins (Novolog [aspart]. Apidra [glulisine]) are used. See Table 12. the route (subcutaneous or IV). Regular. Rather than tubing being connected to a constant insulin supply (pump).ketabpezeshki. the units. 1/2 hr before meals. and insulin may be injected through the diaphragm for up to 3 days.com 07/11/11 11:40 AM . The infusion ports are similar to insulin pump infusion sets. at bedtime). and U-100 (100 units per milliliter) strength is used almost exclusively. Sliding Scale Coverage Sometimes patients receive additional rapid insulin during the day to correct high blood sugar. Lantus). which is then removed. Insulin Administration Insulin is never ordered orally or intramuscularly. and the time (e.2.indd 246 www. Only one type of insulin may be injected per port to prevent “mixing” of insulins.246 UNIT 3 Dosage Calculations are available and are sometimes used to reduce the number of injections for young children or adults with needle phobia. Orders must include the type of insulin (e. The port is taped to the skin. Remember these tips: • Never shake the insulin vial! Always mix the suspended (cloudy) insulins by rolling between the palms of your hands. call MD Preparing Insulin for Injection To prepare insulin for injection.ketabpezeshki. • Choose an insulin syringe large enough to hold 60 units. You should choose the vial of insulin marked N (Humulin N. You would fill a 1-mL insulin syringe to the 60-unit line.indd 247 www. Check the vial label three times. Novolin N) 100 units per milliliter. For example. • Draw up the required dose by filling the syringe to the desired calibration.com 07/11/11 11:40 AM .CHAPTER 12 Insulin 247 Table 12. (021) 66485438 66485457 LWBK914-C12_p238-257. a patient is ordered 60 units of NPH insulin. Regular insulin may be mixed in a syringe with NPH. • Select the correct insulin vial.2 Sample Sliding Scale for Insulin Coverage Blood Sugar (mg/dL) Insulin Coverage ≤180 181–260 261–310 311–420 >421 None 3 units 6 units 8 units 10 units. noting the type of insulin and number of units ordered. follow these steps: • Read the medication order. You should choose a 1-mL U-100 insulin syringe. Remember. 2. usually Regular and NPH.ketabpezeshki. Always draw up Regular insulin first. Always draw up the NPH insulin last because chemically it has a protein substance in it that Regular insulin does not have.248 UNIT 3 Dosage Calculations • The insulin analogs must never be mixed in a syringe with another insulin. • Refer to Appendix E for information about a subcutaneous injection. Choose a 0. Levemir and Lantus should never be mixed in a syringe with another insulin! When you have to mix insulins. there are five important guidelines that you must remember: 1.indd 248 www.com 07/11/11 11:40 AM . 3. Note: Always inject air into the NPH vial first! (021) 66485438 66485457 LWBK914-C12_p238-257. use a 1-mL (100-unit) insulin syringe for larger combinations. Always add air into each vial equal to the amount of the required dose. Do not contaminate the contents of one vial with the contents of the other vial. Only R (shortacting) insulin or rapid-acting insulin analogs may be added to an IV. Drawing up the NPH insulin last helps prevent contamination of the Regular insulin. 5. Air prevents a vacuum from occurring. Mixing Two Types of Insulin in One Syringe Occasionally you will find it necessary to mix two types of insulin. 4.5-mL (50-unit) insulin syringe to measure smaller dosages. ketabpezeshki. Know the type of insulin ordered and the total number of units prescribed. Regular and NPH. (021) 66485438 66485457 LWBK914-C12_p238-257. • Wash your hands and obtain the correct vials of U-100 NPH and Regular insulin and the correct U-100 syringe. Remove the needle. NPH is cloudy in appearance.CHAPTER 12 EXAMPLE: Insulin 249 Thhe physician prescribed 20 units of NPH and 10 units of Regular. follow these steps and refer to the illustrations A through G.indd 249 www. • Cleanse the tops of both vials with an alcohol swab. Never shake the vial! • Inject air equal to the insulin dose of NPH (20 units) into the NPH insulin vial first (A). Regular is always clear and colorless in appearance. Be careful that the needle does not touch the solution because air should not be bubbled through the solution.com 07/11/11 11:40 AM . • Check the medication order. • Use the same syringe and inject air equal to the dose of Regular insulin (10 units) into the Regular insulin vial (B). Do not touch the insulin solution with the tip of the needle. To mix two types of insulin in one syringe for injection. Rotate the vial of NPH between the palms of your hands. • Remove the syringe from the vial of Regular insulin (D) and check for air bubbles. draw up additional medication for correct dosage.indd 250 www.ketabpezeshki. If necessary.Dosage Calculations 50 0 50 50 45 45 45 45 40 40 40 40 35 5 35 35 30 30 30 30 25 5 25 25 20 20 20 20 15 1 5 15 10 10 10 5 20 units of air 10 units of air NPH A 5 UNIT 3 250 Reg B • Invert the vial of Regular insulin and draw back the required dosage (C). (021) 66485438 66485457 LWBK914-C12_p238-257. Check the dosage (10 units).com 07/11/11 11:40 AM . Tap the syringe to remove any bubbles. which should be the addition of the two insulins (G).com 07/11/11 11:40 AM . There should be a total of 30 units in the syringe (F). and the medication must be drawn up again. being careful not to inject any Regular insulin into the NPH vial.CHAPTER 12 Insulin 251 Reg 10 units of Regular insulin 5 10 10 15 15 20 0 25 5 30 0 10 units of Regular insulin 5 10 10 15 15 20 0 25 5 30 0 35 5 35 5 40 0 40 0 45 5 45 5 50 0 50 0 C D • Put the syringe into the NPH vial (E). • Check the dosage.ketabpezeshki. • Invert the vial of NPH and withdraw the required dosage (20 units) while holding the syringe at eye level. Air bubbles at this point indicate an incorrect dose. (021) 66485438 66485457 LWBK914-C12_p238-257.indd 251 www. com 07/11/11 11:40 AM . EXAMPLE: The physician ordered 25 units of Regular insulin/hr.ketabpezeshki. The infusion pump should be set to x mL/hr. Available is 125 units of Regular insulin in 250 mL NS.UNIT 3 252 Dosage Calculations • Prepare to administer the correct dose. NPH 50 45 40 35 30 25 20 15 10 10 units of Regular insulin Withdraw 20 units of NPH. A total of 30 units 5 10 15 20 25 30 30 units (10 Regular plus 20 NPH) 5 10 15 20 25 30 35 35 40 40 45 45 50 50 5 NPH E F G Continuous Intravenous Insulin Infusion Administering insulin by continuous IV infusion requires using an infusion pump to guarantee accurate dosage and infusion rate. IV.indd 252 www. Consider the following. (021) 66485438 66485457 LWBK914-C12_p238-257. (021) 66485438 66485457 LWBK914-C12_p238-257.indd 253 www.ketabpezeshki.com 07/11/11 11:40 AM .CHAPTER 12 Insulin 253 The Formula Method D ×Q = x H 25 units × 250 mL 125 units 1 25 250 125 5 × 250 = 5 1 50 = 50 mL ANSWER: Set the pump to deliver 50 mL/hr. USE U-100 ONLY 254 (021) 66485438 66485457 LWBK914-C12_p238-257. 1. Indicate 82 units U-100 insulin.ketabpezeshki. Indicate 45 units U-100 insulin.indd 254 www.com 07/11/11 11:40 AM . USE U-100 ONLY 4. USE U-100 ONLY 2. Indicate 35 units U-100 insulin.End of Chapter Review Complete the following problems: Look at the following syringes and identify the correct dosage of insulin by using an arrow to mark your answer or shade in the areas. Indicate 60 units U-100 insulin. USE U-100 ONLY 3. com 07/11/11 11:40 AM . __________ units (021) 66485438 66485457 LWBK914-C12_p238-257. USE U-100 ONLY 6.CHAPTER 12 Insulin 255 5. Indicate 16 units Regular U-100 insulin combined with 40 units NPH U-100 insulin. USE U-100 ONLY Identify the insulin dosage indicated by the shaded area on the following syringes. 10 __________ units __________ units USE U-100 ONLY 10. 45 40 35 30 25 20 15 10 5 USE U-100 ONLY 50 45 40 35 30 25 20 15 5 9.indd 255 www. __________ units 8. Indicate 10 units Regular U-100 insulin combined with 16 units NPH U-100 insulin.ketabpezeshki. Unit Unit 90 100 50 80 70 60 50 40 30 10 20 USE U-100 ONLY 7. Critical Thinking Check Does it seem logical or not logical to use a U-100 syringe because the Regular insulin is U-100? ________ Logical or Not Logical? (021) 66485438 66485457 LWBK914-C12_p238-257. indicate the total insulin dosage in the first column and the appropriate syringe (0. The physician ordered 30 units of U-100 Regular insulin to be given before lunch. You should select a ______ syringe and draw up ______ units of Regular insulin.ketabpezeshki. 30 units NPH 15 units Regular ___________ ___________ 13. 18 units Regular 20 units NPH ___________ ___________ 15. 20 units NPH 10 units Regular ___________ ___________ 16. Total Dosage Syringe/mL 11.indd 256 www.5 mL or 1 mL) in the second column. 5 units Regular 16 units NPH ___________ ___________ 12. 28 units Regular 36 units NPH ___________ ___________ 14.com 07/11/11 11:40 AM .256 UNIT 3 Dosage Calculations For the combined doses of insulin. com 07/11/11 11:40 AM . You should give a combined dose of ______ units in a _____ syringe. Could the nurse have used a 0. Additional practice problems to enhance learning and facilitate chapter comprehension can be found on http://thePoint. Critical Thinking Check There were only 1-mL syringes available for the 50-unit dose.5-mL syringe if it were available? ________ Yes or No? 20. 19. The physician prescribed 15 units of Humulin R insulin to be given subcutaneously at 11:00 AM to cover a blood sugar reading of 325.com/Boyer8e.ketabpezeshki.indd 257 www. the nurse should draw up ______ units. Using a 1-mL (100 unit) insulin syringe.5-mL syringe and draw up ______ units.lww. the nurse should draw up a total of ______ units. (021) 66485438 66485457 LWBK914-C12_p238-257. The physician prescribed a combination of 22 units of NPH insulin and 12 units of Regular insulin. making certain to draw up the ______ insulin last. 18.CHAPTER 12 Insulin 257 17. You have been asked to give 15 units of Humulin R insulin and 24 units of Humulin N. The physician prescribed 50 units of Humulin N insulin to be given subcutaneously at 8:00 AM. The nurse should use a 0. Using a U-50 insulin syringe. ketabpezeshki. you should be able to: • • • • Explain the purpose of heparin. 258 (021) 66485438 66485457 LWBK914-C13_p258-279. Calculate heparin flow rate (mL/hr) when heparin is ordered in units/hr. • Calculate heparin flow rate (mL/hr) when heparin is ordered based on weight (units/kg/hr).CHAPTER 13 Heparin Preparation and Dosage Calculations SUBCUTANEOUS AND INTRAVENOUS LEARNING OBJECTIVES After completing this chapter. Calculate heparin dosage for subcutaneous injection.indd 258 www. • Calculate heparin dosage (units/hr) when heparin is ordered in mL/hr. Calculate heparin dosage for intravenous infusion.com 07/11/11 11:42 AM . . 000. 5. twice daily) and administered subcutaneously. When heparin is prescribed based on weight. The physician attempts to maintain a therapeutic anticoagulation level by titrating the dosage based on the laboratory results of the partial thromboplastin time (PTT). Central intravenous lines are flushed with 3 mL of a heparin lock solution (100 units per mL). a bolus. Heparin is available in various solution strengths of units per mL: 10.000. Heparin is available in single and multidose vials. units/kg/hr) or mL/hr.indd 259 www.e. 1. followed by a continuous heparin infusion prescribed in units/kg/hr and given via an infusion pump. It is prepared in prefilled syringes in different amounts. Heparin is ordered in USP units (units/hr.ketabpezeshki. 20.000. 100. (021) 66485438 66485457 LWBK914-C13_p258-279.000. or loading dose. H eparin is an anticoagulant that prevents the formation of a new clot and the extension of an existing clot. Heparin is most effective when ordered based on weight (kg). Heparin can be given subcutaneously or intravenously for intermittent (heparin lock) or continuous infusion using an electronic infusion pump.. 1 mg per kg. and 40.CHAPTER 13 Heparin Preparation 259 • Explain the intravenous heparin protocol. Lovenox is a commonly used lowmolecular-weight anticoagulant ordered by weight (i. 10. Calculate bolus dose and infusion rate using an intravenous heparin protocol. is ordered in units/kg.com 07/11/11 11:42 AM . Saline flush solution (10 units per mL or 100 units per mL) is used periodically to maintain catheter patency.000. 000 units to 40. determine that the prescribed dose is within normal limits and can safely be given based on the patient’s coagulation laboratory test results (PTT).) (021) 66485438 66485457 LWBK914-C13_p258-279.000 units per 24 hr. See Figure 13. (Courtesy of Eli Lilly Company. To safely prepare heparin. Indianapolis. IN.ketabpezeshki.1. first read the vial label carefully! Next. FIGURE 13. verify the route of administration and calculate the 24-hr dosage to estimate safety of drug administration.com 07/11/11 11:42 AM . Then.indd 260 www.260 UNIT 3 Dosage Calculations Subcutaneous heparin works in 20 min to 60 min. whereas IV heparin is immediate.1 Heparin sodium injection. The normal heparinizing adult dosage is 20. 000 units.000x 0 = 5. SELECT: Seelect heparin 10. Use a tuberculin or prepackaged syringe to administer.indd 261 www. CHECK: D Determine if the prescribed dose is within the normal heparinizing adult dosage for 24 hr.CHAPTER 13 Heparin Preparation 261 Heparin for Subcutaneous Injection R U L E To prepare heparin for subcutaneous injection: Determine that the dose is within the safe. EXAMPLE #1: G Give heparin 5. Use one of the three standard methods for dosage calculation. q6h.000 units : 1 mL = 5. equals 20. 5-mL vial.000 units per mL.000 units in 24 hr (5. 000 1 = = 0 5 mL 10.000 units × 4 doses).com 07/11/11 11:42 AM . 000 2 2 ANSWER: 0.000 1 x= 5. This is within the safe normal dosage.5 mL (021) 66485438 66485457 LWBK914-C13_p258-279. Ratio and Proportion 10. normal range and calculate the desired amount based on the available amount of the dose.ketabpezeshki.000 units subcutaneously every 6 hr. Heparin 5.000 units : x mL 10. 5 mL Dimensional Analysis 5. Heparin 3. 000 mL = 10.262 UNIT 3 Dosage Calculations The Formula Method D ×Q = x H 5.ketabpezeshki. 000 units 1 x= 5. 000 un units its 5. equals 6. 000 1 = = 0 5 mL 10.000 units.000 units 10.000 units of heparin to be administered subcutaneously every 12 hr.000 × 2) in 24 hours. 000 × 1 ( ) 5.5 mL EXAMPLE #2: A patient is prescribed 3. q12h.indd 262 www.000 units i 1 = = 0 5 mL 2 = ANSWER: 0.000 units (= 3. 000 units ×1 mL = x 10.com 07/11/11 11:42 AM .000 un units its × 1 ((mL) = 10. 000 2 2 ANSWER: 0. (021) 66485438 66485457 LWBK914-C13_p258-279. This is below the normal dosage and safe to give. CHECK: D Determine if the prescribed dose is within the normal heparinizing adult dosage for 24 hours. 000 units per mL.CHAPTER 13 SELECT: Heparin Preparation 263 Seelect heparin 5. Ratio and Proportion 5.000 units : x mL 5. 000 3 = = 0 6 mL 5. 000 units ×1 mL = x 5.6 mL (021) 66485438 66485457 LWBK914-C13_p258-279.com 07/11/11 11:42 AM . 10-mL vial.6 mL The Formula Method D ×Q = x H 3. 000 units = 3. 000 3 = = =06 5.000 3 x= 3. 000 5 5 ANSWER: 0.6 mL Dimensional Analysis 3. 000 5. 000 units × 1 (mL) 5. 000 units 3 3. 000 5 5 ANSWER: 0. 000 5 5 ANSWER: 0.indd 263 www. 000 3 = = 0 6 mL 5.000 units : 1 mL = 3.000x 0 = 3.ketabpezeshki. 000 × i 1 mL 5. 000 ×1 (mL) 3. 000 un units its 3 = 3. 000 U/mL. EXAMPLE: The physician ordered 25. Heparin is available in a vial marked 5.ketabpezeshki. (021) 66485438 66485457 LWBK914-C13_p258-279.000 units of heparin in 0. Use one of the three standard methods of calculation. How many mL of heparin should the nurse add to the IV fluid? The Formula Method D ×Q = x H 25.com 07/11/11 11:42 AM . 000 25 5 = = = 5 mL 5. The Formula Method will be used here as an example. R U L E To add heparin to an IV: Calculate the desired quantity based on the available concentration.000 units × 1 mL = x 5.264 UNIT 3 Dosage Calculations Heparin for Intravenous Infusion Special calculations are required when administering IV heparin.5 NS.indd 264 www. 000 5 1 ANSWER: Add 5 mL of heparin to IV solution.000 units 25. 000 25 = = 25 mL/hr 20. You have available 500 mL of D5W with 20.000 units : x mL 20.ketabpezeshki. EXAMPLE #1: Th he physician ordered 1.000) 25 x= 500.indd 265 www.000 units of heparin added.000 (500 × 1.000 units per hr of heparin. 000 units (021) 66485438 66485457 LWBK914-C13_p258-279.com 07/11/11 11:42 AM . 000 1 1 ANSWER: 25 mL per hr The Formula Method D ×Q = x H 1.000 units : 500 mL = 1. Use an infusion pump to administer. Calculate the flow rate in mL per hr.000x 0 = 500. 000 units × 500 = x 20. Ratio and Proportion 20.CHAPTER 13 Heparin Preparation 265 Calculate Heparin Flow Rate (mL/hr) When Units of Heparin per Hour Are Ordered R U L E To calculate flow rate (mL per hr) when heparin is ordered in units per hour: Calculate the desired hourly amount based on the available amount. Use one of the three standard methods of calculation. 000 units 1.indd 266 www. 000 1 1 ANSWER: 24 mL per hr (021) 66485438 66485457 LWBK914-C13_p258-279. 000 un units its 500 ( mL ) × hr 20. 000 = 25 mL/hr 20. Ratio and Proportion 25. An infusion pump will be used. 000 units × 500 20 20. Calculate the flow rate in mL per hr.000 (1.000 × 600) 24 x= 600.000x 0 = 600.000 mL of D5W with 25.000 mL = 600 units : x mL 25.000 units of heparin added.000 un unit itss 1. 000 25 = 500. 000 units 1 500 25 × 500 = = = 25 mL/hr 20 20 1 ANSWER: 25 mL per hr Dimensional Analysis 1. 000 × 500 (mL) = 20. 000 1 ANSWER: 25 mL per hr EXAMPLE #2: Th he physician ordered 600 units per hr of heparin. 000 24 = = 24 mL/hr 25.ketabpezeshki.000 units : 1. 000 units 500 mL × hr 20.com 07/11/11 11:42 AM . You have available 1.266 UNIT 3 Dosage Calculations 1 1. 000 25. 000 000 1 24 = = 24 mL/h m r 1 ANSWER: 24 mL per hr Dimensional Analysis 600 units 1.ketabpezeshki.com 07/11/11 11:42 AM . 000 mL = x 25. 000 mL = 25. 000 25. 000 (mL) × hr 25. 000 = 25. 00 0000 ×1. 000 1 24 = = 24 mL/hr 1 = ANSWER: 24 mL per hr (021) 66485438 66485457 LWBK914-C13_p258-279. 000 units 600 units units 1. 000 uni units ts 24 600 ×1. 000 units 24 600 600.indd 267 www.CHAPTER 13 Heparin Preparation 267 The Formula Method D ×Q = x H = 600 units × 1. 000 (mL) 600. 000 mL × hr 25. 000) x = 900 units/hr ANSWER: 900 units per hr (021) 66485438 66485457 LWBK914-C13_p258-279.000x 0 = 900.000x 0 = 900.000 (30.000 (30 × 30.com 07/11/11 11:42 AM .000 units Give of heparin to infuse at 30 mL per hr. 000 1.ketabpezeshki.000 mL of D5W with 30. 000 mL = 30 mL/hr 30.000 mL = x units : 30 mL 1.000 units : 1.indd 268 www.268 UNIT 3 Dosage Calculations Calculate Heparin Dosage (units per hr) When Heparin Is Ordered in Milliliters per Hour R U L E To calculate units per hour when heparin is ordered in mL per hr: Calculate the desired hourly amount based on the available amount. Calculate the hourly dosage of heparin.000 × 30) 900 x= 900. 000 1 = 900 x = 900 units/hr ANSWER: 900 units per hr The Formula Method D ×Q = x H x units/h s r ×1. 000 1. Use one of the three standard methods of dosage calculation. EXAMPLE: G 1. Ratio and Proportion 30. ketabpezeshki. 000 1 1 = 900 units ts/hr = ANSWER: 900 units per hr Heparin Administration Based on Weight Calculate Heparin Flow Rate (mL/hr) When Heparin Is Ordered Based on Weight (units/ kg/hr) R U L E To calculate the flow rate (mL/hr) when heparin is ordered in units/kg/hr: Convert to like units (lb to kg). 000 mL 30 × 300. and calculate mL/hr using one of the three standard methods to calculate dosages.com 07/11/11 11:42 AM . calculate units/hr.indd 269 www. 000 900 = 1. 00 units × hr 1. 000 ( i ) = 1. 000 ( units) × hr 1. 000 900 900.CHAPTER 13 Heparin Preparation 269 Dimensional Analysis 30 mL 300. The Formula Method is used here as an example. 000 mL 30 mL 300. (021) 66485438 66485457 LWBK914-C13_p258-279. 270 UNIT 3 Dosage Calculations EXAMPLE: A physician orders heparin 12.indd 270 www.75 or 18 mL/hr ANSWER: Set the infusion pump at 18 mL per hr Calculate Heparin Dosage by Weight (units/ kg/hr) When Heparin Is Ordered by Flow Rate (mL/hr) R U L E To calculate units/kg/hr when the flow rate (mL/hr) is known: Convert to like units (lb to kg) and calculate the units/hr.4 kg Round to the nearest tenth (56 kg) R CALCULATE UNITS/HR: 166 units/kg/hr × 56 kg = 896 units/hr USE THE FORMULA METHOD: D ×Q H TO CALCULATE ML/HR: 8896 units/h s r × 250 mL = x 1 12.ketabpezeshki.500 units in 250 mL D5W to run at 16 units/kg/hr for a patient weighing 124 lb. CONVERT LB TO KG: 1224 lb ÷ 2.500 units mL/hr / SOLVE FOR X : x = 17. (021) 66485438 66485457 LWBK914-C13_p258-279.2 lb/kg = 56. Ratio and Proportion will be used here.com 07/11/11 11:42 AM . Use one of the three standard methods of calculation. The nurse should set the infusion pump at ____ mL per hr. The initial dose of heparin (bolus dose) is ordered in units per kg and is followed with a continuous intravenous infusion.1.2 lb/kg = 86 kg CALCULATE UNITS/HR 122.indd 271 www.500 units in 250 mL D5W is infusing at 15 mL per hr in a patient weighing 189 lb.000 (12.com 07/11/11 11:42 AM . The dosage of the infusion is adjusted over time based on the patient’s continued response to heparin (PTT monitoring). The hospital will provide a titration guideline for safe administration.7 units/kg/hr Weight-Based Heparin Protocol Many hospitals now use standard protocols (guidelines) based on the patient’s weight and blood results (PTT) to indicate a dosage range. How many units/kg/hr is the patient receiving? CONVERT LB TO KG: 1889 lb ÷ 2.ketabpezeshki. Lovenox and Fragmin are examples of low-molecular-weight anticoagulants. 500 = 750 units/h s r 250 7550 units/hr ÷ 86 kg = 8. See Table 13. The dosage is increased or decreased based on how close the blood levels are to the therapeutic PTT range.500 × 15) USING RATIO AND PROPORTION: CALCULATE UNITS/KG/HR: x= 187.CHAPTER 13 Heparin Preparation 271 EXAMPLE: H Heparin 12. (021) 66485438 66485457 LWBK914-C13_p258-279.500 units : 250 mL = x units : 15 mL 25500x = 187.7 units/kg/hr ANSWER: 8. 1 Weight-Based Heparin Protocol (DVT/PE) PTT less than 36 PTT 36 to 45 PTT 46 to 64 PTT 65 to 105 PTT 106 to 120 PTT 121 to 150 PTT greater than 150 Give 80 units per kg as a bolus. The Formula Method will be used here. Increase infusion rate by 4 units per kilogram per hour (4 U/kg/hr) Give 40 units per kilogram as a bolus.ketabpezeshki. calculate the bolus dose (units).com 07/11/11 11:42 AM . and calculate the infusion rate using one of the three standard methods of calculation. (021) 66485438 66485457 LWBK914-C13_p258-279. PA.272 UNIT 3 Dosage Calculations Table 13. Increase infusion rate by 2 units per kilogram per hour (2 U/kg/hr) Increase infusion rate by 1 unit per kilogram per hour (1 U/kg/hr) No change Decrease infusion rate by 1 unit per kilogram per hour (1 U/kg/hr) Decrease infusion rate by 2 units per kilogram per hour (2 U/kg/hr) Hold heparin for 1 hr and then decrease infusion rate by 3 units per kilogram per hour (3 U/kg/hr) Reprinted with permission from The Chester County Hospital. West Chester. Calculate IV Heparin Flow Rate (mL/hr) When Heparin Is Ordered According to a Weight-Based Protocol R U L E To give heparin according to a protocol: Convert the patient’s weight in pounds to kilograms.indd 272 www. com 07/11/11 11:42 AM .ketabpezeshki. Heparin is available as 25. 000 units 3 ×1 mL = mL = 0 6 mL 5.000 units per mL for a bolus dose.000 units per 500 mL NS. The nurse should give _____ mL as a bolus and set the infusion pump at _____ mL per hr.000 units Heparin is available as 5.2 lb/kg = 50 kg CALCULATE 600 units/kg × 50 kg = 3. 000 units 5 ANSWER: Give 0.000 units per 500 mL 50 USE THE FORMULA METHOD: D ×Q = x H CALCULATE UNITS/HR: 200 units/kg/hr × 50 kg = 1. START Sttart infusion at 20 units/kg/hr INFUSION: CALCULATE ML/HR: H Heparin is available as 25. CONVERT LB TO KG: 1110 lb ÷ 2.000 units/hr (021) 66485438 66485457 LWBK914-C13_p258-279.indd 273 www.6 mL for bolus dose.000 units/mL H BOLUS DOSE: USE THE FORMULA METHOD: D ×Q = x H 3.CHAPTER 13 Heparin Preparation 273 Thhe physician prescribed 60 units per kg of a heparin bolus for a patient who weighs 110 lb. The infusion is ordered at 20 units/kg/hr. Heparin is available as 5. 000 units 100 ANSWER: Give 0. Give a bolus dose of 80 units/kg (heparin is available as 10.indd 274 www.ketabpezeshki.200 units/hr (021) 66485438 66485457 LWBK914-C13_p258-279.800 units CALCULATE THE 80 BOLUS DOSE: Heparin is available as 10. The nurse should give __ mL as a bolus dose and set the infusion pump at ____ mL per hr.2 lb/kg = 60 kg 0 units/kg × 60 kg = 4. 000 units/h s r × 500 mL = 20 mL/hr 2 . CONVERT LB TO KG: 1332 lb ÷ 2.com 07/11/11 11:42 AM .274 UNIT 3 CALCULATE ML/HR: Dosage Calculations 1.48 mL as a bolus dose. EXAMPLE #2: A physician ordered heparin 12.500 units in 500 mL NS for a patient weighing 132 lb.000 units/mL) followed by an infusion of 20 units/kg/hr. 800 units 48 ×1 mL = = 0 48 mL 10 10. START INFUSION: 200 units/kg/hr × 60 kg = 1. 000 units 25 ANSWER: Set pump at 20 mL per hr.000 units H USE THE FORMULA METHOD TO D ×Q = x H CALCULATE BOLUS DOSE: 4. ketabpezeshki. 200 × 500 600.com 07/11/11 11:42 AM .CHAPTER 13 CALCULATE ML/HR: Heparin Preparation 275 D ×Q = x H 1.indd 275 www. 200 units/h s r × 500 mL = x 12. 500 units 48 1. (021) 66485438 66485457 LWBK914-C13_p258-279. 500 12. 000 = 12. 500 1 48 = = 48 mL/hr /h 1 ANSWER: Set the infusion pump at 48 mL per hr. 000 units of heparin added. Is the dosage within the normal. safe range for 24 hr? ______ 3. You have 1.com 07/11/11 11:42 AM . Calculate the flow rate. 276 (021) 66485438 66485457 LWBK914-C13_p258-279. Safe or unsafe? ______ 2.000 units of heparin to infuse at 20 mL per hr.000 mL of D5 NS with 40.ketabpezeshki. Give 1. Give 500 mL of D5 NS with 10. The physician prescribes a heparin bolus of 80 units per kg followed by an infusion of heparin 12. Is the dosage within the normal. Answer = ________ mL per hr 4.indd 276 www.000 units of heparin IV over 24 hr.500 units in 250 mL D5W to run at 18 units/kg/hr in a patient weighing 56 kg. Calculate the hourly dosage of heparin. You should administer _______ units IV push for the bolus and start the infusion at _______ mL per hr. safe range for 24 hr? Answer = _______ units per hr.000 mL of D5W with 10.End of Chapter Review Complete the following problems: 1. Give 800 units of heparin IV every hour. 000 units per milliliter.000 units of heparin subcutaneously at 8:00 am and 8:00 pm for 5 days.000 units per mL. The protocol directs you to increase the infusion by 2 units/kg/hr.ketabpezeshki.CHAPTER 13 Heparin Preparation 277 5. _____ 8. can you assume that the patient’s PTT result was equal to. This is/is not within the normal dosage range. The nurse should give _____ mL every 8 hr for a total dosage of _____ units per 24 hr. greater than.com 07/11/11 11:42 AM .indd 277 www. Heparin sodium for injection is available in a TUBEX Cartridge-Needle unit in 15. Heparin 12. A patient is to receive 10.500 units in 250 mL D5W is infusing at 21 mL per hr in a patient who weighs 92 kg. The results of a PTT blood test came back for the patient in Question #4.000 units. The nurse should give _____ mL every 12 hr for a daily total dosage of _____ units per 24 hr. Critical Thinking Check Since the infusion was increased. _____ (021) 66485438 66485457 LWBK914-C13_p258-279. How many units per kilogram per hour is the patient receiving at this flow rate? ___________ 7. is to be given subcutaneously every 8 hr. Less Than. The medication is available in a vial labeled 10. This is/is not within the normal dosage range. or Greater Than? 6. Heparin sodium. or less than the previous reading and the control? ________ Equal to. 8. After recalculating the rate you set the infusion pump at _______ mL per hr. every 8 hours.000 units per milliliter.000 units of heparin for injection intravenously through a heparin lock. The physician prescribed 1. (021) 66485438 66485457 LWBK914-C13_p258-279.000 units of heparin IV. Calculate the flow rate: _____ mL per hr. 11. The nurse should administer _____ mL. 12.000 units per 8 hr.000 units per 8 hr? 9. subcutaneously twice a day. The physician prescribed 5.45% NS with 15. Calculate the units per 24 hr: _____. The nurse should give _____ mL twice a day for a total dosage of _____ units per 24 hr. This is/is not within the normal dosage range.indd 278 www. _____ 10.com 07/11/11 11:42 AM . 13.500 units per milliliter.278 UNIT 3 Dosage Calculations Critical Thinking Check If an alternate dosage was prescribed for this patient.000 mL D5W with 10.000 mL of 0.ketabpezeshki. Heparin is available in a 10-mL vial in a concentration of 20.000 units of heparin to infuse at 10 mL per hr.000 units. or 15. Calculate the hourly dosage of heparin: _____ units per hr in 10 mL.000 units of heparin added. 12. You are to give 500 units of heparin IV hourly.000 units per 8 hr. safe or unsafe range? ______. 5. Heparin is available in a vial labeled 7. The physician prescribed heparin sodium. which daily dosage would you recognize as unsafe to give: ________ 10. The physician ordered 500 mL of D5W with 30. You have 1. Heparin 12.com 07/11/11 11:42 AM . You would document that the patient is receiving ____ units per kilogram per hour.500 units in 250 mL D5W) infusion for 1 hr and restart it at 10 units/kg/hr.com/Boyer8e.lww.ketabpezeshki. (021) 66485438 66485457 LWBK914-C13_p258-279. Using an infusion pump. the nurse should set the flow rate at _____ mL per hr to deliver _____ units per hr of heparin. A patient is to receive 500 mL of D5W with 15.500 units in 250 mL D5W is infusing at 15 mL per hr in a patient weighing 126 lb. how many mL per hr should the patient receive? _____ 16. 15.000 units of heparin over 24 hr.CHAPTER 13 Heparin Preparation 279 14. The activated PTT is elevated and the protocol directs you to hold the heparin (12. If the patient weighs 140 lb. Additional practice problems to enhance learning and facilitate chapter comprehension can be found on http://thePoint.indd 279 www. • Calculate oral and parenteral dosages based on body weight (mg/kg). 280 (021) 66485438 66485457 LWBK914-C14_p280-316.ketabpezeshki. you should be able to: • Convert weight in pounds to kilograms. • Calculate oral and parenteral dosages using body surface area (BSA). • Estimate body surface area using a nomogram and a formula. • Calculate intravenous flow rate.CHAPTER 14 Pediatric Dosage Calculations and Intravenous Therapy LEARNING OBJECTIVES After completing this chapter. • Calculate the lower and upper safe dosage ranges and total daily safe dosage.indd 280 www. kilograms to pounds.com 07/11/11 11:43 AM . and grams to kilograms. Parenteral medications are most commonly given subcutaneously (upper arm. Therefore. You should also use a calculator to double-check your calculations. and thigh) for immunizations and insulin and intramuscularly (vastus lateralis for infants and the gluteus after toddlers start walking) for vaccines. Dosages are calculated by either using body weight (mg/kg) or body surface area (BSA). A nurse must always determine that the ordered dosage is safe before administering the medication! Always compare the prescribed dosage to the recommended safe dosage range using a reference drug resource when calculating dosages. maturity of system.000 g = 1 kg). grams to kilograms (1. only two methods are currently used to calculate pediatric dosages. • Explain how to deliver IV push medications.com 07/11/11 11:43 AM . you need to become comfortable converting pounds to kilograms (1 kg = 2. children (1 to 12 years). and micrograms to milligrams (1.CHAPTER 14 Pediatric Dosage Calculations 281 • Calculate intermittent intravenous medication administration (intravenous piggyback [IVPB]). abdomen. and adolescents (13 to 18 years).000 mcg = 1 mg) and using a nomogram.2 lb). a cup can be used for school-age children. Orall pediatric medications are prescribed in liquid form whenever possible.indd 281 www. weight.ketabpezeshki. Because there are such variations among children (size. It is best to use a syringe or dropper to give medications to infants and toddlers. which is measured in square meters (m2). Dosage amounts are limited to 1 mL per site for those younger than 5 years of age (usually (021) 66485438 66485457 LWBK914-C14_p280-316.1. and medication rates of absorption). The West nomogram is shown in Figure 14. E xtreme care must be taken when preparing and administering medications to infants (birth to 12 months). The nomogram on page 000 indicates 1. North Chicago.ketabpezeshki.5 mL for infants). IL. Children ages 6 to 12 years can be given up to 2 mL of solution per site. Refer to Appendix E for information on subcutaneous injections and Appendix H for pediatric intramuscular (021) 66485438 66485457 LWBK914-C14_p280-316.indd 282 www.com 07/11/11 11:43 AM .05 m2 surface area for a child who weighs 75 lb and is 4 feet. and the quantity is measured using a tuberculin syringe.1 Nomograms for estimating body surface area. the volume limit for adolescents is 3 mL per site.) 0. (Illustrations courtesy of Abbott Laboratories. 2 inches tall.282 UNIT 3 Dosage Calculations FIGURE 14. Appendix I covers nursing concerns for pediatric drug administration. a (021) 66485438 66485457 LWBK914-C14_p280-316.CHAPTER 14 Pediatric Dosage Calculations 283 FIGURE 14. It is essential that pediatric intravenous therapy be as exact as possible because infants and children have a narrow range of fluid balance.indd 283 www.1 (continued) injections.com 07/11/11 11:43 AM . Therefore.ketabpezeshki. To convert kilograms to pounds: Multiply the patient’s body weight in kilograms by 2. Note: If a child’s weight is in pounds and ounces.2 lb in 1 kg.284 UNIT 3 Dosage Calculations microdrip. (021) 66485438 66485457 LWBK914-C14_p280-316.2. estimate to the nearest tenth of a pound and add that number to the total pounds. Note: For premature infants. EXAMPLE #1: Convert a child’s weight of 44 lb into kilograms. IV solution volume. Remember: Total fluid volume consists of medication diluent volume.com 07/11/11 11:43 AM . you will probably need to work with grams (1. An intravenous infusion rate is calculated in both drops per minute (i.000 g = 1 kg). via a Buretrol) and milliliters per hour using a microdrip or an electronic infusion pump. There are 2. Weight Conversions Convert Weight in Pounds to Kilograms and Kilograms to Pounds When medications are prescribed in milligrams per kilogram (mg/kg) of body weight. volume-controlled set (Buretrol) or a pump should be used. you must convert pounds to kilograms before calculating the dosage. or dimensional analysis.e. R U L E To convert pounds to kilograms: Divide the patient’s body weight in pounds by 2. ratio and proportion.2. and flush volume (5 mL to 20 mL).ketabpezeshki.indd 284 www.. Use one of these three methods for calculation of dosages: simple division or multiplication. indd 285 www. (quo 22 440. 44.2 × 20 = 440 20 = = 20 22 1 1 ANSWER: 20 kg (021) 66485438 66485457 LWBK914-C14_p280-316. ) ANSWER: 20 kg Ratio and Proportion 2.2 lb 2.2x 2 = 44 20 x= 44 440 20 = = = 20 2.2 lb 44 lb 1 kg 44 × 1 ( kg) = × = 2.2 lb : 1 kg = 44 lb : x kg 2.com 07/11/11 11:43 AM .CHAPTER 14 Pediatric Dosage Calculations 285 Basic Division Move the decimal point in the divisor and the dividend the same number of places.0. Put the decimal point directly above the line for the quotient. ( tient) 20.2 22 1 1 ANSWER: 20 kg Note: Move the decimal point in the denominator and the numerator the same number of spaces prior to doing the cancellation. Dimensional Analysis 44 lb 1 kg 2.2. ) 2.ketabpezeshki. EXAMPLE #2: C Convert a child’s weight of 25 kg to pounds.2 x = 55 pounds ANSWER: 55 lb Dimensional Analysis 25 kg = × 2.com 07/11/11 11:43 AM .000 and round to the nearest tenth.2 lb × 25 kg/lb = 55 lb ANSWER: 55 lb Ratio and Proportion 2. (021) 66485438 66485457 LWBK914-C14_p280-316.2 lb 1 kg 25 kg × 2.2 = = 55 1 kg 1 ANSWER: 55 lb Convert Weight in Grams to Kilograms R U L E To convert grams to kilograms for infants: Divide the infant’s body weight (in grams) by 1.ketabpezeshki.2 lb : 1 kg = x lb : 25 kg x = 25 × 2. Basic Multiplication 2.indd 286 www.286 UNIT 3 Dosage Calculations Note: Move the decimal point in the denominator and the numerator the same number of spaces prior to doing the cancellation.2 (lb) 255 × 2. 000 g = x kg : 2. or an institutional protocol.000x 0 = 2.3 kg Estimate Safe Total Daily Dosage Pediatric medications have an upper and a lower safe dosage range used to indicate a safe. 000 ANSWER: 2.indd 287 www. 270 g = 1 kg 1.com 07/11/11 11:43 AM .270 x= 2.27 kg 1. (021) 66485438 66485457 LWBK914-C14_p280-316.CHAPTER 14 EXAMPLE: Pediatric Dosage Calculations 287 C Convert an infant’s weight of 2.3 kg Dimensional Analysis 2. You can find this information on the drug package insert. 000 g × 1 kg 2. 270 g × 2. Ratio and Proportion 1 kg : 1. total daily dose.27 1. a drug reference. You need this information before you calculate any dose to give to a child.ketabpezeshki. 000 g 1.270 g to kilograms. 270 = 2. 000 ANSWER: 2.000 2. 2270 1 ( kg) = 1. 270 = 2.270 g 1. 5 mg/dose Determine: Dose of 10 mg. is safe.indd 288 www.5 mg/kg/day Estimate: 2.ketabpezeshki. q6h. The safe daily dosage is 2. total. (021) 66485438 66485457 LWBK914-C14_p280-316. EXAMPLE #1: A child weighs 15 kg.5 mg × 20 kg = 50 mg.5 mg/kg/day. daily dosage: Multiply the patient’s weight in kilograms by the recommended dosage in milligrams.com 07/11/11 11:43 AM . Estimate Total Daily Dosage 4 mg × 15 kg = 60 mg/day ANSWER: Total daily dosage = 60 mg per day EXAMPLE #2: A child weighs 20 kg. divided into 4 doses = 12.288 UNIT 3 Dosage Calculations R U L E To calculate safe. R U L E To calculate the safe lower and upper dosage range: Multiply the child’s weight in kilograms by the lower and upper dosage ranges in milligrams: milligrams per kilogram per day (mg/kg/day) or milligrams per kilogram per dose (mg/kg/dose). The safe daily drug dosage is 4 mg/kg/day. Estimate Total Daily Dosage 10 mg × 4 doses = 40 mg/day (24 hr ÷ 6 = 4 doses/day) Determine If the Prescribed Dose Is Safe Safe dosage is: 2. The physician orders 10 mg of a drug every 6 hr. Calculate the lower and upper dosage ranges. q8h. for a child who weighs 30 kg.2). calculate safe dosage range.com 07/11/11 11:43 AM .ketabpezeshki. The total daily dosage of 225 mg is safe. compare the prescribed dosage with the safe dosage range.CHAPTER 14 EXAMPLE: Pediatric Dosage Calculations 289 A physician orders 75 mg of an antibiotic. and calculate! (021) 66485438 66485457 LWBK914-C14_p280-316. Remember the sequence of activities: convert. ESTIMATE TOTAL DAILY DOSAGE: 75 mg × 3 doses (24 hr ÷ 8 hr) = 225 mg CALCULATE 6 mg/kg/day × 30 kg = 180 mg LOWER DOSE RANGE: CALCULATE 8 mg/kg/day × 30 kg = 240 mg UPPER DOSE RANGE: DETERMINE IF DOSE IS SAFE: Yes. compare. calculate. and calculate the dose needed using one of three calculation methods.indd 289 www. The safe dosage range is 6 to 8 mg/kg/day. Calculate Oral and Parenteral Dosages Based on Body Weight (mg per kg) R U L E To calculate dosage based on body weight: Convert pounds to kilograms (divide by 2. Ratio and Proportion 250 mg : 10 mL = 400 mg : x mL 250x 0 = 4. Therefore.ketabpezeshki. twice daily. it is a safe dose to give. The patient weighs 44 lb.indd 290 www. The nurse should give x mL.2 lb/kg = 20 kg CALCULATE Thhe safe dosage range is 20 to 40 mg/ kg kg/day.000 16 x= 4. The antibiotic is available as 250 mg per 10 mL. 000 16 = = 16 mL 250 1 1 ANSWER: 16 mL (021) 66485438 66485457 LWBK914-C14_p280-316. C Calculate mL to give by using one of the thhree calculation methods. 20 kg × 20 mg (low range) = 400 mg 20 kg × 40 mg (high range) = 800 mg The safe dosage range for this child is 400 to 800 mg per day. 20 mg/kg/day. The safe dosage range for the antibiotic is 20 to 40 mg/kg/day.com 07/11/11 11:43 AM . PO. SAFE DOSAGE: COMPARE PRESCRIBED DOSE WITH SAFE DOSE: CALCULATE THE DOSE: Thhe prescribed dose is 20 mg/kg/day or 4000 mg daily. Thhis dose is within the lower range of safe dosage.290 UNIT 3 Dosage Calculations EXAMPLE #1: Th he physician prescribed an antibiotic. CONVERT: 44 lb to kilograms 44 lb ÷ 2. indd 291 www.2 lb/kg = 15 kg. q8h for a 33-lb child. (021) 66485438 66485457 LWBK914-C14_p280-316.CHAPTER 14 Pediatric Dosage Calculations 291 The Formula Method Use D ×Q = x H 400 mg ×10 mL = x 250 mg 16 400 4. PO. The antibiotic is available as 250 mg per 5 mL. 000 16 ×10 mL = = = 16 mL 250 250 1 1 ANSWER: 16 mL Dimensional Analysis 400 mg = 400 mg 10 mL 250 mg = 10 ( ) 400 10 ( = 250 mg 250 16 = 4.com 07/11/11 11:43 AM . three times daily. The safe dosage range is 20 to 40 mg/kg/ day. 000 2250 50 1 = ) 16 = 16 mL 1 ANSWER: 16 mL EXAMPLE #2: Th he physician prescribed 125 mg of an antibiotic. CONVERT: 333 lb to kilograms 33 lb ÷ 2. The nurse should give x mL.ketabpezeshki. it is a safe dose to give.ketabpezeshki. Therefore. This dose is within the safe dosage range. PRESCRIBED DOSE WITH SAFE DOSE: The prescribed dose is 125 mg.com 07/11/11 11:43 AM .292 UNIT 3 CALCULATE SAFE DOSAGE: Dosage Calculations Thhe safe dosage range is 20 to 40 mg/ kg kg/day. q8h. T CALCULATE THE DOSE: C Calculate mL to give by using one of the three calculation methods. 15 kg × 20 mg (low range) = 300 mg 15 kg × 40 mg (high range) = 600 mg The safe dosage range for this child is 300 to 600 mg per day. th COMPARE Ratio and Proportion 125 mg : x mL = 250 mg : 5 mL 250x 0 = 625 (5 × 125) x= 625 = 2 5 mL 250 ANSWER: 2.5 mL per 8 hr (021) 66485438 66485457 LWBK914-C14_p280-316.indd 292 www.5 mL per 8 hr The Formula Method Use D ×Q = x H 125 mg ×5 = x 250 mg 1 125 5 × 5 = = 2 5 mL 250 2 2 ANSWER: 2. orr 375 mg daily. There are two ways to estimate BSA.5 5 mL 250 ANSWER: 2. EXAMPLE #1: A child weighs 24 lb and is 36 inches tall. The line will intersect at 0. 600 (021) 66485438 66485457 LWBK914-C14_p280-316.com 07/11/11 11:43 AM .1)—or a formula that uses the metric system but requires a calculator that can perform the square root function.CHAPTER 14 Pediatric Dosage Calculations 293 Dimensional Analysis 125 mg × 125 mg = 5 mL 250 mg × 5 (mL)) 125 × 5 (mL) = 250 mg 250 625 = 2. is the most accurate way of calculating drug dosages. You can use a chart—the West nomogram (Figure 14.5 m2 EXAMPLE #2: A child weighs 50 lb and has a height of 40 inches.5 mL per 8 hr Estimate Body Surface Area Estimating body surface area (BSA). in square meters (m2). draw a line from the weight of 24 lb and the height of 36 inches. What is the BSA? USE THIS FORMULA: Weight (kg) ( × height (cm) =x 3.ketabpezeshki. To estimate BSA. ANSWER: BSA = 0.5 m2.indd 293 www. and multiply by the adult dose.5 cm CONVERT 40 INCHES TO 40 0 inches × 2.indd 294 www. 600 0 63 ANSWER: BSA = 0. (021) 66485438 66485457 LWBK914-C14_p280-316.294 UNIT 3 TAKE THE SQUARE ROOT: Dosage Calculations x = BSA CONVERT 50 LB 1 kg = 2.2 lb TO KILOGRAMS: 50 0 lb ÷ 2.com 07/11/11 11:43 AM . 600 TAKE SQUARE ROOT: = 2.7 kg 1 inch = 2.ketabpezeshki.7 ( kg) 100 (cm ) 3. Rule #2 is the most accurate approach.79 Dosage Calculations Based on Body Surface Area There are two rules that can be used.5 cm/inch = 100 cm CENTIMETERS: APPLY FORMULA: 22. 270 = 0 63 3.73 m2 (surface area of an average adult). R U L E #1 To calculate a safe child’s dosage when you only have the average adult dose: Estimate the child’s BSA.2 lb/kg = 22. divide the child’s BSA in square meters (m2) by 1. The medication is available as a scored 5-mg tablet. USE BODY SURFACE AREA RULE: Child’s BSA C × adult dose 1. decide if the prescribed dose is within the safe dosage range. q. DETERMINE BSA: Draw a straight line from the height of 34 inches to the weight of 25 lb.i. R U L E #2 To calculate a safe child’s dosage: Determine the patient’s BSA (m2). using the West nomogram.d. The nurse should give x mg. calculate the safe dosage in mg/m2/dose using a reference. The line intersects at 0.com 07/11/11 11:43 AM . intersects at 1.i.CHAPTER 14 Pediatric Dosage Calculations 295 EXAMPLE #1: Th he physician prescribed Benadryl for an 8-year-old child who weighs 75 lb and is 50 inches tall (4 feet. 2 inches). and calculate the dose needed using one of the three calculation methods.5 m2. (021) 66485438 66485457 LWBK914-C14_p280-316.ketabpezeshki. The nurse should give x tablets per dose. q.73 m 2 g 15 17 mg ANSWER: 15 mg.indd 295 www. q. PO. The medication label lists a safe dosage range of 10 mg/m2/day.73 m 2 1 05 m 2 = 0 06 25 1. The normal adult dose is 25 mg. EXAMPLE #2: The physician prescribed 2.i. for 5 days for a child who is 34 inches tall and weighs 25 lb. A straight line drawn from height to weight.5 mg of an antibiotic.05 m2.d. twice daily.d. 5 m2 = 5 mg/day Thhe prescribed dose is 2.com 07/11/11 11:43 AM . Th So for x using one of the three calculaSolve tioon methods.5 1 25 1 = tabl a et 52 2 x= ANSWER: ½ tablet.5 mg. it is a safe dose to give.indd 296 www. which falls within the safe dosage range w off 5 mg per day. Ratio and Proportion 5 mg : 1 tablet = 2. q12h. q12h The Formula Method D ×Q = x H 2 5 mg ×1 tabl a et = x 5 mg 1 25 1 = tabl a et 52 2 ANSWER: ½ tablet. q12h (021) 66485438 66485457 LWBK914-C14_p280-316.ketabpezeshki.296 UNIT 3 CALCULATE SAFE DOSAGE: COMPARE PRESCRIBED DOSE WITH SAFE DOSE: CALCULATE THE DOSE: Dosage Calculations Thhe safe dosage range is 10 mg/m2/day 10 mg × 0. Therefore.5 mg : x 5x = 2. The nurse gave _________ mg. If the nurse gave 30 mg per dose. would this be a safe dose? Yes ____ or No _____ 3.indd 297 www. If the nurse gave 275 mg per dose. q12h PRACTICE PROBLEMS 1.ketabpezeshki.CHAPTER 14 Pediatric Dosage Calculations 297 Dimensional Analysis 2 5 mg = × 1 tablet 5 mg 2 5 mgg × 1 tabl a et 2 5 ×1 ( bl ) = 5 mg 5 1 = 25 1 = tabl a et 52 2 ANSWER: ½ tablet. six times a day. A physician prescribed codeine 30 mg.com 07/11/11 11:43 AM . The safe dosage is 15 mg/kg/day. The safe dosage range is 0. A physician prescribed Biaxin 275 mg. PO. for a child in pain. for a 44-lb child with pneumonia. Is this a safe dose? Yes ____ or No _____ (021) 66485438 66485457 LWBK914-C14_p280-316. An emergency department physician ordered 4 mg of a drug for a 44-lb child with a seizure. would this be a safe daily dose? Yes ____ or No _____ 2. q8h. The child weighs 44 lb.04 to 0. q4h. The safe dosage is 5 to 10 mg/kg/dose. as needed.2 mg/kg/dose. PO. A physician prescribed Dilantin 50 mg. for an 88-lb child. the safe dosage range for this teenager is _________ g/day. The child weighs _________ kg. Augmentin is labeled 250 mg per 5 mL. q8h.indd 298 www. q6h. PO. for a child with otitis media. The safe dosage range is 25 to 50 mg/kg/24 hr. q8h. The child weighs _________ kg. PO. If the nurse gave 1 g per dose. q12h. PO. A physician ordered penicillin V potassium 375 mg. The child weighs _________ kg.com 07/11/11 11:43 AM . q6h. the safe dosage range for this child is _________ mg per dose. 5. would this be safe? Yes _____ or No _____ 7.298 UNIT 3 Dosage Calculations 4. Is this a safe dose? Yes ____ or No _____ 8. The dosage range for this child is _____________ mg per day. for a 132-lb teenager. The safe dosage range is 5 to 7 mg/kg/day. The physician ordered Augmentin Suspension 550 mg. The dosage range for this child is _________ mg per day. The safe dosage range is 50 to 100 mg/kg/ day. Is this a safe dose? Yes ____ or No ____ (021) 66485438 66485457 LWBK914-C14_p280-316. for a 66-lb child. The nurse should administer _________ mL. If the nurse gave 60 mg per dose.ketabpezeshki. The physician prescribed nafcillin 1 g. for a 33-lb child with a seizure disorder. Therefore. The teenager weighs _________ kg. would this be a safe dose? Yes ____ or No _____ 6. Therefore. The physician prescribed 60 mg of a drug. q6h. The safe dosage range is 5 to 10 mg/kg/day. The nurse would give _____ mL per dose. for temperature greater than 101. The safe dosage range for this child is _________ mg per day. If the nurse gave 30 mg per day.8 mL. for a 44-lb child. The physician ordered ranitidine HCl 15 mg. q12h. The safe dosage range is 5 to 10 mg/kg/day. A physician ordered Orapred liquid 20 mg. PO.n. Is this a safe dose? Yes ____ or No _____ 10. The safe dosage range is 0. PO.5 to 2 mg/kg/day. If the nurse gave 50 mg per dose.CHAPTER 14 Pediatric Dosage Calculations 299 9. The physician prescribed Tylenol drops 100 mg. The child weighs _________ kg.ketabpezeshki. The safe dosage range for this teenager is ______ mg per day. The safe dosage range is 0. A physician prescribed Accutane 50 mg. The safe dosage range is 10 to 15 mg/kg/dose. Tylenol drops are available as 80 mg per 0. Orapred liquid is labeled as 5 mg per mL. Is this a safe dose? Yes _______ or No ______ (021) 66485438 66485457 LWBK914-C14_p280-316. q12h.indd 299 www. PO. The safe dosage range for this child is ______ mg per day. for acne for a 110-lb teenager.4°F for an infant who weighs 8 kg. twice a day. would this be a safe dose? Yes ____ or No _____ 11.. would this be a safe dose? Yes _____ or No _____ 12. The dosage range for this infant is ______ mg per dose.r. q4h. for a 5-kg infant with gastroesophageal reflux disease (GERD). The nurse would give _______ mL of Tylenol. p. PO.5 to 2 mg/kg/day.com 07/11/11 11:43 AM . Buretrol) is used when the total volume is (021) 66485438 66485457 LWBK914-C14_p280-316.g. Tylenol drops are available as labeled 80 mg per 0.8 mL. Calculate Intravenous Flow Rate An infusion pump or volume-controlled unit is always used for pediatric intravenous therapy to reduce the possibility of fluid overload. The normal adult dose is 650 mg.300 UNIT 3 Dosage Calculations 13. The nurse should administer _______ mg each dose. The safe dosage range is 20 to 40 mg/kg/day. PO..indd 300 www.com 07/11/11 11:43 AM . The nurse should administer _____ mL. The label on the vial is Rocephin 500 mg per 2.5 mL. A 4-year-old is prescribed one dose of Rocephin 300 mg.ketabpezeshki. for a 33-lb toddler. The physician prescribed Ceclor 200 mg. The dosage range for this toddler is ________ mg per day. Using BSA. calculate a physician order of Tylenol drops for a 6-year-old who weighs 50 lb and is 36 inches tall. IM. every 8 hr. Is this a safe dose? Yes _______ or No _______ Critical Thinking Check If the physician increased the dosage of Ceclor to 300 mg per 8 hr. 15. would the dosage be within a safe range to give? ________ Yes or No? 14. The volume-controlled unit (e. The child’s BSA = ______ m2. You should administer _______ mL. It is essential that pediatric intravenous therapy be as exact as possible because infants and children have a narrow range of fluid balance. 000 240 x = 50 mL/hr x= ANSWER: Set pump to deliver 50 mL per hr (021) 66485438 66485457 LWBK914-C14_p280-316. USE THIS FORMULA: Total volume x (mL/hr) = T tal time (mi To ( nutes) 60 min 200 mL x (mL/hr) = 240 min 60 min 240x 0 = 12. EXAMPLE: G 200 mL of NS over 4 hr to a 5-yearGive old child.000 12. The guidelines for regulating flow rate and mL/hr using a pump or control unit are the same for a child as for an adult (see Chapter 10). IV tubing with a drop factor of 60 gtt per mL is recommended (required for infants and small children) because the amount of IV volume is less than that prescribed for adults. the rates must be closely monitored to prevent fluid overload.com 07/11/11 11:43 AM . with children.indd 301 www. An infusion pump is used. However.ketabpezeshki. The primary caution in administering IV medications to pediatric patients is the amount of fluid volume that is used.CHAPTER 14 Pediatric Dosage Calculations 301 less than 150 mL. (021) 66485438 66485457 LWBK914-C14_p280-316. These control devices reduce the possibility of fluid overload. Follow institutional guidelines for IV flush. • Calculate the safe dosage range. Additional information about IVPB delivery can be found in Chapter 10. R U L E To calculate an IVPB medication: • Convert the child’s weight from pounds to kilograms. • Compare the prescribed dose of medication with the safe dosage. Most drugs are available in a powder that comes premixed and has to be reconstituted (diluted) using a prescribed type and amount of diluent. and flush volume (5 to 10 mL). • Calculate the flow rate and set the pump to mL per hr. Always follow the manufacturer’s dilution requirements! Some institutions provide standard guidelines to assist the nurse in preparing IV pediatric dosages.indd 302 www.ketabpezeshki.302 UNIT 3 Dosage Calculations Calculate Intermittent Intravenous Medication Administration (Intravenous Piggyback: IVPB) Dosages for IV medications are based on weight and calculated in mg per kg.com 07/11/11 11:43 AM . Use a reference. • Calculate the amount of medication to be given. Solusets. IV solution volume. the total fluid volume consists of medication diluent volume. • Flush tubing with 5 mL to 20 mL of flush solution and chart fluid intake. • Verify the type and amount of diluent for reconstitution. Always remember! When administering IV medications. or other volume-controlled infusion sets/pumps are always used to regulate the infusion. • Add IV solution and medication to Buretrol. See Figure 14.2. Buretrols. . P.]. Fundamentals of nursing: The art and science of nursing care [6th ed. and LeMone.indd 303 www. Lillis. [2008].ketabpezeshki. IV. The antibiotic is available as 250 mg per (021) 66485438 66485457 LWBK914-C14_p280-316.CHAPTER 14 Pediatric Dosage Calculations 303 FIGURE 14. C.com 07/11/11 11:43 AM . C.2 Volume-controlled set.. Follow with a 10-mL NS flush. q6h. via a Buretrol. in 50 mL of NS to infuse over 30 min. (From Taylor.) EXAMPLE #1: The physician prescribed 125 mg of an antibiotic to be given. Philadelphia: Lippincott Williams & Wilkins. 000 mg/day Thhe prescribed dose is 125 mg. Set the pump for a flow rate of x mL per hr. Therefore.indd 304 www. C ONVERT : 444 lb to kilograms 44 lb ÷ 2.000 mg SAFE DOSAGE: COMPARE PRESCRIBED DOSE WITH THE SAFE DOSE: CALCULATE THE DOSE: Thhe safe dosage range for this child is 5000 to 1. Soolve for x using one of the three calculattion methods. the prescribed dosage is within the safe dosage range. q6h.2 lb/kg = 20 kg CALCULATE Thhe safe dosage range is 25 to 50 mg/ kgg/day. The child weighs 44 lb. 25 mg (lower range) × 20 kg = 500 mg 50 mg (upper range) × 20 kg = 1.com 07/11/11 11:43 AM . Ratio and Proportion 250 mg : 4 mL = 125 mg : x mL 250x 0 = 500 (125 × 2) 2 x= 500 2 = = 2 mL 250 1 1 ANSWER: x = 2 mL (021) 66485438 66485457 LWBK914-C14_p280-316. Is the prescribed dose within the safe dosage range? The nurse should give x mL of the antibiotic. q6h.ketabpezeshki. in 50 mL of D5W over 30 min. which h equals 500 mg per day.304 UNIT 3 Dosage Calculations 4 mL with a safe dosage range of 25 to 50 mg/kg/24 hr. Allow 48 mL of NS to run into the Buretrol and then add 2 mL of the antibiotic.indd 305 www. you would prepare 2 mL of the antibiotic. CALCULATE THE Usse the Standard Formula to determine FLOW RATE: mL L/hr. Total volume Drop fact f or = mL/hr Total time in minutes e 50 × 60 3.CHAPTER 14 Pediatric Dosage Calculations 305 The Formula Method D ×Q = x H 125 mg × 4 mL = x 250 mg 2 x= 125 × 4 500 2 = = = 2 mL 250 250 1 1 ANSWER: x = 2 mL Dimensional Analysis 125 mg 125 × × 4 mL 250 mg 4 (mL) 4 ( ) 125 = 250 250 2 = 500 2 = = 2 mL 250 1 1 ANSWER: x = 2 mL ADD IV SOLUTION: Too give 125 mg.com 07/11/11 11:43 AM .ketabpezeshki. 000 = = 100 mL/hr 30 30 (021) 66485438 66485457 LWBK914-C14_p280-316. so (021) 66485438 66485457 LWBK914-C14_p280-316. FLUSH TUBING: Flu ush the tubing with 10 mL of NS.306 UNIT 3 Dosage Calculations SET THE PUMP: To o deliver 125 mg in 50 mL NS. or 1. Thhis dose is within the safe dosage range. add 2 mL of sterile water for a solution of 200 mg per mL. via a Buretrol. To dilute. Th dd 2 mL of sterile water to the vial for a VERIFY AMOUNT Ad OF DILUENT: solution of 200 mg/mL. EXAMPLE #2: A 4-year old child who weighs 55 lb is prescribed 250 mg of an antibiotic to be given IVPB. in 50 mL of NSS.ketabpezeshki. Infuse over 30 min.com 07/11/11 11:43 AM .indd 306 www. The antibiotic is available as a powder labeled 500 mg.500 mg/day SAFE DOSAGE: COMPARE PRESCRIBED DOSE WITH SAFE DOSE: Thhe prescribed dose is 250 mg. it is a safe dose to give.000 mg daily. The Buretrol is connected to a pump. Use 20 mL as a flush solution.2 lb/kg = 25 kg CALCULATE Thhe safe dosage range is 30 to 60 mg/ kg/24 hr kg 25 kg × 30 mg (low range) = 750 mg 25 kg × 60 mg (high range) = 1. CONVERT: 555 lb to kilograms 55 lb ÷ 2. q6h. The safe dosage range is 30 to 60 mg/kg/24 hr. CHART FLUID INTAKE: Chhart the intake of 60 mL (48 + 2 + 10). q6h. set the pump to 100 mL/hr. Therefore.500 mg The safe dosage range for this child is 750 to 1. 25 mL 200 4 4 ANSWER: 1.25 mL (021) 66485438 66485457 LWBK914-C14_p280-316.25 mL 200 4 4 ANSWER: 1.25 mL The Formula Method D ×Q = x H 250 mg ×1 mL = x 200 mg 5 250 5 = = 1.indd 307 www. Ratio and Proportion 250 mg : x = 200 mg : 1 mL 200x 0 = 250 5 x= 250 5 = = 1.CHAPTER 14 CALCULATE THE DOSE: Pediatric Dosage Calculations 307 Soolve for x using one of the three calculatioon methods.com 07/11/11 11:43 AM .25 mL 200 4 4 ANSWER: 1.ketabpezeshki.25 mL Dimensional Analysis 250 mg 250 mg × 1 mL 200 mg × 1 (mL) 250 ×1 (mL) = 200 mg 200 5 = 250 5 = = 1. com 07/11/11 11:43 AM . how fast to push the drug. Total volume mL/hr = Total time in minutes 60 min i 50 mL x mL = 30 min 60 min 30x 0 = 3.indd 308 www.000 x = 100 mL SET THE PUMP: Seet the infusion pump to 100 mL/hr.75 + 1.ketabpezeshki. FLUSH TUBING: Flu CHART FLUID INTAKE: Chhart an intake of 70 mL (48. your next step would be to determine. The pump will deliver 50 mL in 30 min. It is important to push the drug slowly over the required time period. ush the tubing with 20 mL of NSS. When the infusion time is less than 60 min. Usse the standard formula. Because you would be pushing the medication into the vein. add 60 min sio as a conversion factor.25 mL of meedication to the Buretrol.75 mL of NSS plus 1.308 UNIT 3 ADD IV SOLUTION: CALCULATE THE FLOW RATE: Dosage Calculations Addd 48. monitoring the (021) 66485438 66485457 LWBK914-C14_p280-316. from the order or a standard reference.25 + 20) Calculate IV Push Medications To calculate the amount of medication to prepare for an IV push delivery. follow the first five steps in the foregoing rule. if a drug is to be infused over 2 min. twice. It is also important to pace the delivery so half is pushed in over half the time. For example.ketabpezeshki.CHAPTER 14 Pediatric Dosage Calculations 309 patient for any adverse reactions.com 07/11/11 11:43 AM . (021) 66485438 66485457 LWBK914-C14_p280-316. Refer to a more detailed explanation of this in Chapter 10. you should divide the volume and the time in half and count for 1 min.indd 309 www. 25 mg/kg for a 22-lb.ketabpezeshki. A physician prescribed Keflex 150 mg. This is/ is not within a safe range.End of Chapter Review Complete the following problems: 1. The nurse should give _____ mg preoperatively. 4. 3. The child’s weight is _____ kg.5 to 2. PO.0 mg/kg/day. The child weighs 33 pounds. Phenergan is to be given as 1 mg/kg of body weight. A physician prescribed Phenergan for preoperative medication for a 44-lb child. for a 22-lb child. The safe dosage range is 25 to 50 mg/kg/day. 12-month-old child. The safe dosage range is 0. every 12 hours.com 07/11/11 11:43 AM . The child should receive ______ mL/q6h. This is/is not within a safe range. The physician prescribed 10 mg of an antibiotic. the safe dosage range for this child per day is ___________ mg. q6h. Keflex is labeled 125 mg per 5 mL. ________ 310 (021) 66485438 66485457 LWBK914-C14_p280-316. The dosage range for this child is _____ mg per day. The medicine was to be given q12h. The child should receive _____ mg per dose. every 12 hr.indd 310 www. The physician prescribed an antibiotic. ______ 2. PO. ________ Critical Thinking Check If the child gains 4 lb. Calculate the dosage the child should receive in four equally divided doses.22 m2.indd 311 www. You should administer ______ mL. for a 66-lb child. Morphine sulfate is available in 10 mg per 2 mL. The child weighs 90 lb and is 52 inches tall (4 feet. Calculate the dosage to administer using a BSA of 1. The child should receive ________ mg/day. A physician prescribed a medication for a 7-year-old who weighs 70 lb and is 50 inches tall. 4 inches). Determine the BSA: _____. ______ (021) 66485438 66485457 LWBK914-C14_p280-316. The child’s weight is _____ kg. the safe dosage range for this child/day is _________ mg. A 10-year-old is ordered a stat dose of morphine sulfate IV for pain. The safe dosage range is 3 to 5 mg/kg/day. The normal adult dose of morphine sulfate is 10 mg.1 to find the child’s surface area in square meters. A physician prescribed phenobarbital 50 mg.com 07/11/11 11:43 AM . Refer to the nomogram in Figure 14. This is/is not within a safe range. q12h. 7.ketabpezeshki. would the dosage per day be within a safe range to give? ________ Yes or No? 6. The normal adult dose is 50 mg every 6 hr.CHAPTER 14 Pediatric Dosage Calculations 311 5. You should administer ________ mg of morphine sulfate. Is this a safe dose? Yes ____ or No _____ (021) 66485438 66485457 LWBK914-C14_p280-316. The physician prescribed 5 mg of Garamycin for a child. Is this a safe dose? Yes ___ or No ____. The safe dosage range is 20 to 40 mg/kg/day. for a 44-kg child.ketabpezeshki. 11. every 6 hr postoperatively. once a day for an 11-lb infant.com 07/11/11 11:43 AM . The physician prescribed amoxicillin suspension 225 mg. you should give _______ mL. The physician prescribed Ceclor 300 mg. The nurse would give ____ mL per dose. The safe dosage is 15 mg/kg/day. The physician prescribed 20 mg of Demerol. The safe dosage range is 25 to 50 mg/kg/day. The medication is available as 20 mg per 2 mL. q12h. for a 66-lb child. PO. The safe dosage range for this child is _____ mg per day. 10. The safe dosage range is 5 to 10 mg/kg/dose. to a 7-year-old child.312 UNIT 3 Dosage Calculations 8. The physician prescribed 325 mg of a suspension. Is this a safe dose? Yes _____ or No _____ 12. Is this a safe dose? Yes ____ or No _____ 13. PO. The nurse would give _______ mg per day. q8h. for a 33-lb child. The safe dosage range for this child is _____ mg/day. PO. The physician prescribed caffeine citrate 30 mg. The suspension is available as 500 mg per mL. 9. PO. Demerol is available as 25 mg per mL. You should give _______ mL/6 hr after verifying that the dose is safe.indd 312 www. q8h. To give 5 mg. The nurse would give _____ mL each morning. PO. You would administer _______ mL. The physician prescribed Lasix 5 mg.com 07/11/11 11:43 AM . Gentamicin is available as 20 mg per mL. for an 88-lb child. for a 33-lb child. Is this a safe dose? Yes ______ or No ______ 18. PO. PO.3 mg/kg/24 hr. The safe dosage is 2. q12h.ketabpezeshki.5 to 2 mg/kg/ day. Is this a safe dose? Yes ____ or No _____ 15. The nurse would give _____ mg per dose. The physician prescribed Depakene 1 g. for an 11-lb infant with a cardiac problem. every morning.indd 313 www. IV.CHAPTER 14 Pediatric Dosage Calculations 313 14. The physician prescribed Aldactone 20 mg. ______ (021) 66485438 66485457 LWBK914-C14_p280-316. The safe dosage range is 0. PO. q8h.5 mg/kg/dose. Is this a safe dose? Yes _____ or No _____ 17. The safe dosage range is 30 to 60 mg/kg/day. The safe dosage range for this child is ____ mg per dose. The safe dosage range is 1 to 3. The safe dosage range is 25 to 50 mg/kg/dose. q12h. for one dose for an 11-lb infant prior to an EEG study. Is this a safe dose? Yes ____ or No _____ 16. This is/is not a safe dose. The safe dosage range for this child is ____ mg per dose. The physician prescribed gentamicin 12 mg. q8h. Lasix liquid is labeled 10 mg per mL. The safe dosage range for this child is ______ mg per dose. The physician prescribed chloral hydrate 400 mg. for an infant who weighs 6 kg. 5 to 2 mg/kg/dose. the safe dosage range for this child is _______________ mg/dose. the safe dosage range for this child is ___________. The physician prescribed ampicillin 250 mg in 30 mL of D5/0. followed by a 15-mL flush.com 07/11/11 11:43 AM . _________ 21.314 UNIT 3 Dosage Calculations 19..” The safe dosage range is 0. The pump or controller should be set at ______ mL per hr. This child would receive _____ mg IV. for an 88-lb child. This is/is not within a safe range. the safe dosage range for this child is ____________. The safe dosage range is 0. The child’s weight is ____ kg. The physician prescribed Lasix 40 mg. IV. The label reads. IV.05 to 0. The child would receive _______ mL IV. ______ 20. The child’s weight is _____ kg. p. The physician prescribed morphine sulfate 5 mg.r. IV.2 mg/ kg/dose. Ampicillin requires 5 mL for reconstitution. The safe dosage range is 30 to 40 mg/kg/day. “Lasix.indd 314 www. q2h. q6h.n. The physician prescribed 300 mg of an antibiotic. ________ 22. for a 66-lb child. Morphine sulfate is available as 15 mg per 1 mL.ketabpezeshki. q6h. (021) 66485438 66485457 LWBK914-C14_p280-316.22% NSS to infuse over 30 min. This child would receive ______ mL. This is/is not within a safe range. 10 mg per mL. for pain for a child who weighs 88 lb. This is/is not within a safe range. The drop factor is 60 gtt per mL. The child’s weight is _____ kg. stat. A microdrip Soluset is used. (021) 66485438 66485457 LWBK914-C14_p280-316. The physician prescribed gentamicin 10 mg in 50 mL of D5/0. The IV is to infuse over 20 min via a microdrip Buretrol. followed by a 15-mL flush. A child is to receive an IV medication of 75 mg in 55 mL using NSS.45% NSS to infuse over 30 min via a Buretrol. You should set the rate at ______ mL per hr.ketabpezeshki. The medication is to be diluted in 60 mL of D5/¼ NSS and to infuse over 30 min. The nurse should set the pump at ______ mL per hr. The IV is to infuse over 45 min.com 07/11/11 11:43 AM . The drop factor is 60 gtt per mL. It is a microdrop tubing. 25. 24.CHAPTER 14 Pediatric Dosage Calculations 315 23. followed by a 15-mL flush. 27. The Buretrol is on a pump that should be set at ________ mL per hr. The nurse should set the controller at _____ mL per hr. followed by a 10-mL flush.indd 315 www. The nurse should set the pump at _____ mL per hr. Rocephin requires 10 mL for reconstitution. Gentamicin is available as 20 mg per 2 mL. A child is to receive Dilantin 25 mg per 2 mL in 10 mL using NSS. 26. followed by a 15-mL flush. The physician prescribed Rocephin 500 mg in 50 mL of NSS to infuse over 30 min via a Buretrol. A child is to receive 1 g of an antibiotic. followed by a 15-mL flush. The nurse should give _____ mL over 3 min. The flow rate should be set at _____ gtt per min to deliver 30 mL/hr. followed by a 10-mL flush. You would give _____ gtt per min with a total volume of _____ mL. 30. Give a child aminophylline 250 mg IVPB in 50 mL of NSS over 1 hr via a Buretrol that delivers 60 microdrops per mL.lww. 29. A child is to receive 30 mL of an intravenous solution every hour through a volume control set that delivers 60 microdrops per mL. (021) 66485438 66485457 LWBK914-C14_p280-316.indd 316 www. Aminophylline is available in 250 mg per 10 mL.ketabpezeshki.22% NSS solution every hour through a volume control set that delivers 60 microdrops per mL.316 UNIT 3 Dosage Calculations 28. SoluMedrol is labeled 40 mg per mL. The physician prescribed Solu-Medrol 20 mg by slow IV push for an asthmatic child.com/Boyer8e. 31. The flow rate should be set at _____ gtt per min to deliver 15 mL per hr.com 07/11/11 11:43 AM . An infant is to receive 15 mL of D5/0. Additional practice problems to enhance learning and facilitate chapter comprehension can be found on http://thePoint. soaks.g. you should be able to: • Apply the basic steps for reconstituting medications packaged as powders. Solutions can be administered externally (e. • Calculate the preparation of a topical or irrigating solution.g..ketabpezeshki. irrigations) or internally (e. compresses.indd 317 www..com 07/11/11 1:10 PM . nutritional formulas). • Calculate the reconstitution of an oral or enteral feeding.CHAPTER 15 Solutions and Drug Reconstitution LEARNING OBJECTIVES After completing this chapter. parenteral medications. solids. 317 (021) 66485438 66485457 LWBK914-C15_p317-336. or gases (known as solutes) that are dissolved in a diluent (known as a solvent). S olutions are mixtures of liquids. When setting up the ratio and proportion for a solution made from a pure drug or from a stock solution. the greaterr is the solution strength. always less than 100%. the weakerr is the solution strength. Remember: the less solvent added. Full-strength drugs are considered to be 100% pure. for example. use the strength of the desired solution to the strength of the available solution as one ratio. Solution problems are basically problems involving percents that can be solved using the ratio and proportion method. desired solution strength : available solution strength : : amount of solute : total amount of solution You can substitute the Formula Method when using a proportion for a solution made from a stock solution: Desired stre r ngth t × total amoun o t of solution Availabl a e stre r ngth t = amount of solute needed D ×Q = x H (021) 66485438 66485457 LWBK914-C15_p317-336. the more solvent added.indd 318 www. from which weaker solutions are made.318 UNIT 3 Dosage Calculations Solutions can be prepared from full-strength drugs or from stock solutions. Solution strengths can be expressed in a percentage or ratio format. a 1/2-strength solution means that there is one part solute to two parts total solution.com 07/11/11 1:10 PM . whereas stock solutions contain drugs in a given solution strength.ketabpezeshki. and the solute to the solution as the other ratio. The drug label.indd 319 www.com 07/11/11 1:10 PM .9% NS) for injection Sterile water for injection Reconstituted injectable medications are available in single-strength (either single. When the available amount of a drug is in a solute form (dry powder). package insert. Diluents for reconstitution must always be sterile when added to a dry powder. Sample diluents include: • • • • Bacteriostatic water Special packaged diluent Sodium chloride (0. Change solutions expressed in the fraction or colon format to a percent (1 : 2 or 1/2 is equal to 50%). it is important to remember two things: 1.CHAPTER 15 Solutions and Drug Reconstitution 319 When calculating solution problems. milligrams with milliliters. Remember: For multiple-strength solutions. the drug needs to be dissolved or reconstituted into a liquid form by adding a liquid diluent (solvent).ketabpezeshki. grains with minims). Work within the same measurement system (e. Although a pharmacist usually prepares the drug. or reference material will list the manufacturer’s directions for reconstitution (adding the diluent and mixing thoroughly). 2.or multiple-dose vials) or multiple-strength solutions. for example. so they are packaged as a powder. Reconstitution: Preparing Injections Packaged as Powders Some medications are unstable in a liquid solution. 75 mL (021) 66485438 66485457 LWBK914-C15_p317-336.. the dosage strength depends on the amount of diluent.g. a nurse may have to do so in some settings. 000 units per mL. • Note the length of time the medication will remain stable after reconstitution. Reconstituted solutions will always exceed the volume of the added diluent. This added volume will determine the medication concentration (available dose). preparation requirements (e.indd 320 www.g. • Use one of the three standard methods to calculate dosages. Follow these steps: • Read the label for reconstitution directions. and storage requirements (e. temperature. • Selectt the type and quantity of recommended diluent. • Determine the number of doses available in a multidose vial.000 units per mL. whereas 30 mL of diluent may yield 500. • Note the total fluid volume..g. Note: Some preparations allow for different quantities of diluent. expiration..com 07/11/11 1:10 PM . which result in different solution strengths. Basic Steps for Reconstitution Remember: Always read the package insert or labeled directions for reconstitution very carefully because directions will vary for different medications. • Labell the medication with the date and time of preparation. shake well). • Initiall labeled vials. (021) 66485438 66485457 LWBK914-C15_p317-336.320 UNIT 3 Dosage Calculations of diluent may yield a solution of 200. and reconstituted dosage if using a multiple-dose vial.ketabpezeshki. protection from light). What you have available is the strength of the drug after reconstitution. and withdraw prescribed dissolved fluid amount.CHAPTER 15 Solutions and Drug Reconstitution 321 Note: What you desire is what the physician ordered. R U L E To prepare a reconstituted medication: Follow the reconstitution directions (see previous steps). Ratio and Proportion 225 mg : 1 mL = 250 mg : x mL 225x = 250 50 x= 250 50 = = 1. IM.1 mL (021) 66485438 66485457 LWBK914-C15_p317-336. Store at room temperature for 24 hr. Solution concentration will equal 225 mg per mL. Total approximate available volume is 2. dilute powder.com 07/11/11 1:10 PM .indd 321 www. RECONSTITUTE: Labeled directions: Reconstitute by adding 2 mL of sterile water as a diluent. EXAMPLE #1: G Give 250 mg of Ancef. every 8 hr.2 mL.ketabpezeshki. The medication is available as a powder in a 500-mg vial.1 mL 225 45 45 ANSWER: 1. Shake well until dissolved. IM. RECONSTITUTE: Labeled directions: Reconstitute by add- ing 8 mL of sterile water for injection. Total approximate available volume will be equal to or greater than 8 mL. Solution concentration will equal 62. (021) 66485438 66485457 LWBK914-C15_p317-336.1 mL 225 45 45 ANSWER: 1.5 mg per mL. Medication is available as a powder in a 500-mg vial.1 mL 225 45 45 ANSWER: 1.322 UNIT 3 Dosage Calculations The Formula Method D ×Q = x H 250 mg ×1 mL 225 mg 50 250 50 = = 1.ketabpezeshki.1 mL EXAMPLE #2: G Give 125 mg of Solu-Medrol.1 mL Dimensional Analysis 250 mg = × 1 mL 225 mg 250 mg × 1 mL 250 ×1 (mL) = 225 mg 225 50 = 250 50 = = 1.com 07/11/11 1:10 PM .indd 322 www. 5 mg 62.indd 323 www.5 1 ANSWER: 2 mL Dimensional Analysis 125 mg = × 1 mL 62.5x = 125 2 x= 125 = 2 mL 62.com 07/11/11 1:10 PM .ketabpezeshki.5 2 125 = 2 1 mL = 2 mL 62.CHAPTER 15 Solutions and Drug Reconstitution 323 Ratio and Proportion 62.5 2 = 125 = 2 mL 62.5 1 ANSWER: 2 mL (021) 66485438 66485457 LWBK914-C15_p317-336.5 mg 125 mg × 1 mL 125 ×1 (mL) = 62.5 mg : 1 mL : : 125 mg : x mL 62.5 1 ANSWER: 2 mL The Formula Method D ×Q = x H 125 ×1 mL 62. and LeMone. Sometimes the feeding solution needs to be prepared from a powder or diluted with sterile water or tap water.indd 324 www. commercially prepared. Feedings. a tube can be placed in the stomach or duodenum (nasogastric tube) or inserted into the stomach (gastrostomy tube. R U L E To prepare a specific strength solution from a given solution: Multiply the desired strength by the amount of solution (solute) and then subtract the solute from the total amount of solution (amount to be given)..e.com 07/11/11 1:10 PM ..1 Enteral feeding pump. PEG tube).]. C. a Kangaroo pump). FIGURE 15.1.) (021) 66485438 66485457 LWBK914-C15_p317-336.. Refer to a nursing fundamentals textbook for review of the standard procedures for enteral feedings. [2008]. (From Taylor.ketabpezeshki. C. Fundamentals of nursing: The art and science of nursing care [6th ed. Philadelphia: Lippincott Williams & Wilkins. P. are given as a bolus or via a feeding pump either intermittently or continuously (i. page 1471. Lillis.324 UNIT 3 Dosage Calculations Preparing an Oral or Enteral Feeding When a person cannot eat. See Figure 15. Set the feeding pump to 50 mL per hr. EXAMPLE #2: G Give 1/2-strength Ensure 16 oz via a naso- gastric tube q12h. MULTIPLY: 1//3 × 300 mL = 100 mL (solute) SUBTRACT: 3000 mL – 100 mL = 200 mL (solvent to be dissolved). Flush tube with 50 mL. Set pump to 40 mL per hr.com 07/11/11 1:10 PM .ketabpezeshki. Monitor patient tolerance ANSWER: Give 300 mL over 6 hr. Sustacal is available in a 10-oz can (10 oz × 30 mL/oz = 300 mL). FLUSH: Fllush tube with 50 mL.CHAPTER 15 Solutions and Drug Reconstitution 325 EXAMPLE #1: G Give 1/3-strength Sustacal every 6 hr through an NG tube. (021) 66485438 66485457 LWBK914-C15_p317-336.indd 325 www. ADD: 2000 mL of water to 100 mL of Sustacal = 300 mL at 1/3 strength GIVE: 3000 mL over 6 hr. CONVERT: 166 oz = 480 mL (16 oz × 30 mL/oz) MULTIPLY: 1//2 × 480 mL = 240 mL (solute) SUBTRACT: 4880 mL – 240 mL (solvent to be dissolved) ADD: 2440 mL of water + 240 mL Ensure = 480 mL of 1/2-strength Ensure ANSWER: Give 480 mL over 12 hr. Set the feeding pump to 50 mL per hr. The Formula Method D ×Q = x H 1 10% 10 1 = = 100% 100 10 10 1 ×1. measure 100 mL of pure drug and add 900 mL of water to prepare 1.0 L of a 10% solution.326 UNIT 3 Dosage Calculations Preparing a Topical Irrigating Solution Preparing a Solution from a Solution EXAMPLE #1: Prrepare 1. EXAMPLE #2: Prrepare 250 mL of a 5% solution from a 50% solution. Measure 25 mL of solute and add 225 mL of water to prepare 250 mL. (021) 66485438 66485457 LWBK914-C15_p317-336.indd 326 www. 000 mL = 100 mL 10 ANSWER: 100 mL.ketabpezeshki. The Formula Method D ×Q = x H 5% 5 × 250 mL 50 % 1 = 25 mL of solute needed ANSWER: The solution has a ratio strength of 1 : 10.com 07/11/11 1:10 PM .0 liter (L) of a 10% solution from a pure drug. ketabpezeshki. Solution concentration will provide 270 mg per mL. Add ______ mL of water to make 500 mL. Fluid volume will equal 7. 2. 327 (021) 66485438 66485457 LWBK914-C15_p317-336. you would need ______ mL of solute.0 mL of sterile water for injection and shake well.5 L. The physician prescribed 500 mg of Cefizox. Give _____ mL every 12 hr. To make a 30% solution. Use approximate quantities for dosage calculations. for a genitourinary infection. you would need ______ g of solute. The medication is available as a powder in a 2-g vial.com 07/11/11 1:10 PM . Add ______ mL of water to make 1.End of Chapter Review Complete the following problems: To prepare 400 mL of a 2% sodium bicarbonate solution from pure drug. you would need ______ mL of solute. IM. Reconstitute it with 6.4 mL. There is 500 mL of 40% magnesium sulfate solution available for a soak. To make 1. every 12 hr.5 L of a 5% solution from a 25% solution.indd 327 www. 3. 4. (021) 66485438 66485457 LWBK914-C15_p317-336. The physician prescribed 125 mg of SoluMedrol. for severe inflammation.com 07/11/11 1:10 PM . The nurse would then give _____ mL to give 125 mg.indd 328 www.5 g.7 mL of sterile water for injection and shake well. the nurse should give _____ mL. 6. Reconstitute it according to directions so that each 8 mL will contain 0.5-g vial. Directions state to reconstitute it with 5. Four grams of the medication is available as a powder in a vial.328 UNIT 3 Dosage Calculations 5.5 g. Methicillin sodium 1. To give 1. The medication is available as a powder in a 0. IM. IM.ketabpezeshki. was prescribed for a systemic infection.5 g of Solu-Medrol. Solution concentration will provide 500 mg per mL. indd 329 www. The drug is available as 25 mg per tsp. Give ______ mg. Critical Thinking Check Would it seem logical to give a tablespoon of medication to give 75 mg? _______ Yes or No? 6. 329 (021) 66485438 66485457 LWBK914-C15_p317-336. Give 0. The drug is available in 250-mg tablets. Give 600 mg. 5. Give 125 mg. Give ______ tablet(s). Give 2 tsp. 2.End of Unit 3 Review Solve the following drug administration problems and reduce each answer to its lowest terms.com 07/11/11 1:10 PM . The drug is available as 150 mg per 2. The drug is available in 200-mg tablets. 1.ketabpezeshki. Give 75 mg. Give ______ tablet(s). Give ______ mL. Give ______ mL.25-g tablets. 4. 3.5 mL. Give ______ tablet(s).5 g.3 g. Give 1. The drug is available as 250 mg per 5 mL. The drug is available in 0. 5 mL of solution contains 250 mg of the medication.5 mL of sterile water for injection. 11. Give 0. The drug is available as 300 mg per 2 mL. Give ______ mL. Give 500 mg of a medication that is available as a powder in a 2-g vial. The drug is available as 8 mg per mL.330 UNIT 3 Dosage Calculations 7. Give gr 1/6. The drug is available as 60 mg per mL. Give ______ mL.indd 330 www. The drug is available as 500 mcg per 2 mL. Reconstitute it by adding 11.3 mg. 14.25 g. 15. Give ______ mL. 12. (021) 66485438 66485457 LWBK914-C15_p317-336.75 mg. Give ______ mL.com 07/11/11 1:10 PM .6-mg tablets. 9. 10. 16. Give ______ tablet(s). 13. Each 1. Give 80 mg of a drug that is available as 240 mg per 3 mL. Give ______ mL. Give 0.ketabpezeshki. Give gr 1/100. Give gr 1/8. The drug is available as 15 mg per mL. Give 50 mg. Give ______ mL. The drug is available as 100 mg per 2 mL. 8. Give ______ mL. The drug is available as 200 mcg per mL. Give gr iii. Give ______ mL. The drug is available in 0. Give ______ mL. Give 0. CHAPTER 15 Solutions and Drug Reconstitution 331 17. 19.ketabpezeshki. Give 250 mg of a solution in 500 mL at 10 mL per hr.000 mL of a solution over 6 hr. using a drop factor of 10 gtt per mL. 23. would you expect the gtt per min to be greater or less than the gtt per min for a drop factor of 10? ______ Greater or Less than? 20.000 mL of a solution over 8 hr. 18. Give ______ mg per hr. Give 500 mL of a solution over 10 hr. You would give ______ mL per hr. Critical Thinking Check If the available tubing had a drop factor of 15 gtt per mL. using a drop factor of 10 gtt per mL. Reconstitute it by adding 5 mL to achieve a concentration of 330 mg per mL. Give ______ mL.indd 331 www. using a drop factor of 60 gtt per mL. Give over ______ hours and ______ minutes. Give 800 mL of a solution at 12 gtt per min. Give ______ gtt per min. Give 125 mg of a drug dissolved in 100 mL of a solution over 30 min. 22. Give 1. Give 1. Give ______ gtt per min.com 07/11/11 1:10 PM . using a drop factor of 15 gtt per mL. 21. Give ______ gtt per min. Give 1 g of a medication that is available as a powder in a 2-g vial. (021) 66485438 66485457 LWBK914-C15_p317-336. followed by ______ units of ______. Give 2. Draw up ______ units of ______ first. Is this a safe dose? Yes ______ or No ______ (021) 66485438 66485457 LWBK914-C15_p317-336.000 mL of D5W with 40.5 mg/kg/dose. The safe dosage range is 1 to 1. IV. IV/IM.ketabpezeshki. Give ______ units per hr. Give 15 units of U-100 Regular insulin by subcutaneous injection.000 units per mL. The safe dosage range is 0.com 07/11/11 1:10 PM .25 to 0. An ER physician ordered 30 mg of a drug. 27. Vial concentration is 5. The nurse would give ______ mL. stat. Give 1. as needed for pain for a 44-lb child. Draw up insulin in the syringe to the ______ -unit marking. Give ______ units per hr. IV. Give ______ mL. Use U-100 Regular insulin and a U-100 syringe. Is this a safe dose? Yes _____ or No _____ 30. The safe dosage range for this child is ______ mg/dose. using U-100 insulin and U-100 syringes. The drug is available as 100 mg per 2 mL. q4h. 26. 25.500 units of heparin subcutaneously.indd 332 www. Give 35 units of NPH and 10 units of Regular insulin. 28. Give 1. for a 154-lb teenager who had a tibia fracture.332 UNIT 3 Dosage Calculations 24. ______ 29. A physician prescribed 25 mg of a narcotic.000 mL of D5W with 15.000 units of heparin to infuse at 30 mL per hr.5 mg/kg/dose. which is or is not a safe dose.000 units of heparin to infuse at 25 mL per hr. The safe dosage is 40 mg/ kg/day. Solu-Medrol is available as 40 mg per mL.4 g. The physician prescribed gentamicin 15 mg. q8h. The safe dosage range is 0. The physician prescribed 1 mg. IM. The physician prescribed a narcotic 6 mg.1 to 0. A physician ordered Solu-Medrol 30 mg. The nurse would give _____ mg q8h. for a 6.5 mg/kg/day.5-kg infant. as needed for pain for a 110-lb child.com 07/11/11 1:10 PM . q8h.indd 333 www.2 mg/kg/dose. The dosage range for this child is ______ mg per day. q12h. Gentamicin is labeled 10 mg per mL for IV use. Morphine is available as 15 mg per mL. IV. Is this a safe dose? Yes ______ or No ______ 33. The safe dosage range is 6 to 7. Is this a safe dose? Yes ______ or No ______ 35. The safe dosage range for this infant is ______ mg /day. of leucovorin calcium. The safe dosage range is 0. The physician prescribed vancomycin 0. The nurse would give ______ mL. The nurse would give ______ mL. for an 88-lb child. IV. to be given once a day for the treatment of megaloblastic anemia.7 mg/kg/day. IV. The safe dosage range for this child is ______ mg/ dose.ketabpezeshki. The nurse would give ______ mL. Is this a safe dose? Yes ______ or No ______ 32. q3h. for a 66-lb child. Is this a safe dose? Yes ______ or No ______ 34.CHAPTER 15 Solutions and Drug Reconstitution 333 31.5 to 1. The medication is available as a powder in a 50-mg (021) 66485438 66485457 LWBK914-C15_p317-336. The safe dosage range for this child is ______ mg/day. IV. (021) 66485438 66485457 LWBK914-C15_p317-336. The physician prescribed 25 mg of Librium.0 mL of bacteriostatic water for injection. for a patient with a severe infection.indd 334 www. The physician prescribed Timentin 3. Solution concentration will yield 10 mg per mL. Answer the next three questions by referring to the corresponding drug labels.UNIT 3 334 Dosage Calculations vial. IV. Reconstitute it with 5. 36. (Courtesy of GlaxoSmithKline.ketabpezeshki. Shake it well. The nurse should give ______ mL.0 mL.1 g. The patient would receive ______ g of Timentin in 24 hr.com 07/11/11 1:10 PM . every 6 hr. Timentin. once a day. Give ______ mL. PA. Philadelphia. IM. Fluid volume will equal 5.) 37. Add 2 mL of special diluent to yield 100 mg per 2 mL. Requip. The physician prescribed Avandia 8 mg twice a day. The patient would receive ______ mg in 24 hr. PA.CHAPTER 15 Solutions and Drug Reconstitution 335 Avandia. Philadelphia. PA. Philadelphia. In order to control a patient’s blood glucose.) 39. Insulin 100 units in 100 mL is started at 6 mL per hr. three times a day.com 07/11/11 1:10 PM .) 38. A patient with Parkinson’s disease is to receive Requip. 3 mg.ketabpezeshki. You document that the patient is receiving ______ units/hr. 40. The nurse would administer ______ tablet(s) each dose for a total of ______ mg in 24 hr. an insulin infusion is prescribed. (Courtesy of GlaxoSmithKline. (Courtesy of GlaxoSmithKline.indd 335 www. (021) 66485438 66485457 LWBK914-C15_p317-336. immediately. The nurse would reconstitute the vial of Ancef with __________ mL of sterile water for injection. Answer the next two questions by referring to the corresponding drug label. Ancef. (021) 66485438 66485457 LWBK914-C15_p317-336. (Courtesy of GlaxoSmithKline.indd 336 www.com/Boyer8e.com 07/11/11 1:10 PM . Additional practice problems to enhance learning and facilitate chapter comprehension can be found on http://thePoint.ketabpezeshki. The nurse would need to mix ___________ vial(s) for each dose. intramuscularly.336 UNIT 3 Dosage Calculations 41. every 8 hr.) 42. PA. Versed 50 mg in 100 mL is running at 3 mL per hr to manage anxiety in a mechanically ventilated patient. A patient is prescribed 500 mg of Ancef intramuscularly. 43. A physician prescribed 1 g of Ancef.lww. Philadelphia. You document that the patient is receiving ______ mg per hr. Answers (021) 66485438 66485457 LWBK914-ANS_p337-360.indd 337 www.com 07/11/11 1:53 PM .ketabpezeshki. 72 48. 5.75 1. 42. 50. 183% www. 4/5 3/4 16 0. 23. 1/150 17.indd 338 2. 0.87 44. 52. 34. 4 1/18 33. 31. 7% 68.33 0. 47. 10. 36% 67. 10. 1/100 20. 35. 21.5% (021) 66485438 66485457 LWBK914-ANS_p337-360. 28. 49. 53. 38.2 20% 12. 39. 3/4 24. 56.81 2. 7. 60. 0.4 1/4 9/20 3 10 24 0. 19. 94/9 32. 0. 62. 27. xiii Li 16 19 1/2 3. 15. 14.78 3. 6.3% 1/3 3/5 2. viii xxxvii 15 9 5/8 4/15 1/3 3/4 3/8 6 1/8 1/48 14/5 57/7 3 1 3/13 0. 25.16 64.37 40. 46.250 45. 51.75 0. 65 13. 3 3/7 8 2/5 1/60 2/5 27/4 29. 9. 66.com 07/11/11 1:53 PM .ketabpezeshki. 55. x 8. 57. 54. 30.13 48. 63.9 65. 58. 1/2 16.6 12 0. 4 41. 18. 61. 43. 3 2/11 36. 11. 12.40 37. 4. 59. 26.338 Answers CHAPTER 1: Preassessment Test: Mathematics Skills Review Basic Math Pretest: Pages 4–8 1. 5. 22. 82.Answers 69. 50 Percent Colon Ratio Common Fractions Decimal 93. 4 Practice Problems: Page 14 1. 96.2% 0.0067 0. 80.25 0. 72. 1/4. 71. 89. 97. 1/3 (021) 66485438 66485457 LWBK914-ANS_p337-360. 8 3.05 0.ketabpezeshki. 1/150.3% 5% 0. 1/25. 60% 1. 100. 92. 10 4.2% 0.indd 339 www. 5 2. 1/5. 1/8 5.000 1 : 100 1 : 120 50 : 100 1/4 1/30 1/20 1/150 9/2. 76. 1/7. 87. 4/5 2. 73.0083 0. 98. 7.0175 18 40 20% 120 70.01 0.50 25% 3. 1/12. 3. 1/10.25 0.4 0. 81.com 07/11/11 1:53 PM . 77. 8/15 Order of size: smaller to larger value 1/300.83% 50% CHAPTER 2: Fractions Practice Problems: Page 12 1. 90.8 0. 1. 99.0045 0. 1/9 6. 4/6 3. 75.15 0. 95. 25 : 100 1 : 30 5 : 100 1 : 150 9 : 2. 25% 91.08 88.083 9 25 25% 339 1% 14.033 0.000 1/100 1/120 1/2 0. 1/9. 1/75. 74. 94.048 0. 25% 198% 0. 84. 9. 7. 1/2 4. 83. 1/8.0036 85.45% 1% 0.67% 0. 78. 4. 86. 1/100. 79. 4. 10. 2 2/3 9. 7 5/9 6. 16/45 1 7/20 6 3/4 36 2. 10. 27/5 Practice Problems: Pages 25–26 1. 14. 7 3/4 7 1/2 6 6/11 4 3/10 18 2/3 3. 13. 2. 87/4 9. 9. 4. 6. 6. 8. 13/16 1 3/10 10 23/45 3/7 19/36 3. 43/5 6. 4. (021) 66485438 66485457 LWBK914-ANS_p337-360.indd 340 5/21 21/32 1 2/13 29/50 www. 9. 98/3 8. 3/5 8.com 07/11/11 1:53 PM . 1/6 7. 7. 1/9 6. 1/4 Practice Problems: Page 20 1. 7. 16. 1/6 4. 7. 3 19/24 1 9/19 1 5/8 4/9 5 16/21 3. 6 5/6 5. 1/6 12/20 5/8 1/6 1/18 3. 1/6 5. 57/9 69/12 136/9 37/2 67/6 3. 11. 10. 15. 3/20 40/77 1 5/9 3 5/7 Practice Problems: Pages 42–43 1. 7. 1/4 Practice Problems: Page 24 1. 55/8 5.340 Answers Practice Problems: Pages 18–19 1. 10. 2. 8. 20/40 5. 1/9 8. 5. 9 5/9 Practice Problems: Pages 36–37 1. 4. 1/3 2. 12. 12. 4. 7. 4.ketabpezeshki. 10. 2. 5. 6/10 9. 11. 7 1/2 8. 3/5 3. 2/4 6. 2 5/11 1 2/45 1 3/14 1 17/30 13/30 1 1/12 2. 1/8 7. 15. 8.92 3. 27. 0. ten and one thousandths three and seven ten-thousandths eighty-three thousandths one hundred and fifty-three thousandths thirty-six and sixty-seven ten-thousandths one hundred and twenty-five ten-thousandths one hundred twenty-five and twenty-five thousandths twenty and seventy-five thousandths 10. 2. 0.037 13. 14 28. 10 31. 6 1/2 209/23 1/9 1 1/3 1/6 4 9/40 3/20 8 1 5/7 5/56 3.064 14. 64.020 5. 4. 14.75 4. 5.015 Practice Problems: Page 52 1. 3. 14/35.7 0.indd 341 2.1 0. 29. 1/6 6. 11/24 25. 1. 1/8 13. 24. 9. 50/11 10. 8. 20.com 07/11/11 1:53 PM . 7/12 22. 10 4/15 34. 33. 12. 4/20 5. 23. 12. 26. 15/35 4. 2. 17. 21. 9. 18.75 www. 0. 30.80 (021) 66485438 66485457 LWBK914-ANS_p337-360. 15. 8/9 16. 33. 13 1/8 5/16 5/28 31/36 5/9 2 1/8 3/11 6/11 24 80 CHAPTER 3: Decimals Practice Problems: Pages 50–51 1. 8. 28/20. 7. 4 1/2 2. 6.ketabpezeshki.4 16.07 11. 11. 7 5/24 19. 0. 32.Answers 341 End of Chapter Review: Pages 44–46 1. 7. 26. 7.68 22.001 2.067 7/1.91 51.128 16.47 981.85 2. 59. 10. 5.77 21.000 5 3/100 2. 224. 8. 15.125 0.20 0. 19. 16. 4. 84. 0.51 1065 144. 9.14 0.3 6. 13. 27.64 26. 35.67 0. 12.41 19.58 6.4 3/50 33. 10.053 103/250 1/8 7.25 0. 0. 5.143 3/4 0.6 0.75 30. 11.03 30.776 0. 8. 22.2 1.33 27.56 18. 26. 6.21 15. 11. 18. 14.65 3.com 07/11/11 1:53 PM .12 101.342 Answers Practice Problems: Pages* 59–61 1. 17.9 400. 38. 17. 34. five and four hundredths ten and sixty-five hundredths eight thousandths eighteen and nineteenths 6. 3. 20. 4. 28. 18.81 41. 4.067 93/100 12 1/5 End of Chapter Review: Pages* 66–68 1. (021) 66485438 66485457 LWBK914-ANS_p337-360. 20. 21. 29.08 9.0008 10. 24.387.ketabpezeshki. 23.2 8. 6.8 8 1/2 * See Appendix B: Answers have been rounded off. 13. 31.262 24. 0. 19. 25. 16.25 6.89 0.35 1. 11.098 2.45 12. 0.52 5.94 708. 16.54 9.89 3. 9/20 0. 25. 8.58 24. 5. 12.15 12. 4. 10. 2.91 243. 0. 6 4/5 0.22 1 7/20 Practice Problems: Pages* 64–65 1.32 12. 28.26 6. 9. 0. 22.33 1.indd 342 www. 5.06 66.4 7. 14. 32.77 3. 23. 124. Ratio. 325 mg : 1 tab. 11. 9. and Proportion Practice Problems: Page 74 1. 50 mg/5 mL 5 mL 325 mg . 0.80 8.ketabpezeshki.com 07/11/11 1:53 PM . 8. 1L 4. x = 18 (021) 66485438 66485457 LWBK914-ANS_p337-360. 325 mg/1 tab 2.25 6. 60% 1/8 = 12. 4.3% Practice Problems: Pages 88–89 1. = 5 mL 15 mL 10 mg : 5 mL = 30 mg : 15 mL 8. 0. 250 mg : 1 capsule. 3/20 3/4 33 1/3% 75% 2. 2 ampules/1 L 3. 2 ampules : 1 L. 85% 1/5 = 20% 12. 3. 1 tabl a et 2 ampul m es . 5. 6.Answers 343 CHAPTER 4: Percents.6% 40% 3. 25% 9. 50 mg : 5 mL. 250 mg . 2. 0 2 mg = 0 4 mg 1 tabl a et 2 tabl a ets 0.59 45% 1/6 = 16. 50 mg .15 5. 7. x = 9 9.indd 343 www. 10.2 mg : 1 tablet :: 0. 0. 12. 1 tabl = 5 grai r ns 15 grai r ns 1 tablet : 5 grains :: 3 tablets : 15 grains 6. 3/10 1/4 66. 7.5% 11. 1/2 3/5 20% 25% Practice Problems: Page 78 1.6% 1/3 = 33. 250 mg/capsule 1 capsule a et 3 tabl a ets 5. 0. 10. 4.4 mg : 2 tablets 10 mg 30 mg 7. 344 Answers 10.indd 344 www.40 1.25 mg 15. 6. 1 g/5 mL = x g/15 mL 5x = 15 x=3g End of Chapter Review: Pages 90–94 1.052 4. 12. 9.com 07/11/11 1:53 PM . 15. x = 50 12.21 0. 7.4% 21% 40% 162% 27% 5 1/4% 450% 8 1/3% 1% 85. 4.8 mL 13. Percent Fraction Decimal 16. 13.6% 25% 6. 125 m g x 14.7% 450% 150% 72% 1/6 1/4 8/125 21/100 2/5 1 31/50 27/100 21/400 9/2 1/12 1/100 6/7 18/4 1 1/2 18/25 0.72 (021) 66485438 66485457 LWBK914-ANS_p337-360. 10. 5.083 0. 14.01 0.125 × 2 x = 0.5 0. 25 mg = x mg 1 1. 50 mg = 40 1 mL x mL 50x 0 = 40 x = 0. 3. 8. = 1 tabl a et 2 tabl a ets x = 0.62 0.50 0.5 x = 37.25 0. x = 4 11.166 0. 11.5 mg 0 .064 0.27 0.5 mL x = 25 × 1.857 4.5 1.ketabpezeshki. 2. 1 kg 19. 0. 26.5 mL :: 500 mg : x mL 23. 10 mg : 1 tab 1 tabl a et 10 units .8 5 24. 250 mg = 500 mg 0 5 mL x mL 250 mg : 0. 25.5 x=6 20 mg : 1 mL :: 10 mg : x mL 20 mg × x mL = 10 mg × 1 mL 20x 0 = 10 1 1 20 x 10 1 = = mL 20 1 20 2 2 ANSWER: (021) 66485438 66485457 LWBK914-ANS_p337-360. 100 mg = 300 mg 1 tabl a et x tabl a ets 100 mg : 1 tablet :: 300 mg : x tablets 20. 4 or 0. 6 4.com 07/11/11 1:53 PM . 200 mg : kg 18. 10 mg .075 mg : 1 tablet :: 0.ketabpezeshki. 10 units : 1 mL 17.indd 345 1 mL 2 www. 250 mg = 500 mg 1 tabl a et x tabl a ets 250 mg : 1 tablet :: 500 mg : x tablets 075 mg 0 15 mg 21.075 = 1 tabl a et x tabl a ets 0.Answers 345 16. 27. 1 mL 200 mg .15 mg : x tablet 22. 346 Answers Verify the Answer: EXTREMES E 1 20 mg : 1 mL : : 10 mg : (0.5 mL Verify the Answer: 50 mg 25 mg = 5 mL 2 5 mL 50 × 2.ketabpezeshki.5) mL 2 MEANS M 20 mg × 0.5 = 125⎪⎫⎪ Sum produc r ts ⎬ 25 × 5 = 125 ⎪⎪⎭ are r equa u l CTC = Yes *CTC = Critical Thinking Check (021) 66485438 66485457 LWBK914-ANS_p337-360.5 mL = 10 mg × 1 mL 20 × 0.5 = 10⎫⎪⎪ Sum pro r ducts ⎬ 10 ×11 10 ⎪⎪⎭ are r equall CTC* = Yes 28.indd 346 www. 50 mg 25 mg = 5 mL x mL Cross-multiply: 50 mg × x mL = 25 mg × 5 mL 50x 0 = 125 1 5 50 x 125 = 50 1 50 2 x= 5 1 = 2 mL 2 2 ANSWER: 2.com 07/11/11 1:53 PM . Answers 347 ANSWER: 1 mL 2 29.5 = 50⎪⎫⎪ Sum produc r ts ⎬ 25 × 2 50 ⎪⎪⎭ are r equall CTC = Yes (021) 66485438 66485457 LWBK914-ANS_p337-360.5 mL = 25 mg × 2 mL 20 × 2.indd 347 www.0 mg × 0.5 mg × 1.0 mg × x mL = 1.com 07/11/11 1:53 PM . 3.0 mL :: 1.5 mL = 1.0 mL 3x = 1.0 mg : 1.5 mL MEANS M 3.5 mg : x mL 3.5 mg × 1.0 mL : : 1.5 mL Verify the Answer: 20 mg : 2 mL = 25 mg : 2.5 mg : 0.0 mg : 1.0 mL 3 0 × 0 5 = 1 5⎪⎫⎪ Sum produc r ts ⎬ 1 5 ×1 0 = 1 5 ⎪⎪⎭ are re equal CTC = Yes 30. 20 mg : 2 mL : : 25 mg : x mL 20 mg × x mL = 25 mg × 2 mL 20x 0 = 50 1 5 20 50 5 = = = 2 5 mL 1 2 2 20 20 ANSWER: 2.ketabpezeshki.5 mL 20 mg × 2.5 1 1 3 x 15 1 = = 31 32 2 x= 1 mL 2 Verify the Answer: EXTREMES E 3. 34. 35. 19.5 mL 7. 13. 15.com 07/11/11 1:53 PM .4 22. 27.5 mL 0. 41. 7. 38. 7.67 26.26 3. 40.348 Answers 31. 31.25 0. 3.5 = 30) 1 1/4 (8 × 1.1 20. 11. 1/6 1/3 16.5 mL 1. 5/30 1/100 18. 29. 5. 1/16 4/15 8.2 & 20 × 1. 1/15 1 4. 21. 1. 1/2 0. 1/150 1/75 10.8 28. 5. 32.5 (100 × 1/2 & 2 × 2. 33. 15 2.000 × 1/4 = 250) 0.33 30. 4. 1/300 1/4 34. 1 1/2 7/100 32.5 mL 1. 37.68 0.2 & 1 × 10 = 10) 1 3/5 (4/5 × 50 & 25 × 1. 9.6 = 40) 1/2 (500 × 1/2 & 1. 5/12 7/10 6. 3 1/3 1/4 14. 35.indd 348 www. 37.ketabpezeshki.89 16. 39. 0.6 mL 0. 36. 4/5 2 12. 2. 33. 42. 40% 3/500 36. 17.7 mL 3 tablets End of Unit 1 Review: Pages 95–97 1. 23. 2% 450% 12 (4 × 12 & 3 × 16 = 48) 1 1/5 (25 × 1. 25.5 = 50) (021) 66485438 66485457 LWBK914-ANS_p337-360.5 24. 036 m 0.com 07/11/11 1:53 PM . 0. 8.ketabpezeshki.6 dm 0. 7.08 cm 2.500 mL 80 mg (021) 66485438 66485457 LWBK914-ANS_p337-360. 18. 16.047 L 569 mL 30 cg 930 mg 2. 17. 0.87 1 44. 9. 14.00743 m 10. 55.1 mg 0. 9. 11.217 mm 0. 4. 180 1/9 1 3/5 3 1/3 1 1. 12. 18.Answers 43. 46.200 mg End of Chapter Review: Pages 118–120 1. 50. 6.006 dm 6.000 cL 0. 53.0416 L 2.0036 L 900 mL 1.0164 dL 1. 17. 51.600 mL 3. 52. 10. and Apothecary Systems of Measurement Practice Problems: Pages 113–114 1. 15. 7.7 mL 64 mg 0. 47. 16.0356 g 50 mg 0. 12. 3. 3.indd 349 2. 45. 48.05 cm 3. 20. 13. 15. 19. 14.000 m 0.000 g 13. 5.000 mm 60 mm 0. 21. 41.001 mg 4.002 m 180 mm 0. Household. 349 2 600 5 90 1/4 2 CHAPTER 5: The Metric. 49. 4.000 g 600 mcg 10 mcg www. 6. 20.008 dg 1.0 g 800 cg 0.000 mcg 7. 0. 5. 19. 22. 54. 10. 13.02 m 1m 61. 8. 11.000 mcg 2. 5 L gr iii gr v mxxss 2 gal 1 oz 2 qt 4 drams 24 oz 120 gtt 16 oz 10. 43. 30. Answers 24.0003 L 10 mL 1. 6. 3. 34.0005 L 0.35 g 30. 14. 12. 30 gr 4 inches 300 to 325 mg 1/150 gr www. 50.0034 g 0. 56.06 g 0.350 23.04 mg 1. 26.500 mL 1 oz 45 gr 1 kg 3. 9. 58.com 07/11/11 1:53 PM . 11. 44. 38.indd 350 2. 13. 41. 360 mL 0. 5. 25 kg 960 mL per day 2 tsp 3 gtt (021) 66485438 66485457 LWBK914-ANS_p337-360. 17. 32.000 mcg 2.75 gr 0. 39. 16. 40. 4. 0.3 mg 1/10 gr 2L 2. 28.000 g drams v mx pt v ½ oz 2g ¼ pt 2 teacups 3 oz 9 tsp ½ pt CHAPTER 6: Approximate Equivalents and System Conversions Practice Problems: Pages 125–126 1. 60. 31. 51. 33. 35. 7.000 mL 0. 29. 7. 5. 8. 46.000 g 450. 8. 25. 57. 15.500 mcg 1 dg 0. 36. 55.000 mg 80 dL 460 dg 0. 52. 18. 47.3 mg 0. 53. 37. 0. 6. 54. 45. 59.000 cL 500 mg 25.ketabpezeshki. 27. 49. 4. 48. 2 tbsp 66 lb 2g 60 mL 1 qt 15 mL End of Chapter Review: Pages 127–129 1.13 g 18. 10. 42. 500 mg 1/4 gr 2. 18. (021) 66485438 66485457 LWBK914-ANS_p337-360. 10. 20. Shake well before using. 6. 19. 80 mg 1. 30. 25.6 mg End of Unit 2 Review: Pages 130–131 1. 11.4 g 450 mL 1 tbsp 10. 16. Add 2/3 of total water for reconstitution. 8. 180 mg 2 ounces 1 tsp 250 mg. Each 5 mL contains amoxicillin 200 mg.com 07/11/11 1:53 PM . 0. 9. 27.2 (Augmentin) 1.ketabpezeshki.indd 351 www. 200 mg per 5 mL 3.000 mcg CHAPTER 7: Medication Labels Practice Problems: Pages 141–143 FIGURE 7. 12. 19. 14. 16. Keep tightly closed. 5. 1 g 2 tsp 2 tablets. 351 18 kg. 3. 15. Amoxicillin/clavulanate potassium 2. 4. 24. 1-ounce 1.95 g 6. 13.4 mg 54 mL 8.005 g 30 gtt 16 ounces 1 ounce 1 ounce 1 ounce 1 ounce 60 to 65 mg 44 lb 1/200 gr 4 tsp 0. 21.8 g 6 tablets 0. 5. 23. Must be refrigerated. Discard after 10 days. 15.000 g 70 kg 1g 1 1/2 qt 3 tsp 6 ounces 30 mg 30 mL 15 mL 0. 12. 26. 17. 22. 17. 11. 50 mL. 20. 13.200 mL 125 mcg 0. 14. 18. 29.Answers 9. 3. 4.5 mg 20. 7. 6. 28. 1 tablet. 500 mg.8 (Tagamet. 300 mg. 6. 7.5 mL 2. 4. 4 tablets 1/2 tablet 3 tablets 5 mL 2 tablets. 5. 7. 4. Ropinirole hydrochloride NDC 0007—4895-20 3 mg 100 tablets Tablets Protect from light and moisture. Augmentin.com 07/11/11 1:53 PM . 7. CTC = No (021) 66485438 66485457 LWBK914-ANS_p337-360.3 (Ancef) 1. 6. 80 mg CHAPTER 8: Oral Dosage Calculations Practice Problems: Pages 166–168 1. FIGURE 7.200 mg 3. Amoxil.352 Answers FIGURE 7. CTC = No www. 1 tablet 4. 1.ketabpezeshki. 3. protect from light and store at 20 to 25 degrees Celsius (room temperature).indd 352 2.4 (Requip) 1. 6. every 6 hr to 8 hr Shake well. 4. 5. Close container tightly after each use. GlaxoSmithKline End of Chapter Review: Pages 144–146 FIGURES 7. Paxil) 1.5 mL.5 mL of sterile water for injection 330 mg/mL (IM use) 250 mg to 1 g. 10. 15 mL 10 mL 2 tablets 1/2 tablet 10 mL. 8. 5. 9. 2. 3. 2. Requip 8. Cefazolin Intramuscular and intravenous Add 2. 3. 2 tablets. 2. Before reconstitution.5 to 7. 6. 30 mg 1 mg 2 mL 4 tablets 0. 8. 8. 17.5 mL 1 mL 0.com 07/11/11 1:53 PM .75 mL 0. 18. 10. 21.5 mL 15 mL. 5. 20.5 mL 2 mL 1. 11. 20. 2 mL 4. 0.indd 353 2. 13. 16.Answers 11. 4.5 mL www. 2 tsp. CTC = Yes CHAPTER 9: Parenteral Dosage Calculations End of Chapter Review: Pages 186–190 1. 4 tablets 2 tsp: 4 tablets 10 mL.8 mL 0.6 mL 0.6 mL 19. ½ tsp. 16. 6.75 mL 2 mL 0.5 mL 2 mL (021) 66485438 66485457 LWBK914-ANS_p337-360. 17. 13. 15. 22. 9. 3. 24. 23. 5. 13.25 mL 0. 11. 14. 2 mL 3 mL 0.6 mL 0. 353 12. 9. 7. 19.3 mL 2½ tablets 15. 14. 18.5 mL 1 tablet. 3 tablets End of Chapter Review: Pages 169–171 1. 3 tablets 30 mL 1 tablet 1 ounce 7.25 mL 1. 10 12. 25. 12.7 mL 0. 4 mL 17.4 mL 0. 7. 16. CTC = No 0.8 mL. 14. 3.75 mL 3 mL 0. 0.ketabpezeshki.8 mL 0. 15. 2 mL 7. 3 tablets 4 tablets 2 tablets 1 tablet 1 tablet 4 tablets 500 mg 4 tablets. CTC = Yes 2. CTC = slower at 15 gtt per min 8. 100 mL per hr 83 mL per hr 63 mL per hr 42 gtt per min 10 gtt per min 12. 25 gtt per 14. 4. CTC = Yes 3.5 mL 4 mL 1. 16. 11. 15. 3. 2.5 mL 1 mL 0. 28. 8 gtt per min 12½ hr 13 gtt per min 38 gtt per min 125 mL www. 17. 28 gtt per min 19 gtt per min 20 hr 12½ hr 42 gtt per min 100 gtt per min (021) 66485438 66485457 LWBK914-ANS_p337-360. CTC = No. 67 gtt per min min. 63 mL per hr 250 mL per hr 50 mL per hr 21 gtt per min 167 mL per hr. CTC = Yes End of Chapter Review: Pages 216–218 1. 8. 27 gtt per min 5.ketabpezeshki. 7. 20. 2. 29. 19 gtt per min 17 gtt per min 10.354 26. 9. 11. 31. Answers 1. 42 gtt per min 6. 10.com 07/11/11 1:53 PM . 18. 50 gtt per min 17 gtt per min 12. Limit injection to 3 mL per site.5 mL 27. 17 gtt per min. 21 gtt per min 7. 5. 13. 125 mL per hr 4. 32. 83 mL per hr.indd 354 2. CHAPTER 10: Intravenous Therapy Practice Problems: Pages 213–215 1. 14. 30. 33.2 mL 0. 9. 19.5 mL 4 mL. 17 gtt per min 19 gtt per min 25 mL. 6. 13. 5. CTC = Increase. 13. 3. 9.5 mL per hr.Answers 355 CHAPTER 11: Intravenous Therapies: Critical Care Applications End of Chapter Review: Pages 233–237 1. 7. 12. 24 mL per hr 2 mL.ketabpezeshki. 80 mcg per min 10 mL per hr 200 mcg per mL.com 07/11/11 1:53 PM . 60 mL per hr 1 mL. 6. 11.2 mL per hr 10 mL. Decrease 6 mL per hr 4 mcg per min 10 mL per hr 14.indd 355 Unit 50 0 45 40 35 30 25 20 15 10 5 USE U-100 ONLY L www.2 mcg/kg/min 3 mL per hr 40 mL. 45 units of U-50 (021) 66485438 66485457 LWBK914-ANS_p337-360.2 mL per hr. 200 mL per hr. 68. 16.2 mcg/kg/min. 6 mL per hr 11. 8. CTC = Yes 4 mg per min 15.2 mL per hr CHAPTER 12: Insulin End of Chapter Review: Pages 254–257 1. 4. 25 mL per hr. 18. 15. CTC = Increase 7. 10 mL per hr 7. 60 units of U-100 90 0 Un t Unit 80 0 1 100 70 0 60 50 40 30 20 10 USE U-100 ONLY L 2. 1 mg per mL. 17.2 mL per hr. 82 units of U-100 USE U-100 ONLY L 3. 3 mL per hr. 10. 14. CTC = decrease 22. 2. 26 units of U-50 6. 14. 5. U-50/0. 60 units 20 units 21.4 mL per hr. 0.indd 356 www. 15. CTC = 15. CTC = Less Than 11.5 mL U-50. is within 10.000 units. 7. 50 units. 39 units.000 units. U-50/0. U-100/1 mL 30.2 mL per hr 22.5 mL 64.4 units/kg/hr 0.480 units. CTC = Yes 20. 6. 400 units per hr.6 mL. CTC = Not Logical 17. is within 0. 15 units 19. NPH CHAPTER 13: Heparin Preparation and Dosage Calculations: Subcutaneous and Intravenous End of Chapter Review: Pages 276–279 1. 30 units. 10. 12. 34 units. U-50/0. 3.000 units. 9.ketabpezeshki.000 units per 8 hr 9. 13.5 mL 38. 56 units of U-100 7. is within. 20. U-50 18.356 Answers 4. 24.com 07/11/11 1:53 PM . safe Yes 20 mL per hr 4. 16. 10. 8.8 mL. 20. 600 units per hr (021) 66485438 66485457 LWBK914-ANS_p337-360.5 mL Unit 1 100 90 0 80 0 70 0 60 0 50 40 30 20 10 USE U-100 ONLY L 8. 35 units of U-50 50 0 Unit 35 45 5 30 40 40 0 25 35 20 30 15 10 5 USE U-100 ONLY L 50 45 25 20 15 10 5 5. 40 units 70 units 45. 0. 4. U-50/0. 11. 2.25 mL 11.6 mL. 8 to 4 mg per dose 4. 90 to 150 mg per day.com 07/11/11 1:53 PM . 1. BSA = 0. 750 to 1. Yes. 5 to 20 mg per day. 30 kg. CTC = No. unsafe 50 mL per hr 21 mL per hr.Answers 12. 357 45. 24-hr total = 900 mg 14.7 mL per hr 13.ketabpezeshki. Yes. 30 kg. 14. 25 to 50 mg per day. 375 to 750 mg.7 m2. is safe. 2. Yes 13. 80 to 120 mg per dose.6 mL End of Chapter Review: Pages 310–316 1. Yes 6. Yes 7. 3.indd 357 www.000. 16. 75 to 150 mg per day. 2. 15 kg. safe dosage range is 300 mg per day 2. 11 mL 5. 25 to 100 mg per day. 625 units per hr 12. 40 kg. is safe 5. is safe 250 mg 20 mg 15 kg. 260 mg.500 mg per day. Yes 12. safe dosage range is 0. safe dosage range is 100 to 200 mg per day 3. 4 mL. Yes. Yes 11. 1 mL.5 mL 15. 13. 100 mg. 15. 4. 50 to 70 mg per dose. 60 kg.1 units/kg/hr CHAPTER 14: Pediatric Dosage Calculations and Intravenous Therapy Practice Problems: Pages 297–300 1. 3 to 6 g per day. Yes 9. Yes 10. 4 mg. Yes 8. 6 mL per q6h = 600 mg per day. No. 300 mg to 600 mg per day. 10 to 20 mg per day. 20 kg. CTC = Yes (021) 66485438 66485457 LWBK914-ANS_p337-360. Yes 600 to 1. 9. 17.200 mg per dose. is safe 40 kg.10 m2.8 mL 0.85 or 1. 21. 30. 8.5 to 10 mg per day. 24. dosage = 31. 11.indd 358 2.5-mg dose 0. 1. 26. Yes No 7. 1. 300 mg. 10. 13. 14.ketabpezeshki.358 6.9 mL 6. 0. 27. Answers 7 mg. Yes 2. 60 mL 0.200 mL 4. 125 mL 5. 20 to 80 mg per dose.6 mL. 2 to 8 mg per dose. 22. 7. 29. 25. is safe 40 kg.200 mg per day. is safe 30 kg. is safe 100 mL per hr 150 mL per hr 100 mL per hr 93 mL per hr 60 mL per hr 150 mL per hr 30 gtt per min 60 gtt per min.5 mL 650 mg per day. 9.5 mL.000 mg. 31. 0. 15. Yes 0. 300 mL. 23. 4 mL.4 mL BSA = 1. Yes Yes 600 to 1.33 mL.5 mL 15 gtt per min CHAPTER 15: Solutions and Drug Reconstitution End of Chapter Review: Pages 327–328 1.75 mg per dose.com 07/11/11 1:53 PM .5 to 24. 16.65 mL 375 to 750 mg per day. 1. 0. 18. 1. 28. 2 mL www. 3 mL (021) 66485438 66485457 LWBK914-ANS_p337-360. 8 g 3.200 mg per day.00 to 1. 19. 20. 12. 375 mL. Yes. 25. Yes 0. 19.7 mL 18. 36. 3 mL 1 mL 12. 38. is a safe dose Yes 20 to 30 mg per dose. 9 mg 6 units/hr 1. 7. 1/2 tablet 8. 1. Yes 20 to 68 mg per day. 0.000 units per hr. 30.1 mL 0. 39. 41. 35.5 mL 450 units per hr 1. 35 units of NPH 0. 42. 200 mL 3 mL 21 gtt per min. 500 mg 6 tablets 4.5 mL. 31.4 g 16 mg 1 tablet. 5.5 mL 3 mL 14. 0.200 mg per day. 15. 23. 2. 0.Answers 359 End of Unit 3 Review: Pages 329–336 1.5 mg/hr 1 vial 2. 20. 5 mL 3 tablets 15 mL. Yes 39 to 48. 27. 40. 29. 17. CTC = Yes 6. 1 mL 1 tablet 10.5 mL 16.5 mL. 1.ketabpezeshki.5 mL 12.75 mg per day. 3. 400 mg.5 mL (021) 66485438 66485457 LWBK914-ANS_p337-360. 13.75 mL. 37. 9. 24. CTC = Greater at 32 gtt/min 50 gtt per min (approximate) 42 gtt per min (approximate) 11 hr.25 mL 1. 0.4 mL.com 07/11/11 1:53 PM . 22. 34. 32. Yes 5 to 10 mg per dose. 28. 11. Yes 1. 43. 26. 33.indd 359 www. 6 min 5 mg/hr 15-unit 10 units of Regular. 21. 3 mL 1. 4.55 3.2 5. 0.47 2.8 1. 2. 1.68 5.2 6. 3. 1.23 6. 0.7 2. 2. 0. 0. 1. 0.ketabpezeshki.360 Answers Appendix B: Rounding Off Decimals Practice Problems: Page 365 1.com 07/11/11 1:53 PM .38 (021) 66485438 66485457 LWBK914-ANS_p337-360.3 4.74 4.indd 360 www.8 3. five (v). 100. the most commonly used letters are shown in Table A-1. 500.com 07/11/11 11:49 AM .APPENDIX A Roman Numerals The use of Roman numerals dates back to ancient times when symbols were used for pharmaceutical computations and record keeping. Lowercase Roman numerals are used to express numbers. The Roman numeral system follows certain rules for arrangement of its numerals.ketabpezeshki. Modern medicine still uses Roman numerals in prescribing medications. follow these steps: 361 (021) 66485438 66485457 LWBK914-App-A_p361-363. and 10 (x). Four numerals are rarely used in practice (50. 1.indd 361 www. R U L E To read and write Roman numerals. The Roman system uses letters to designate numbers. The most common letters you will use are one (i). especially when using the apothecary system of weights and measurement.000) but are included in the table. xvv = 10 + 5 = 15 xxv = 20 + 5 = 25 • Subtract values when the smallest-valued numeral is on the leftt and the largest-valued numeral is on the right.1 Roman Numerals Roman Numeral Equivalents for Arabic Numerals ARABIC NUMERAL ROMAN NUMERAL 1 2 3 4 5 6 7 8 9 10 20 40 50 100 i ii iii iv v vi vii viii ix x xx xL L C • Add values when the largestt valued numeral is on the leftt and the smallestt valued numeral is on the right.com 07/11/11 11:49 AM .ketabpezeshki.indd 362 www.362 APPENDIX A Table A. EXAMPLES: EXAMPLES: ixx = 10 − 1 = 9 iv = 5 − 1 = 4 (021) 66485438 66485457 LWBK914-App-A_p361-363. ketabpezeshki.indd 363 www. EXAMPLES: xiv = (5 − 1) + 10 = 4 + 10 = 14 xix = (10 − 1) + 10 = 9 + 10 = 19 (021) 66485438 66485457 LWBK914-App-A_p361-363.APPENDIX A Roman Numerals 363 • Subtract values first and then add when the smallestvalued numeral is in the middle and the larger values are on either side.com 07/11/11 11:49 AM . 3[1]5. For 36. If it is 5 or greater than 5 (>5).315 would look like this: 36. • Look at the number to the right of the bracket.315 to the nearest hundredth. • Bracket the number [ ] in the hundredths place (2 places to the right of the decimal). For 36.ketabpezeshki. For example.com 07/11/11 11:50 AM . follow these steps: • Determine the place that the decimal is to be “rounded off” to (tenths. 364 (021) 66485438 66485457 LWBK914-App-B_p364-365. Then 36. then increase the bracketed number by 1. hundredths). that number would be 5.indd 364 www. then drop the number. you would bracket the 1.3[1]5. increase the bracketed number [1] by 1.32. For 36.315. let’s round off 36. The rounded off number becomes 36.APPENDIX B Rounding Off Decimals To round off decimals.3[1]5. • If the number to the right of the bracket is less than 5 (<5). ketabpezeshki. 0.737 _____ 3.19 _____ 4. 360. 5.83 _____ 2. 4.66 _____ 6. 2.383 _____ Answers are on p.67. 2.6[7]1 Look at the number to the right of [7].84 _____ Round off to the nearest hundredth.. 1. 1.468 _____ 6.545 _____ 2.APPENDIX B EXAMPLE: Rounding Off Decimals 365 5.indd 365 www. Leave [7] as is.34 _____ 3. 3. 1.67 PRACTICE PROBLEMS Round off to the nearest tenth. (021) 66485438 66485457 LWBK914-App-B_p364-365.19 _____ 5. 0.680 _____ 4. 1.671 rounds off to 5. The number is <5. 0. drop 1.671 5.231 _____ 5. [7] stays as [7].com 07/11/11 11:50 AM . 1. 0. ANSWER: 5. 0. indd 366 www. Some abbreviations frequently used in the past are no longer acceptable.APPENDIX C Abbreviations for Drug Preparation and Administration The Institute for Safe Medication Practices (ISMP) has compiled a list of frequently misinterpreted abbreviations that can cause medication errors.* before Use “at” of each before meals Use “right ear” *Do not use.ismp. The correct approach is to write the word out in full.ketabpezeshki.D. per ISMP recommendations. ABBREVIATION INTERPRETATION a or a @* aa or aa a. A. The complete list can be found at http://www.org.c. 366 (021) 66485438 66485457 LWBK914-App-C_p366-369.com 07/11/11 11:51 AM . d. ID IM IN IV IVPB kg KVO 367 *Do not use. disp.APPENDIX C Abbreviations for Drug Preparation ABBREVIATION INTERPRETATION ad lib. or A. as desired Use “left ear” alternate hour before noon water as soon as possible Use “each ear” twice a day twice a night twice a week with gallon capsule(s) controlled dose centimeter controlled release Use “discontinue” double strength dilute dispense Use “dram” diagnose elixir extract. h. A.w.P. A. A.A.U. ext. b. external gram gallon grain drops hour hypodermic hour of sleep.L. g gal gr gtt h.indd 367 www.i. per ISMP recommendations.* alt.i. b. CD cm CR D/C* DS dil.com 07/11/11 11:51 AM .ketabpezeshki.S. at bedtime intradermal intramuscular intranasal intravenous intravenous piggyback kilogram keep vein open AM aq.i.s. hr Η h. dr Dx elix. − c C cap(s).* b. (021) 66485438 66485457 LWBK914-App-C_p366-369.S.n. P. o. oint o. O.* o.368 APPENDIX C Abbreviations for Drug Preparation ABBREVIATION L LA lb M. min mcg mEq mg mL mm NGT noct. pt q* q. per ISMP recommendations. NOC N.” “every” every morning every hour four times a day every 2 hours every 3 hours *Do not use.a.o.S. or per os* PM p. NS O. o. per p.m.* OTC O. when necessary pint Use “each.D.c..* oz − p p.m. m m.ketabpezeshki..i.d.r. q2h q3h INTERPRETATION liter long acting pound meter minim microgram milliequivalent milligram milliliter millimeter nasogastric tube at night nothing by mouth normal saline solution pint Use “right eye” once every day every hour ointment every morning every night Use “left eye” over-the-counter Use “each eye” ounce after after meals by Use “by mouth” or “orally” evening. before midnight as needed.com 07/11/11 11:51 AM .d. qh q.U.d.h. O. (021) 66485438 66485457 LWBK914-App-C_p366-369.n.n.O. q.indd 368 www. sub q sig. SR stat. subl. SL.o. qt R.ketabpezeshki. susp. s. per ISMP recommendations. tinct.O.c.s. by prescription rule out without Use “one-half” or “½” Use “subcutaneously” or “subcut” label.d.* q.. s.s. write sublingual solution one dose as necessary sustained release immediately suppository suspension tablet tablespoon three times a day tincture to keep open teaspoon ointment vaginally long acting extended release *Do not use.APPENDIX C ABBREVIATION q4h q6h q8h q12h q. tsp. tab tbsp t.q. as much as needed quart rectally to take. soln s.i. rect R/O − s − s− s* SC.com 07/11/11 11:51 AM ..o.indd 369 www. sol. tr T.d. (021) 66485438 66485457 LWBK914-App-C_p366-369. supp. t ung. vag. XL XR Abbreviations for Drug Preparation 369 INTERPRETATION every 4 hours every 6 hours every 8 hours every 12 hours Use “every other day” quantity sufficient.K. 1 mL to 0. Inject slowly until the solution creates a small wheal (blister).2 mL) • Nonirritating solutions that are slowly absorbed • Allergy testing and local anesthesia for invasive tests • PPD administration (screening for tuberculosis) Note: A raised or reddened area indicates a positive reaction The Intradermal Route Use A tuberculin syringe Inject about 1/8 inch Into dermis under the outer layer of skin or epidermis.ketabpezeshki.indd 370 www.com 07/11/11 11:52 AM . Make sure the bevel of the needle is up.APPENDIX D Intradermal Injections The intradermal route is preferred for: • Small quantities of medication (0. 370 (021) 66485438 66485457 LWBK914-App-D_p370-371. [2008]. C. LeMone.5 <0. and Lynn.] Philadelphia: Lippincott Williams & Wilkins. p.) Gauge Needle Length (in. C.1–0. Lillis. P. [6th ed.indd 371 www.. P.ketabpezeshki.) Solution (mL) Range Average Range Average Range Average 27–25 26 3 5 to 8 8 1 2 0. Fundamentals of nursing: The art and science of nursing care. (From Taylor. 834..APPENDIX D Intradermal Injections 371 The Intradermal Route (continued) Angle 15° 15 degrees Site Inner surface of forearm Administering an Intradermal Injection Inserting the needle almost level with the skin.com 07/11/11 11:52 AM ..5 (021) 66485438 66485457 LWBK914-App-D_p370-371. APPENDIX E Subcutaneous Injections The subcutaneous route is used for insulin and heparin. The Subcutaneous Route Use • An insulin syringe • A prefilled disposable syringe with appropriate needle length Inject Under the skin into the adipose tissue below the dermis Angle* 45–90 degrees 45° 90° 372 (021) 66485438 66485457 LWBK914-App-E_p372-373.com 07/11/11 11:53 AM .ketabpezeshki.indd 372 www. ketabpezeshki. Lillis. Philadelphia: Lippincott Williams & Wilkins.) Gauge Needle Length (in. A 90-degree angle of insertion is used with a 3/8" to 1/2" needle for insulin and heparin.indd 373 to Average 5 3 8 8 to 7 8 Solution (mL) Range Average 0. 837. p.APPENDIX E Subcutaneous Injections 373 The Subcutaneous Route (continued) Sites Outer aspect of the upper arm (slow absorption). [2008]. anterior part of thigh (very slow absorption). LeMone.. C.2–2. Fundamentals of nursing: The art and science of nursing care [6th ed..com 07/11/11 11:53 AM . C. Administering a Subcutaneous Injection Bunching tissue around injection site. and upper dorsogluteal (slowest absorption).1 www. P.. and Lynn. P. (From Taylor.0 <0.) Range Average 28–23 26 Range 3 8 (021) 66485438 66485457 LWBK914-App-E_p372-373. codeine sulfate and oxy-morphone hydrochloride. *A 45-degree angle of insertion is used with a 5/8" needle for subcutaneous medications except insulin and heparin—for example. abdomen (rapid absorption).]. ketabpezeshki.0-mL syringe Inject Into the body of a striated muscle. Always aspirate before injecting.APPENDIX F Intramuscular Injections The intramuscular route is preferred for medications that: • Are ineffectively absorbed in the gastrointestinal tract • Require a more rapid onset of action than subcutaneous medications and may have a longer effect • Can be administered in volumes up to 3.com 07/11/11 11:54 AM . 374 (021) 66485438 66485457 LWBK914-App-F_p374-375. Inject past the dermis and subcutaneous tissue.0 mL The Intramuscular Route Use A 3.indd 374 www. 0 1.0–2. vastus lateralis. p.]. deltoid. Philadelphia: Lippincott Williams & Wilkins. Fundamentals of nursing: The art and science of nursing care [4th ed. C..APPENDIX F Intramuscular Injections 375 The Intramuscular Route (continued) Angle Always 90 degrees 90 Sites Ventrogluteal. and dorsogluteal.com 07/11/11 11:54 AM . (From Taylor.5 0.5–5. Depends on patient’s age and the volume of medication. and LeMone.indd 375 www.0 (021) 66485438 66485457 LWBK914-App-F_p374-375.ketabpezeshki. Lillis. Administering an Intramuscular Injection Spreading the skin at site and injecting medication at 90-degree angle. C. P.) Gauge Needle Length (in.) Solution (mL) Range Average Range Average Range Average 25–20 22 1. 607.0 1.. [2001]. com 07/11/11 11:54 AM . This method prevents “tracking” of the medication along the path of the needle during insertion and removal. popular.ketabpezeshki. 376 (021) 66485438 66485457 LWBK914-App-G_p376-378. The method is easy.indd 376 www. and recommended by some institutions as a safe way of administering all intramuscular injections.APPENDIX G Z-Track Injections The Z-trackk method is used for parenteral drug administration when tissue damage from the leakage of irritating medications is expected or when it is essential that all of the medication can be absorbed in the muscle and not in the subcutaneous tissue. (B) Moving the skin to one side.com 07/11/11 11:54 AM ..]. Lillis.indd 377 www. p.. P.) (021) 66485438 66485457 LWBK914-App-G_p376-378. 840.Z-Track Injections APPENDIX G A C 377 B D The Z-track or zigzag technique is recommended for intramuscular injections. C. C. Philadelphia: Lippincott Williams & Wilkins. Fundamentals of nursing: The art and science of nursing care [6th ed.. (D) Once the needle is withdrawn. LeMone. preventing the solution from escaping from the muscle tissue. displaced tissue is allowed to return to its normal position. (C) Needle is inserted at a 90-degree angle. and the nurse aspirates for blood. and Lynn. [2008]. P. (A) Normal skin and tissues.ketabpezeshki. (From Taylor. indd 378 www. Hold the tissues in this displaced position before. and for 5 to 15 seconds after the injection so the medication can begin to be absorbed. Use the IM injection technique as described in Appendix F. the vastus lateralis can also be used. (021) 66485438 66485457 LWBK914-App-G_p376-378. during.ketabpezeshki.0-mL syringe Inject Deep into the body of the gluteal muscle. Angle Always 90 degrees 90° Injection Technique Displace or push tissue over muscle toward the center of the body by displacing the tissue with the last three fingers of the nondominant hand.378 APPENDIX G Z-Track Injections The Z-Track Route Use A 3.com 07/11/11 11:54 AM . 379 (021) 66485438 66485457 LWBK914-App-H_p379-380.indd 379 www.com 07/11/11 11:57 AM . Angle Preferably 45 degrees. May use 90 degrees if the child’s age and body mass warrant it. For infants a 5/8-inch needle may be used.ketabpezeshki.APPENDIX H Pediatric Intramuscular Injections The Intramuscular Route Use A needle about 1 inch in length. Inject Into dense muscle mass in the deltoid and ventrogluteal muscles. Into the outer quadrant of the gluteal and vastus lateralis muscles. Gauge Needle Length (in.5 (> 15 yrs) (021) 66485438 66485457 LWBK914-App-H_p379-380.380 APPENDIX H Pediatric Intramuscular Injections The Intramuscular Route (continued) Injection Technique Similar to the intramuscular technique for adults as described in Appendix F.com 07/11/11 11:57 AM .5–1.5–1.5–1.0–2.5–2.0 (< 3 yrs) 0.5 (4–6 yrs) 0.5 0.5–2.0 0.0 (7–14 yrs) 1.ketabpezeshki.indd 380 www.5 1.) Solution (mL) Range Average Range Average Range Average 22–20 22 0. APPENDIX I Nursing Concerns for Pediatric Drug Administration When administering medications to children. • Reinforce positive behavior with praise and rewards if necessary.ketabpezeshki. and switch roles with the child. encourage the child to pretend. 381 (021) 66485438 66485457 LWBK914-App-I_p381-382.indd 381 www. • Make sure you have obtained an accurate height and weight measurement. • Suggest that the child help as much as possible. • Use supplemental materials to promote understanding (stuffed animals. dolls). you need to be aware of the following: • Explain honestly what will be done.com 07/11/11 12:32 PM . explain at the level of the child’s understanding. ) (021) 66485438 66485457 LWBK914-App-I_p381-382. know toxic and lethal doses. A nurse also needs to understand that the child’s immature body system may respond differently to drugs.com 07/11/11 12:32 PM . • Do not force medication on a frightened child. (See Appendix H for information about pediatric intramuscular injections. • Disguise or dilute medications if necessary. biotransformation. • Always use two people when giving injections to small children.ketabpezeshki. distribution.indd 382 www. especially one who is crying. so there may be changes in an agent’s absorption. and elimination.382 APPENDIX I Pediatric Drug Administration • Be sure that you have compared the safe dosage range with the dosage you plan to give. com 07/11/11 12:33 PM . pulse. the nurse needs to be aware of the following considerations when administering medications to a patient who is critically ill: • Blood pressure. 383 (021) 66485438 66485457 LWBK914-App-J_p383-384. The nurse must possess knowledge of the medications administered and the effect of these medications on vital signs. Therefore. • Drugs may be given to increase blood pressure (vasopressors) or to decrease blood pressure (vasodilators). and heart rhythms must be monitored frequently to titrate medications based on prescribed parameters.APPENDIX J Nursing Considerations for Critical Care Drug Administration A patient who is critically ill may experience rapid hemodynamic changes.indd 383 www.ketabpezeshki. 384 APPENDIX J Critical Care Drug Administration • Calculation of drug dosages and flow rates.indd 384 www.ketabpezeshki. (021) 66485438 66485457 LWBK914-App-J_p383-384. which can be complicated. Some vasopressors. • Drugs are commonly started at a low dose and titrated to achieve the desired effect. • Intravenous medications must be monitored carefully because their effects are immediate.com 07/11/11 12:33 PM . such as dopamine. • Intravenous insertion sites must be monitored closely for signs of infiltration. can cause tissue necrosis. may need to be checked by another nurse or the pharmacist. The nurse must check drug compatibilities before administering two medications together in the same intravenous site. • Critical care patients commonly have multiple drug infusions running at the same time. • The patient must be monitored closely for adverse drug reactions because critical care medications have potent effects. indd 385 www.com 07/11/11 12:34 PM . a tranquilizer may increase restlessness and agitation in an elderly person. frail elderly individuals will probably require less than the normal adult dosages.ketabpezeshki. special consideration is given when administering drugs to anyone who is older than 65 years of age. For example. You should be aware of the following general considerations before administering a drug to any elderly individual. Drug absorption 385 (021) 66485438 66485457 LWBK914-App-K_p385-387. This is because physiologic changes caused by aging change the way the body reacts to certain drugs.APPENDIX K Nursing Concerns for Geriatric Drug Administration As with pediatric medications. • Small. you should check for drug interactions that may cause hazardous effects (e. empty capsules. and diminished tissue perfusion. The cumulative side effects of the drugs being administered must be monitored. decreased muscle mass. if possible. Sedatives and narcotics must be given with extreme caution to elderly people because they may easily become oversedated..com 07/11/11 12:34 PM . Tell the patient not to crush enteric-coated or timereleased drugs.ketabpezeshki. Often.indd 386 www. The problem of impaired hearing should be kept in mind when giving directions or asking questions.386 • • • • • • • • APPENDIX K Geriatric Drug Administration and distribution are affected by decreased gastrointestinal motility. A drug should be given orally rather than parenterally. (021) 66485438 66485457 LWBK914-App-K_p385-387. A drug’s excretion may be altered if the patient has reduced renal blood flow and reduced kidney function. it will be necessary to crush pills. You may have to speak very loudly or repeat the same information several times. or dissolve medications in liquid in order to assist the person to swallow without discomfort. giving a sedative shortly after a tranquilizer).g. A schedule for rotation of injection sites should be followed carefully because the elderly have decreased muscle mass and increased vascular fragility. because decreased activity in the elderly decreases muscle tissue absorption. Because the elderly are often on many different medications. Any written directions for medication administration should be clear and in large print because of possible impaired vision. (021) 66485438 66485457 LWBK914-App-K_p385-387.indd 387 www.com 07/11/11 12:34 PM .ketabpezeshki. • Reinforce any important information by asking the patient to repeat it for you. Memory loss and confusion are common in the elderly because of cerebral arteriosclerosis.APPENDIX K Geriatric Drug Administration 387 Writing the directions is recommended for some patients. This also helps you to ascertain whether the information was understood. indd 388 www. LeMone.) (From Taylor.APPENDIX L Needleless Intravenous System Shown on the next page are a syringe being prepared to be injected into a needleless port and a piggyback setup connected to a needleless port.ketabpezeshki. pp. P.. (Photo by Rick Brady. C. [2008]. P. C. Philadelphia: Lippincott Williams & Wilkins. Fundamentals of nursing: The art and science of nursing care [6th ed.com 07/11/11 12:34 PM .) 388 (021) 66485438 66485457 LWBK914-App-L_p388-389. 792 and 851... and Lynn.]. Lillis. Fundamentals of nursing: The art and science of nursing care [6th ed.indd 389 www.. 792. Philadelphia: Lippincott Williams & Wilkins. (From Taylor..]. p. [2008]. C. P. C.. P. LeMone. and Lynn. P. Lillis. C. Lillis.) Piggyback setup connected to a needleless port. [2008].) (021) 66485438 66485457 LWBK914-App-L_p388-389. (From Taylor.APPENDIX L Needleless Intravenous System 389 Syringe prepared to be injected into a needleless port..]. Philadelphia: Lippincott Williams & Wilkins. C. P. and Lynn.. 851.com 07/11/11 12:34 PM . LeMone.ketabpezeshki.. p. Fundamentals of nursing: The art and science of nursing care [6th ed. This difference. However. 180 (F) and 100 (C).indd 390 www. The differences between the scales. as shown in the following table. forms the basis for the conversion formulas. are based on the differences between the boiling and freezing points.ketabpezeshki. it is still necessary for health care practitioners to understand the differences between the scales and to be able to apply the conversion formulas.APPENDIX M Temperature Conversions: Fahrenheit and Celsius Scales Electronic digital thermometers that convert between temperature scales are popular. 390 (021) 66485438 66485457 LWBK914-App-M_p390-392.com 07/11/11 12:34 PM . APPENDIX M Temperature Conversions 391 Scale Abbreviation Boiling Point Freezing Point Fahrenheit Centigrade F C 212 100 32 0 R U L E To change from Fahrenheit to Celsius. multiply by 5/9. C 100 −32 68 68 5 340 × = 1 9 9 = 340 ÷ 9 = 37. perform the following steps: • Multiply the Celsius reading by 9/5 or 1. • Divide by 9/5 (1. 5 • C (F − ) × 9 EXAMPLE: Convert 100°F to Celsius.ketabpezeshki.7° Celsius R U L E To change from Celsius to Fahrenheit.7°C ANSWER: 37.indd 391 www.8.com 07/11/11 12:34 PM .8) + 32 (021) 66485438 66485457 LWBK914-App-M_p390-392. perform the following steps: • Subtract 32 degrees from the Fahrenheit reading.8) or. • F = (9/5 × C or C × 1. for convenience. • Add 32. 6 37.8 = 72 72 +32 104⬚ ANSWER: 104° Fahrenheit You may find the following temperature conversion scale useful for quick reference.5 102 39 101 38.5 100 38 99 98.392 APPENDIX M EXAMPLE: Temperature Conversions Convert 40°C to Fahrenheit. C 8 40 × 9 = 72 51 or 40 × 1.ketabpezeshki.com 07/11/11 12:34 PM .5 104 40 103 39.indd 392 www.5 37 Celsius Water boils: 100° Water freezes: 0° Temperature conversion scale T (021) 66485438 66485457 LWBK914-App-M_p390-392. F Fahrenheit Water boils: 212° Water freezes: 32° 105 40. dosage calculation based on. 207–208 Calculating oral dosages. 281. 391app. 123t Arabic numerals. 284–286 Brand drug name. 392f Centimeter. pediatric dosage calculation based on. 28–29 with mixed numbers. 109 roman numeral equivalents. 302. 115–117 working in two different systems. 208. A Abbreviations. pounds. 52–53 of fractions. 196. 107t Approximate equivalents. 199–202.com 07/11/11 11:45 AM . 282f Body weight in kilograms vs. 208. 26–28 when denominators are not the same. 362app B Basic math review and refresher. 138 Buretrol set. solving for x. 21–22 Common fractions. changes in units of measurement within the same system. least. 104 Children. 281–282 Apothecary system. 83 Common denominator. 111–113 within the same system. 207–208 Controller. 280–309 Colon format. 105–107 common rules. page numbers followed by f indicate figures. 303f C Calculating flow rates and drug dosages. 122–125 Converting within the same system: metric system. 302 Conversion factor in dimensional analysis. different units. 15–16 Constant factors. 106 common rules. 153. metric. 156–157 Converting dosages between systems. 1–8 Body surface area. 391–392app. 106–107 units of weight and volume. 300. 122–125 Celsius (centigrade) temperature changed to Fahrenheit. 26–31 when denominators are the same.ketabpezeshki. 105. and t following a page number indicates tabular material. 111–113 393 (021) 66485438 66485457 LWBK914-IND_393-400. 147–171 Calculations. 294–297f nomograms for. 300.Index Page numbers followed by app indicate appendices. See pediatric dosage calculations. 30–31 Age. 366–369app Addition of decimals. 152. 392f Fahrenheit changed to.indd 393 www. apothecary and household. 284. solving for x. 237 Chapter 12. 331 intravenous therapies. 167.ketabpezeshki. 61–63 change to fractions. 188. 155 Division of decimals. 366–369app dosage and strength. 370–371app. 115–116 Critical thinking applications intravenous therapies. 138 form. definition of.indd 394 Dimensional analysis. 81–82 intravenous therapies. 371f intramuscular route of. 154 wanted quantity.com 07/11/11 11:45 AM . 329. 57t percents changed to. 123t Drip chambers. 156–157 given quantity. 177. 64. 110f D Deciliter. 140 www. 173. 57–59 of fractions. 9–46 definition of. 381–382app precautions. 57–59. 40–42 mixed numbers in. 219–237 Cups. 203. calculation of. 192 Drop. 195. 171 percent.g. 277. 109 Drop factors. See Intravenous therapies Critical thinking checks Chapter 10. 108t.394 Index Converting within the same system: household and apothecary. nursing concerns for. 233–235. 113 Denominators. 364–365app subtraction of. 278 Chapter 14. 311 Chapter 15. 48f comparing. 10 rounding off. 374–375app. 192 oral route of. 257 Chapter 13. 138–139 geriatric. parenteral dosages (172–190) Dram. 148–168 for medications in the same system and the same unit of measurement. 92–94 parenteral dosages. 41–42 Dosage calculations. 52–53 change from fractions. 190 solutions. 107t. 176. 10 size of. 157–160 for medications in the same system with different units of measurement. 379–380app See also Pediatric dosages. 10 writing. 203t. oral dosages (147–171). 109f. 207 Drops per minute. 214. 192–193. 63–64 change to percents. 10 See also fractions. 164–165 See also specific type. 233–235. 375f intravenous route of. 331 Cross multiplication. 300. 152. 329. 147–171 parenteral. 107. 112. 161–163 for medications in different systems. 9–10 multiplication of. 108. 47–68 addition of.. basic unit. 202–206 Drug administration label abbreviations and symbols for. 237 oral dosages. 13–14 (021) 66485438 66485457 LWBK914-IND_393-400. 9 reading. 75–76 reading. 385–387app intradermal route of. e. 256. 215 Chapter 11. 213. 76 definition of. relative to numerator. 173 pediatric intramuscular. 59t fractions. 148 See also Oral dosages. 53–55 values. 88. 203f Drip rate. critical care applications. 172–190 nursing concerns for. 105–106. 221–231 conversion factor. 47–48 division of. ratio and proportion. 112 Decimals. 51–52 Decimeter. 152–157 calculating dosages and flow rates. 55–57. 11f division of. nursing concerns for. 176–177. unit of weight. 123t Expiration date. 49. convert to kilograms. 33–35 types of and value. 324. systems of measurement. 95–97 Unit 2. 105t www. 78–79 reducing to lowest terms. 16–19 improper. 31–37 when denominators are the same.Index quantity. 329–336 Enteral feeding. label. 40–41 by mixed numbers in. 71–72 proper. 140 Extremes. 152 Fahrenheit temperature Celsius changed to. 376–378app. in proportions. 184–185 E End of unit reviews Unit 1. common. 61–63 changed to percents. 50 decimals changed to. 21–22 multiplication of. 81–82 ratio as.indd 395 395 conversion of. 22–26 improper fraction to a mixed number. label. 15–16 G Gallon. 47–68 addition of. label. 107t Grams. 392f changed to Celsius. 11–12 See also Numerator. 41–42 equivalent (equal). 19–20 relationship to one. 130–131 Unit 3. 137–138 Geriatric drug administration. 39–40 numerator of. 23–24 decimal fraction. 286–287 Gram. 38–39 by mixed numbers. as used in Dimensional analysis. 13–15. 31–32 when denominators are not the same. 30–31 changed to decimals. 15–16 changed to mixed numbers. 373f Z-track method of. 16 concept of size. 80 F Factor label method. 391app.com 07/11/11 11:45 AM . 16–18 Equivalents. 24–26 mixed numbers changed to. 26–28 when denominators are not the same. 11–12 percents changed to. 239–253 penicillin. 10. 138 subcutaneous route of. 28–29 with mixed numbers. 15–16 subtraction of. 377f Drugs measured in units heparin. 300–301 Form of drug. 32–33 with mixed numbers. 104–105. 324–325 Equivalent (equal) fractions. 139 reconstitution or mixing. 72–73 complex. 63–64 definition of. 38–40 by another fraction. 391–392app. 385–387app Grain. 150–152 Fractions. 24–26 mixed number to improper fraction. 14f (021) 66485438 66485457 LWBK914-IND_393-400. 26–31 when denominators are the same. 138–139 Formula method. 372–373app.ketabpezeshki. 108t Generic drug name. 9 denominator of. 105–106. 79 solving for x in. 140 strength and dosage. 9–46 See also Decimals. 259–275 insulin. 392f Feeding pump. intravenous. 40–43 by another fraction. 15 proportions written as. 23–24 least common denominator. 324f Flow rates. 386app intradermal. 300–301 central line. 195. 109f meniscus reading. 370–371app. 375f needleless IV system. 202–206 calculating infusion time using the Standard Formula. 172–190 (021) 66485438 66485457 LWBK914-IND_393-400. 243f Intravenous therapies. 111f converting within the same system.indd 396 geriatric. 265–267 weight–based heparin. 243f mixing two types of. 382app subcutaneous. 300 regulating flow rate. 200. types of. 272t weight-based heparin protocol. 242–244. 204. See also Parenteral dosages. 282f. 194t constant factors. 372–373app. 247t types of and action. 389f pediatric. 272t Household measurements. 271–275. 242–246. 260 intravenous protocol. 108t common rules for. 238–257 administration. 301. 388–389app. 206. 379–380app Infusion devices. 195–196. 203f drip rate. 210 using the Quick Formula. 199–202 H Heparin Preparation and Dosage Calculations. 247–248 sliding scale for coverage. 264 PTT (partial thromboplastin time). 199–202 calculating pediatric flow rate.396 Index Gravity or pump infusions. 122. calculating intravenous. 376–378app. 207–208 critical care applications. 269–271 calculating for subcutaneous injection. nursing concerns. 198–199 Injection(s). 123t linear equivalents. 123t measuring cups. 294–297 intramuscular injection in. 207–208 calculating milliliters per hour. 191–218 calculating drops per minute. 373f z-track. 219–237 calculating dosages and flow rates using Dimensional Analysis. 259. 221–229 drip chambers. 248–252 preparing for injection. 221–229 calculating dosages and flow rates using either ratio and proportion or the Formula Method. 195 common drop factors. 203t commonly prescribed fluids. 107–111 common quantities and metric equivalents. 260f calculating flow rates milliliters per hour. 302 Infusion time. 195. changed to metric. 198–199 gravity or pump infusion. 374–375app. 109–110. 246 continuous IV infusion. 115–117 length in. 268–269 units per hour. 108. 192 www. 197f calculating mL per hour. 246. 252–253 delivery devices. 199–202 pediatric therapy. 240–242. 258–279.ketabpezeshki. 201. 241t types of syringes. 24–25 mixed numbers changed. 23 Infants dosage calculation based on body surface area of. 111f I Improper fractions. 261–263 dosage (units per hour). 283–284. 371f intramuscular. 377f Insulin.com 07/11/11 11:45 AM . 15–16 changed to mixed number. 379–380app nursing concerns for. 281. 139f Lowest terms. 110f Meniscus. 104 system equivalents of. 108. rule and calculations. metric. 193. 146f Labels. 200. 196 secondary lines. 303f via an infusion pump. 19–20 M Math review and refresher. 196. 193–195. 302. 240f Requip. specific medications. 197f. 207–208 use of electronic infusion devices. 139f Kefzol. 110. 203. 199–202 by macrodrip and microdrip. 195–196. 203f the Standard Formula. apothecary and household systems of measurement. 105t pounds converted to. 209f primary line. 240. 137–140 Medicine cup.Index electronic infusion devices. 105t www. 111f Liter. 284–286 L Labels. 122. See drug entries. 136–146 reading and interpreting. 143f. by gravity flow. 109f Medication. 195–196.ketabpezeshki. 102. 139f sample labels Amoxil.indd 397 397 Tagamet. 335f Coreg. 142f Augmentin. 300. 195. 195. 21–22 Length. 195 K Kilograms. 123t Liquid medications. 196. 334f Paxil. 283–284. 137–140. 140 trade. 111–117 Measuring cup. 388–389app. 195 infusion devices. 308–309 needleless system. specific routes of administration Medication labels. 102–105 common rules. 141f. 137–138 manufacturing information. 209 via a PCA pump. 300–309 peripheral line. 208. 239f. in proportions. 1–8 Means. 195 piggyback system. 103 common metric measuments and equivalents. regulating flow rate. 194t infusion sets and lines. medication. 208. reading and interpreting a drug label. See also specific system of measurement. 123t changing dosages within the same system. rule and calculations. brand or proprietary. 193 fluids. 104 Long-acting insulin. 80 Measurement systems. 197. 111f Meter. 211f. 335f (021) 66485438 66485457 LWBK914-IND_393-400. 104 Metric. 195. 108t. 196 via a syringe pump. 220 via a controller. 260f Humulin N. See Labels. 144f Timentin. 175f Heparin sodium. 145f Ancef. 138 Least common denominator. medication. 145f Avandia. household measurement of. reading and interpreting drug name. 193. 195. 110. 102. 197f flow rate.com 07/11/11 11:45 AM . R. 197f IV piggyback (IVPB). 122–125. 197f. specific unit of measure changing dosages when in two different systems. 123t Metric system. 201. 137–140 generic or official. 204 the Quick Formula. 209f IV push. 241t Lot number. 389f pediatric. 220. simplifying or reducing. 195–196. See also Injections calculating medications in different systems of measurement. 389f Nomograms for estimating body surface area. 161–163 Oral or enteral feeding preparations. 319 single-strength. 106. 13–14 Nursing concerns for drug administration in critical care. 104. 9–46 definition of. 386app Multiplication. 108. 123t Microgram. 39–40 subtraction of. 108t linear equivalents. 107t Mixed numbers. 147–171 for medications in different systems. 294–297 calculating flow rate. 111–113 changed to household system. regular insulin mixed with. 105. syringes and needles. 140 National Formulary (NF).398 Index Metric system (Continued) converting within the system. 176t Needleless IV system. See also common fractions. 383–384app (021) 66485438 66485457 LWBK914-IND_393-400. 280–316 calculating dosages based on body surface area (BSA). 57t of fractions. 282–283f. 195. 319–323 definition of. 137 Oral dosages. 24–25 multiplication of fractions by. 381–382app O Official drug name. calculations of. 122 changed to apothecary or household system. 10 size of. 104. 102. 148 Milliliter. 175–176. apothecary. 102. 30–31 changed to improper fractions. 103. 388–389app. 164–165 for medications in the same system and same unit. preparation of. 55–57. 148 Milliliters per hour. 107t. 115. 105t. 300–301 www. 324–325 Oral syringe. 105t. 16 addition of. 282f NPH insulin. 11–12. 157–160 for medications in the same system but different units. 38–40 by mixed numbers. 140 Needle gauge and length. 108. 199–202 Millimeter. cross.com 07/11/11 11:45 AM . 41–42 improper fractions changed to. 177–180 calculating medications in same system but different units. 181–182 calculating powdered medications. calculation of. 248–252 Numerator. 281. nursing concerns for. 319 PCA pump. relative to denominator. 196 Pediatric dosage calculations and intravenous therapy. 33–35 Multiple drug use. 105t Minim. 173 solutions multiple–strength preparation of.ketabpezeshki. 182–184 calculating medications in same system and same units. 109f Ounce. 172–190. 105t. 281. 81–87 of decimals. 173–176 Parenteral dosages. 39–40 N National Drug Code (NCD). 385–387app in pediatric care. 110f P Packaging. 23 division of fractions and. solving for x with. concept of size. 148 Milligram. in elderly.indd 398 in geriatric care. 319–323 Primary line. 289–293 converting weight in pounds to kilograms. 241t Ratio and percents and proportion. 362t reading and writing. 62 R Rapid-acting insulin. of decimals. 78 use of: solving for x. 302–308 intravenous push (IVP). definition of. 70–78 changed to decimals. 364–365app Rx symbol. 108t Quick Formula. 319–323 Reducing fractions to lowest terms. 195 Short-acting insulin. 19–20 Solutes. 284–287 Penicillin. 87–88 with fraction format. 87–88 Reading and interpreting a drug label. 293–294 estimating safe dosage range. 177–185 S Secondary line. 79–81 extremes in. 287–289 intramuscular injections. 326 a solution from a stock solution. 240.com 07/11/11 11:45 AM . 137–140 Reconstitution of medications packaged as powders. 222. 317 Solutions and Drug Reconstitution. 81–87 colon format. 241t Simplifying fractions. 70–71 ratio and proportion. 259. 177. 69–88 solution strength determined by. 78–89 Piggyback delivery system. 58. 207–208 Quotient. 76 definition of. 207 with constant factor. 272t Q Quart. 308–309 calculating oral and parenteral doses. 318 solving for x in. 81–87 verifying accuracy. 107t changed to kilograms. 80 ratio and percents. 362t and Arabic numerals. 324–325 single-strength parenteral solutions. 318 Percents. 71–72 decimals changed to. 79 expressed in the colon format. 271. 70–94 definition. 193. 87–88 (021) 66485438 66485457 LWBK914-IND_393-400. 83 fraction format. 318 reconstitution: preparing injections packaged as powders.Index calculating intravenous medication dosages. 81–82 verifying accuracy. 77. 361–363 Rounding off. 317–336 preparing an oral or enteral feeding. 79 expressed as a fraction. medications packaged as.indd 399 399 with colon format. 108t. 319–323 www. 70 fractions changed to. 284–287 dosage calculations based on body surface area. 184–185 Percentage. 302–309 intravenous piggyback (IBPB). 294–297 estimating body surface area. 361–363app. 80 means in. 195 Proportions definition. 240. 284–286 Powders. 375t nursing concerns for. 381–382app weight conversions. 72–74 health care use of. 209f Pint. 19–20 Roman numerals. 75–76 changed to fractions. 368t Pound(s) apothecary. 319 preparing a topical irrigating solution. decimal point in. 87 PTT (partial thromboplastin time). 374–375app.ketabpezeshki. 200. 87–88 Viscosity. 390–392app (021) 66485438 66485457 LWBK914-IND_393-400. solving for x. 110 Volume apothecary.400 Index Solvents. 242–244. 174. 284–286 metric. 392f from Fahrenheit to Celsius. 204. 373f Subtraction of decimals. 184–185 Unit factor method. drugs measured in. 122–125. 122–125. 152 Unknown. 210 Subcutaneous injection. 174f Lo-Dose syringe. 373f for insulin injections.com 07/11/11 11:45 AM . 81–88 U-50 Lo-Dose syringe. 109. heparin. 201. 249 V Verifying accuracy. Luer-Lok. 271–275. 31–32 when denominators are not the same.indd 400 from Celsius to Fahrenheit. 391–392app. 281.ketabpezeshki. 174f for tuberculin injections. 173–175 standard 3 mL. 294–297 nomograms for. 104–105. 259–275 insulin. 107t metric. 243f packaging and types of. 193 Topical and irrigating solutions. 282–283f. 32–33 of mixed numbers. solving for. 108t. preparation of. 371f for intramuscular injections. 243f U-100 syringe. 243f. 206. 81–87 verifying accuracy. 33–35 Surface area. 108t W Weight apothecary. 108t. 243. 391app.174f Syringe pump. pounds for. 247. 293 X-Z x. 370app. 239–253 penicillin. 242. See Solving for x. 140 Units. dosage calculation based on. 138 U United States Pharmacopeia (USP). 105t system equivalents of. 326 Trade name. 372–373 app. 53–55 of fractions. 116 fraction format in. 366–369 Syringes for heparin injections. 107t gram. 175. 123t use of ratio and proportion. 377f www. 392f Titration. 282–283f Symbols and abbreviations. 376–378app. 83 cross-multiplication. 281. 123t Weight–based heparin protocol. 282–283f. 81–82 in system conversions of volume or weight. 31–35 when denominators are the same. 87–88 Standard Formula. definition of. 240. See Solving for x. 176–177. 123t T Tablespoon. 243f for intradermal injections. 123t Teaspoon. 81–88 Z-track injections. 317 Solving for x colon format in. 174. 196 System equivalents and system conversions. 122–125. 123t Temperature conversions. 105t kilograms vs. 272t West nomogram. 260–261. indd 1 www.2 68 Kg. Divide 150 by 2.2 pounds 30 milliliters 2 pints 4 quarts — 1 grain 15 grains 8 drams — TEMPERATURE CONVERSIONS Celsius to Fahrenheit F= F= 9 C + 32 5 9 × 40°C = 72 + 32 = 104°F 5 Fahrenheit to Celsius C = (F − 32) ÷ 9 5 or × 5 9 C = (68° − 32°) = 36°× 5 = 20°C 9 BODY WEIGHT CONVERSIONS Change 150 lbs to Kilograms. Change 60 Kgs to Pounds.com 07/11/11 12:40 PM . Change an Infant’s Weight in Grams to Kilograms. Divide by 1. (021) 66485438 66485457 Plastic Card.000.Volume and Weight Equivalents Metric System Apothecary System Household Measurements — 4–5 milliliters 15 milliliters 180 milliliters 240 milliliters 1 minim 1 dram 4 drams (3–4 teaspoons) 1 ounce (8 drams) 6 ounces 8 ounces 500 milliliters 1 pint 1000 milliliters (1 liter) — — 1 mg (1000 mcg) 60–65 milligrams 1 gram (1000 mg) 30 grams 1 kilogram (1000 grams) 1 quart 1 drop (gtt) 1 teaspoon 1 tablespoon (1/2 ounce) 2 tablespoons (1 ounce) 1 teacup 1 glass/ measuring cup 1 pint (16 ounces) 1 quart (32 ounces) 1 quart 1 gallon — — — 1 ounce 2. Multiply 60 2.ketabpezeshki.2 132 lbs. 000 = 480 min 480 31.MEDICATION CALCULATIONS Ratio and Proportion 1 gram : 15 grains :: 0.ketabpezeshki.indd 2 www.25 gtt/min or 31 gtt/min CALCULATE ML/HR FOR ELECTRONIC INFUSION PUMP Amount of Solution mL/hr = Minutes to Give 60 min x mL 50 mL = 30 min 60 min 30 x = 3000 x = 100 mL/hr (021) 66485438 66485457 Plastic Card.com 07/11/11 12:40 PM .6 mL /hr or 167 6 Total Time (minutes) gtt/min 1000 mL ×15 15.8 grams : x grains Means Extremes 1x 0.8 15 1x 12 x 12 grains IV FLOW RATE Calculate mL/hr Total Volume Total Time (hours) Calculate Drops Per Minute mL / hr Total Volume Drop Factor 1000 mL = 166.