1. Math Basics for the Health Care Professional UNIT Copyright © 2014, 2009 by Pearson Education, Inc. All Rights Reserved FOURTH EDITION Basic Dosage by Body Weight 14

2. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Student Learning Outcomes 1.Calculate dosage by body weight 2.Convert weights between pounds and kilograms 3.Calculate individual and daily dosages

3. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Dosing Based on Weight (in kg) Clinical dosing is amount per weight (in kg).  Rx: medication amount per patient weight for a specific time  Rx: Methotrexate sodium IV 2.5 milligrams per kilogram every 14 days 14-1

4. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Dosing Based on Weight (in kg) Calculate the dose:  Rx = 2.5 mg × patient weight (in kg) Example: Compute dosing for a 68 kg patient.  Dose = 2.5 mg × 68 = 170 mg (every 14 days) 14-1

5. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Conversion: lb  kg Converting from pounds to kilograms  Formula: 1 lb = 0.45 kg (lb  kg) Converting from kilograms to pounds  Formula: 1 kg = 2.2 lb (kg  lb) Math Sense: For calculating accurate dosages, the kg weight is rounded to the nearest hundredth for “dosage by weight” calculations. Math Sense: For calculating accurate dosages, the kg weight is rounded to the nearest hundredth for “dosage by weight” calculations. 14-2

6. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Conversion Problem Problem: The patient weighs 32 pounds. What is his weight in kilograms?  Formula: 1 kg = 2.2 lb  Solve by proportion: 14-2

7. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Conversion Problem (again) Problem: The patient weighs 32 pounds. What is his weight in kilograms?  Formula: 1 kg = 2.2 lb  Solve by dimensional analysis: 14-2

8. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Conversion: pounds and ounces  kilograms Converting lbs and oz  Formula: 1 lb = 16 oz Example: Convert 14 lbs 4 oz to kg.  14 lbs 4 oz = 14-2 Now convert to kilograms

9. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Conversion Problem Problem: Convert 25 lbs 10 oz to kg.  Formula: 1 lb = 16 oz 14-2 Now convert to kilograms

10. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Calculating Dosage Problem: The nurse receives a medication order for a child: Vancomycin hydrochloride 40 milligrams per kilogram per day in four divided doses for 10 days, not to exceed 2 grams a day. The child weighs 34 pounds 6 ounces. What is the total daily dose? What is the individual dose? 14-1, 14-3

11. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Calculating Dosage (continued) Problem: The nurse receives a medication order for a child: Vancomycin hydrochloride 40 milligrams per kilogram per day in four divided doses for 10 days, not to exceed 2 grams a day. The child weighs 34.38 pounds. What is the total daily dose? What is the individual dose 14-1, 14-3

12. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Calculating Dosage (continued) Formula: 1 kg = 2.2 lb 14-1, 14-3

13. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Calculating Dosage (continued) Problem: The nurse receives a medication order for a child: Vancomycin hydrochloride 40 milligrams per kilogram per day in four divided doses for 10 days, not to exceed 2 grams a day. The child weighs 15.63 kg. What is the total daily dose? What is the individual dose? 14-1, 14-3

14. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Calculating Dosage (continued) Problem: 14-1, 14-3

15. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Solving by Dimensional Analysis Problem: The nurse receives a medication order for a child: Vancomycin hydrochloride 40 milligrams per kilogram per day in four divided doses for 10 days, not to exceed 2 grams a day. The child weighs 34 pounds 6 ounces. What is the total daily dose? What is the individual dose? 14-1, 14-3

16. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Solving by Dimensional Analysis Problem: 14-1, 14-3 First change the lbs & oz into the decimal form... 34 lb 6 oz  34 6 16 lbs = 34.375 lbs = 34.38 lbs

17. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Continuing on… Problem: The nurse receives a medication order for a child: Vancomycin hydrochloride 40 milligrams per kilogram per day in four divided doses for 10 days, not to exceed 2 grams a day. The child weighs 34.38 pounds. What is the total daily dose? What is the individual dose? 14-1, 14-3

18. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Continuing on… Problem: 1 kg = 2.2 lb 14-1, 14-3

19. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Continuing… Problem: The nurse receives a medication order for a child: Vancomycin hydrochloride 40 milligrams per kilogram per day in four divided doses for 10 days, not to exceed 2 grams a day. The child weighs 15.63 kg. What is the total daily dose? What is the individual dose? 14-1, 14-3

20. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Continuing… Problem: 14-1, 14-3

21. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Continuing… Problem: The nurse receives a medication order for a child: Vancomycin hydrochloride 40 milligrams per kilogram per day in four divided doses for 10 days, not to exceed 2 grams a day. The child weighs 15.63 kg. What is the total daily dose? What is the individual dose? 14-1, 14-3

22. Math Basics for the Health Care Professional, Fourth Edition Michele Benjamin Lesmeister Continuing… Problem: 14-1, 14-3