1. Adult and Pediatric Dosages Based on Body Surface Area
Chapter 14
Adult and Pediatric Dosages Based on Body Surface Area

2. General Information About Body Surface Area (BSA)
Major factor in calculating medication dosages for both children and adults when body’s physiologic processes are more closely related to body surface than to weight

3. Calculating BSA
Calculated in square meters (m2) using client’s weight and height
Use calculator with square root capabilities

4. Medications Frequently Dosed According to BSA
Antineoplastic agents
Medications prescribed for clients with severe burns

5. BSA Formulas One formula uses kg and cm measurements
BSA = square root of
One formula uses lb and inch measurements

6. Calculating BSA from kg and cm: Example 1
Calculate BSA of client with weight of 104 kg and height of 191 cm
Express BSA to nearest hundredths

7. Calculating BSA from kg and cm: Example 1
Square root of = 2.35 m2

8. Calculating BSA from kg and cm: Example 2
Calculate BSA of client with weight of 59 kg and height of cm
Express BSA to nearest hundredths

9. Calculating BSA from kg and cm: Example 2
Square root of = 1.61 m2

10. Calculating BSA from lb and in: Example 1
Calculate BSA of child with weight of 34 lb and height of 24 in
Express BSA to nearest hundredths

11. Calculating BSA from lb and in: Example 1
Square root of = 0.51 m2

12. Calculating BSA from lb and in: Example 2
Calculate BSA of adult with weight of lb and height of 61.3 in
Express BSA to nearest hundredths

13. Calculating BSA from lb and in: Example 2
Square root of = 1.67 m2

14. Dosage Calculation Based on BSA
Once BSA known, simple multiplication to calculate dosage

15. Calculating Dosage: Example 1
Dosage safe/recommended 5 mg per m2
Child BSA of 1.1 m2

16. Calculating Dosage: Example 2
Dosage safe/recommended 25 to 50 mg per m2
Child BSA of 0.76 m2
Lower dosage:
Upper dosage:

17. Assessing Prescriptions Based on BSA
Typically refer to drug literature to determine safe/recommended dosages for medications prescribed
If drug label for medication available, safe/recommended dosage ranges printed on side label

18. Calculating Dosages
Calculation steps same whether using medication labels or other drug literature

19. Before Beginning Read carefully
Safe/Recommended dosage ranges may be based on total daily dose or individual dose

20. Daily Dosage Ranges
If range based on daily dose, divide daily dose by number of doses client receives per day

21. Two-Step Calculation Process
Client’s BSA placed into range formula to determine safe/recommended dosage
Compare result to prescribed dosage to determine if prescribed dosage safe/recommended for this client