Nomogram method
The nomograms have three columns, height, weight and BSA, they are based on the DuBois and DuBois formula:
$$ BSA \ (m^2) = { H^ { 0.725 } \times W^ { 0.425 } \times 0.007184 } $$
Nomograms for children and adults are shown below. The BSA of an individual can be estimated by drawing a straight line connecting the individual’s height and weight. The point at which the line intersects the BSA column indicates the BSA of the individual.
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Solved Problem: The recommended adult dose of a drug is 70 mg/m2. Using the nomogram calculate the dose for a child weighing 25 kg and measuring 70 cm. Approach: Estimate the BSA using the nomogram for children. $$ BSA = 0.61 m^2 $$ $$ 70 {mg/m^2} \times 0.61 m^2 = 43 \ mg $$ Answer: 43 mg |
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Solved Problem: The recommended adult dose of a drug is 65 mg, what would be the dose for a child weighing 30 lb and measuring 25 inches, use the nomogram method to determine the BSA. Approach: $$ BSA = 0.44 m^2 $$ $$ Patient's Dose = {0.44 \ m^2 \over 1.73 \ m^2 } { \times 65 \ mg }$$ Answer: 16.5 mg |