Measures of body surface area in children

Abstract

Body surface area (BSA) is an important index of body size in both adults and children. The use of BSA allows for standardization of the important physiological parameters such as cardiac function, glomerular filtration rate and proteinuria, which are indexed by BSA. This in turn enables comparison of these parameters among children of various ages and sizes. In addition, BSA has been frequently used in children for the dosing of diagnostic and therapeutic drugs. The estimation of a correct BSA is therefore of crucial importance in both diagnostic and therapeutic aspects of pediatric medicine. Methods for direct estimation of BSA, such as coating methods, alginate methods or threedimensional scanning, yield precise results but are not suitable for bedside use where only indirect methods for BSA estimation can be used. They are mostly based on mathematical formulae containing weight alone or both weight and height as parameters. Although there are numerous BSA formulae published in the literature, only few have been validated in children. Formulae with weight as the only parameter tend to underestimate or overestimate the BSA. Most published pediatric formulae with both weight and height yield similar results with only minor, yet not clinically important differences. Therefore, the BSA formulae are suitable for use in all children up to the age of 18 years, with the exception of newborns in whom the selection of suitable BSA formulae is limited. The formula by Mosteller et al., where the BSA (m2) = square root of [height (cm) × weight (kg)/3,600], seems to be the most universal and user friendly formula for children of all age categories.