A formula for the estimation of the body surface area of Saudi male adults.

OBJECTIVE

Human body surface area (BSA) is the preferred denominator for physiological indices of body metabolism and for drug dosages. The Du Bois and Du Bois height/weight nomogram, used for fast and convenient estimation of patients BSA, is not suitable for all populations due to ethnic differences in body shape and build. The purpose of this study was to obtain direct measurements of BSA and use the data to construct a prediction formula for Saudi male adults.

METHODS

Body surface area was measured in 21 adult male Saudis at Assir Central Hospital in Abha, Kingdom of Saudi Arabia between 2000 and 2003, using a coating technique. Areas of the coating material were determined with a compensating planimeter. Other anthropometric indices were measured or calculated according to standard procedures. Measured values of BSA were subjected to linear regression analysis using the least squares method to obtain a formula for predicting BSA from heights and weights.

RESULTS

Mean body mass index (BMI) was 25.1 +/- 1.6 kg/m2; linearity, 2.46 +/- 0.13 cm/kg; surface to mass ratio, 0.025 +/- 0.0008 m2/kg; relative sitting height (RSH), 0.51 +/- 0.005. The closest fit to measured BSA values was given by the biexponential regression equation: BSA=0.02036 x H(0.516) x W(0.427) +/- 0.01283. This formula predicts BSA of Saudi male adults more accurately than all existing equations tested and yields a convenient BSA table for Saudis.

CONCLUSION

The use of our formula, with prediction accuracy superior to those of existing formulae, should facilitate the establishment of normal values of other physiological indices. It should also lead to more reliable and precise drug dosages and expedite rapid decision making in critical care situations.