The body surface area of Saudi newborns

Cancer chemotherapy drugs, fluids and electrolytes are best dosed per square meter of body surface area (BSA). Since newborns have an exceptionally large surface to mass ratio, their BSA needs to be accurately estimated, if it is to serve as a safe denominator for drugs and fluids. In this study, BSA was measured directly in 15 full-term Saudi newborns, using a coating technique. The data was used to construct a BSA weight-length prediction formula. Mean body mass index (BMI +/-SD) of our subjects was 12.56 +/- 1.29 kg/m2 and surface to mass ratio, .068 +/- .005 m2/kg. The closest fit to measured values was given by the regression equation: BSA (m2) = 0.03614H(0.294)W(0.529) +/- 0.0027 (SEE) A simplified formula based on weight alone: BSA = 7.4 + 4.2W +/- 0.0022(SEE) was derived for bedside use, in urgent situations. Our formulae may be applicable to non-Saudi newborns, if as expected, body size and shape variations in different populations develop after birth.