Two methods for estimating body surface area in adult amputees

Two methods for estimating body surface area (BSA) in adult amputees were developed. BSA in sq m was determined in 42 healthy, nonamputee men and women by summing the surface areas of individual body parts obtained using geometric measurements (BSAmeas) and by an equation using height and weight (BSAcalc). Linear regression analysis was used to determine correlations between BSAmeas and BSAcalc and between BSAmeas and surface-area measurements of individual body parts (SApart). The percentages of total BSA contributed by individual body parts in each subject were determined by the ratio of SApart to BSAmeas, and these percentages were compared with the corresponding percentages for body parts using the "Rule of Nines." BSAcalc and BSAmeas were significantly correlated, as were SApart and BSAmeas. Regression analysis of SApart versus BSAmeas yielded an equation for each measured body part that allowed calculation of SApart without direct measurement. SApart expressed as a percentage of total BSA differed from the percentage of BSA used in the "Rule of Nines" by a mean of 12.4-32% depending on the body part. Two methods of estimating BSA in amputees were proposed based on deduction of the surface area of the amputated part (calculated from the regression equation for SApart or as a percentage of total BSA) from total BSAcalc in adult amputees. The two methods developed in this study for estimating BSA may be useful in determining drug dosages in adult amputees and may provide more accurate information in burn therapy. Further studies are needed to validate the clinical application of these methods.