The influence of body mass index on burn surface area estimated from the area of the hand

It is well recognised that initial estimates of the area involved in a burn injury by inexperienced clinicians are frequently excessive. In Britain the palmar surface area of the hand is taught to approximate 1% of the total body surface area (TBSA), but no allowance is made for variations in individual body weight. This study aimed to evaluate the relationship between hand surface area (HSA) and body mass index (BMI) using healthy volunteers. We found that mean HSA diminished significantly as BMI increased in both sexes (P<0.001). This effect was, however, more pronounced in women, particularly those with a BMI greater than 31 kg/m2 in whom the HSA represented only 0.64%. Awareness of the potential for over-estimation of burn surface area using this method alone may improve the accuracy of burn area estimation and consequent need for commencing resuscitation.