Development and validation of a length- and habitus-based method of ideal and lean body weight estimation for critically ill adults requiring urgent weight-based medical intervention

Objective: Accurate drug dosing in obese patients requires an estimation of ideal body weight (IBW) or lean body weight (LBW) for dosing hydrophilic medications. Erroneous weight estimates during the management of critically ill adults may contribute to poor outcomes. Existing methods of IBW and LBW estimation or measurement are very difficult to use during emergency care. A new point-of-care model is needed to provide rapid estimates of IBW and LBW for this purpose. Methods A model was derived based on the PAWPER XL-MAC tape, a pediatric weight estimation system, which uses recumbent length and mid-arm circumference to estimate IBW and LBW. The model was used to generate weight estimations in a derivation sample (n=33155) and a validation sample (n=5926) from National Health and Nutrition Examination Survey (NHANES) datasets. The outcome measure was to achieve >95% of IBW and LBW estimations within 20% of recognized reference standards (P20>95%) and >70% of estimations within 10% of these standards (P10>70%). Main Results: The new model achieved a P20 of 100% and a P10 of 99.9% for IBW and a P20 of 98.3% and a P10 of 78.3% for LBW. This accuracy was maintained in both sexes, all ages, all ethnic groups, all lengths and in all habitus-types, except for the morbidly obese female subgroup. Conclusions The modified PAWPER XL-MAC model proved to be an accurate method of IBW and LBW estimation. It could, therefore, have an important role in facilitating emergency drug dose calculations in acutely or critically ill obese adult patients. Conclusions The modified PAWPER XL-MAC model proved to be an accurate method of IBW and LBW estimation. It could, therefore, have an important role in facilitating emergency drug dose calculations in acutely or critically ill obese adult patients.