Use of bioelectrical impedance analysis measurements in the clinical management of critical illness

I review the utility of bioelectrical impedance analysis (BIA) for assessing changes in body composition and content and distribution of body water in critically ill patients. Published studies suggest that resistance measurements provide a reasonable estimate of total body water but that the precision of the measurements is poor. Presently, BIA does not appear to be a useful clinical technique for measuring changes in body composition. Despite the limitations of current technology, the utility and efficacy of BIA merit evaluation in large, longitudinal studies if our understanding of the meaning of changes in the electrical properties of the body is to improve.