The metabolic basis of the increase in energy expenditure in severely burned patients

Background: Severe burn trauma is characterized by an elevated rate of whol e-body energy expenditure. Approach: In this short review, we have attempte d to assess the metabolic characteristics of and basis for the persistent i ncrease in energy expenditure during the flow phase of the injury. We consi der some aspects of normal energy metabolism, including the contribution of the major adenosine triphosphate (ATP)-consuming reactions to the standard or basal metabolic rate. Rate estimates are compiled from the literature f or a number of these reactions in healthy adults and burned patients, and t he values are related to the increased rates of whole-body energy expenditu re with burn injury. Results: Whole-body protein synthesis, gluconeogenesis , urea production, and substrate cycles (total fatty acid and glycolytic-gl uconeogenic) account for approximately 22%, 11%, 3%, 17%, and 4%, respectiv ely, of the burn-induced increase in total energy expenditure. Conclusions: These ATP-consuming reactions, therefore, seem to explain approximately 57 % of the increase in energy expenditure. The remainder of the increase may be due, in large part, to altered Na+-K+-ATPase activity and increased prot on leakage across the mitochondrial membrane.