The hypermetabolic response seen in patients with large burns, who are successfully resuscitated, is thought to be driven by which of the following factors?

a. Deficient gastrointestinal barrier function

b. Bacterial contamination of the burn wound

c. Evaporative heat loss d. Changes in hypothalami

d. Changes in hypothalamic function

The physiologic challenge of a burn in excess of 20% of the body surface frequently results in an initial decrease in cardiac output and metabolic rate. Subsequently, effected by a complex cascade of mediators, a hypermetabolic response is seen with a near doubling of cardiac output and resting energy expenditure over the next 24 to 48 hours in those who are successfully resuscitated. The magnitude of this response peaks in those with injuries of 60% or more of the body surface at as high as twice the normal basal metabolic rate. The etiology of the hypermetabolic response is not entirely understood but is assumed to involve a combination of factors including a change in hypothalamic function with coincident increases in glucagon, cortisol and catecholamine secretion, deficient gastrointestinal barrier function with translocation of bacteria and their byproducts, bacterial contamination of the burn wound with systemic release of similar products from this source, and some element of enhanced heat loss via transeschar evaporation of fluid. An important element of successful management of patients who have sustained large injuries is support of this response through the provision of adequate quantity and quality of substrate.