Studies in burns, XVI: The effect of surgical trauma on metabolic heat production.

As part of an ongoing study of the naturally-occurring skin lipid ethyl linoleate as an adjunct for reducing post-burn hypermetabolism and hyperevaporation, we have conducted a series of evaluations of metabolic heat production (M) using a clinical partitional calorimeter. In this article, we describe the metabolic chamber and its use in evaluating the change in M in pre- and postoperative patients. We determined that dry heat losses (radiation and convection) comprise the major components of heat loss in the "normal" and traumatized individual with intact skin. In the post-operative state, metabolic heat production increases significantly above the preoperative levels, the percentage of change being accurately described by a first order exponential equation. In the postoperative patient, possibly because of a physiologic shift in source of metabolic substrate, stored heat increases significantly. These data may be useful in allowing approximate correction of the metabolic heat equation when studying the burn patient where no "control" is attainable and where some approximation of the contribution of "pure" trauma must be made.