A NEW METHOD FOR THE ESTIMATION OF THE COMPONENTS OF ENERGY-EXPENDITURE IN PATIENTS WITH MAJOR TRAUMA

The management of critically ill patients would be better understood i f the total energy expenditure (TEE) and its components were known. To quantify the different components of energy expenditure in patients w ith major trauma, we used a technique combining measurements of body c omposition and oxygen consumption. We determined changes in body weigh t, total body water, total body protein, total body potassium, total b ody fat, and bone mineral content every 5 days over a 10-day period in a group of nine multiply injured patients. Resting energy expenditure was measured by indirect calorimetry (REE(m)), and a predicted value was obtained from total body potassium (REE(p)). TEE was assessed by a dding the total calorie intake to the changes in body energy stores, a nd the activity energy expenditure (AEE) was calculated by subtracting REE(m) from TEE. Mean daily values for REE(m), REE(p), TEE, and AEE w ere 2,236 +/- 140, 1,683 +/- 82, 3,029 +/- 276, and 793 +/- 213 kcal/d ay, respectively, over the 10-day study period. Although not statistic ally significant, the mean AEE was four times smaller for the first 5 days of study than for the second 5 days (298 +/- 400 vs. 1,254 +/- 58 8 kcal/day). The technique of combining indirect calorimetry and body composition measurements offers a new approach to evaluate energy expe nditure and a new way to study metabolic disorders and therapeutic str ategies in critically ill patients.