Components of energy expenditure in patients with severe sepsis and major trauma: A basis for clinical care

Objective: To obtain accurate values for the components of energy expenditu re in critically ill patients with sepsis or trauma during the first 2 wks after admission to the intensive care unit. Design:Prospective study. Setting: Critical care unit and university department of surgery in a singl e tertiary care center. Patients: Twelve severely septic (median Acute Physiology and Chronic Healt h Evaluation II Score, 23; range, 15 to 34) and 12 major trauma patients (m edian Injury Severity Score, 33.5; range, 26 to 50). I nterventions: Total body fat, total body protein, and total body glycogen w ere measured as soon as hemodynamic stability had been reached and repeated 5 and 10 days later. Resting energy expenditure (REE) was measured daily b y indirect calorimetry. Measurements and Main Results:Changes in total body fat, total body protein , and total body glycogen in critically ill patients provide data for the a ccurate construction of an energy balance. Energy intake minus energy balan ce gives a direct measurement of total energy expenditure (TEE) and, when c ombined with measurements of REE, activity energy expenditure can be obtain ed. TEE, REE, and activity energy expenditure were calculated for two seque ntial 5-day study periods. REE progressively increased during the first wee k after the onset of severe sepsis or major trauma, peaking during the seco nd week at 37 +/- 6% (SEM) and 60 +/- 13% greater than predicted, respectiv ely. For both the sepsis and trauma patients, TEE was significantly higher during the second week than during the first week (3257 +/- 370 vs. 1927 +/ - 370 kcal/day, p < .05, in sepsis; 4123 +/- 518 vs. 2380 +/- 422 kcal/day, p < .05, in trauma). During the first week after admission to the hospital , TEE in sepsis and trauma patients, respectively, averaged 25 +/- 5 and 31 +/- 6 kcal/kg of body weight/day, and during the second week, 47 +/- 6 and 59 +/- 7 kcal/kg/day (p < .03, for comparison of first and second weeks). For the first week, the ratio of TEE to REE was 1.0 +/- 0.2 and 1.1 +/- 0.2 but during the second week rose to 1.7 +/- 0.2 and 1.8 +/- 0.2 in patients with sepsis (p < .05, for comparison of weeks) and trauma (p = .09), respe ctively. Conclusions:Total energy expenditure is maximal during the second week afte r admission to the critical care unit, reaching 50 to 60 kcal/kg/day.