RELATIONSHIPS BETWEEN RESTING AND TOTAL-ENERGY EXPENDITURE IN INJUREDAND SEPTIC PATIENTS

Objective: To quantify resting and total energy expenditure in patient s who have suffered severe trauma and sepsis. Design: Prospective, unb linded, observational, nonrandomized study. Setting: Critical care uni t of a Level I adult trauma center. Patients: Immediate posttrauma pat ients or trauma patients exhibiting signs of sepsis with multiple orga n dysfunction. Interventions: An indirect calorimeter was used to meas ure energy expenditure at rest (resting energy expenditure) at 0700 an d 1900 hrs. The energy expenditure measurement was then continued for up to 12 hrs (total energy expenditure). Clinical data were collected for computation of an illness severity score. Results: Thirteen trauma and 20 septic patients were studied 240 times. Ah patients were mecha nically ventilated. Morphine or fentanyl was infused during 99% of stu dies. Neuromuscular blocking agents were used in 42% of septic studies . Both the trauma and septic groups were hypermetabolic (mean trauma r esting energy expenditure, 36 +/- 6 kcal/kg; mean septic resting energ y expenditure, 44 +/- 8 kcal/kg; p < .05). Total energy expenditure wa s similar to resting energy expenditure (trauma total energy expenditu re = resting energy expenditure x 1.035 +/- 0.078, septic total energy expenditure = resting energy expenditure x 1.039 +/- 0.071). Total en ergy expenditure and resting energy expenditure were linearly related (r(2) = .89, p < .0001). Conclusions: Trauma and septic patients are h ypermetabolic, even when heavily sedated or medically paralyzed. A mea surement of resting energy expenditure is a close approximation of tot al energy expenditure in most patients.