Correlation Between Measured Energy Expenditure and Clinically Obtained Variables in Trauma and Sepsis Patients

Background: Indirect calorimetry is the preferred method for determining caloric requirements of patients, but availability of the device is limited by high cost. A study was therefore conducted to determine whether clinically obtainable variables could be used to predict metabolic rate. Methods: Patients with severe trauma or sepsis who required mechanical ventilation were measured by an open-circuit indirect calorimeter. Several clinical variables were obtained simultaneously. Measurements were repeated every 12 hours for up to 10 days. Results: Twenty-six trauma and 30 sepsis patients were measured 423 times. Mean resting energy expenditure was 36 ± 7 kcal/kg (trauma) vs 45 ± 8 kcal/kg (sepsis) (p < .0001). The single strongest correlate with resting energy expenditure was minute ventilation (R2 = 0.61, p < .0001). Doses of dopamine, dobutamine, morphine, fentanyl, and neuromuscular blocking agents each correlated positively with resting energy expenditure. In the case of the inotropics and neuromuscul...