Similar metabolic responses to standardized total parenteral nutrition of septic and nonseptic critically ill patients.

BACKGROUND Nutritional support is an important link between the response to injury and recovery in critical illness. OBJECTIVE Our goal was to evaluate energy and substrate metabolism in septic and nonseptic critically ill patients in the resting state and during the administration of standardized total parenteral nutrition. DESIGN This was a prospective, clinical cohort study of 25 consecutively admitted critically ill patients either with (n = 14) or without (n = 11) sepsis who received total parenteral nutrition. Resting energy expenditure was measured on days 0, 2, and 7 by indirect calorimetry. Energy and substrate balances were calculated on days 2 and 7. RESULTS Resting energy expenditure was not significantly different between septic and nonseptic patients on day 0 (2.65 +/- 0.49 and 2.36 +/- 0.56 kJ x min(-1) x m(-2), respectively). Energy balances were positive for both groups on days 2 (0.68 +/- 0.4 and 0.74 +/- 0.6 kJ x min(-1) x m(-2), respectively; NS) and 7 (0.65 +/- 0.3 and 0.78 +/- 0.5 kJ x min(-1) x m(-2), respectively; NS). Substrate balances were not significantly different between groups on days 0, 2, and 7. Resting energy expenditure on day 0 was negatively correlated with the severity of illness in septic patients only (r = -0.58, P < 0.05). CONCLUSIONS Metabolic changes were not significantly different between septic and nonseptic critically ill patients during the administration of standardized total parenteral nutrition. A disease-specific macronutrient composition of total parenteral nutrition formulas does not seem to be necessary in either septic or nonseptic critically ill patients.