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 × min^–1 × m^–2, respectively). Energy balances were positive for both groups on days 2 (0.68 ± 0.4 and 0.74 ± 0.6 kJ × min^–1 × m^–2, respectively; NS) and 7 (0.65 ± 0.3 and 0.78 ± 0.5 kJ × min^–1× 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.