Thermogenic response to intravenous nutrition in patients with cirrhosis

Energy expenditure was determined using continuous indirect calorimetry in the basal state and during 3 h of total parenteral nutrition (TPN) in 8 patients with cirrhosis and 8 healthy volunteers. TPN consisted of glucose, fat and amino acids and had a glucose/fat ratio of 50:50. The infusion rate was set to provide energy corresponding to 62.5% of the individually measured 24-h resting energy expenditure. In the basal state energy expenditure was similar in patients and controls while the respiratory quotient (RQ) was lower in the patients (0.78 +/- 0.01 vs. 0.82 +/- 0.01, mean +/- SEM, p < 0.05). During TPN, energy expenditure increased progressively during the 3-h infusion period. The average rise in energy expenditure was similar in patients (19.1 +/- 1.2%) and in controls (21.4 +/- 1.6%, n.s.). The RQ rose in both groups, but more in the patients with cirrhosis. At the end of the study, RQ was higher in patients (0.89 +/- 0.01) than in controls (0.85 +/- 0.01, p < 0.05). It is concluded that the nutrient-induced rise in energy expenditure during TPN is not significantly different in patients with cirrhosis and control subjects. Furthermore, the results indicate that the increased fat utilization in overnight fasting cirrhotic patients is rapidly shifted to an augmented carbohydrate oxidation during TPN, possibly as a consequence of marked hyperinsulinemia.