Thermogenic, hormonal and metabolic effects of intravenous glucose infusion in human sepsis

Background Sepsis is associated with alterations in glucose metabolism and the effect of intravenous feeding on energy expenditure is unclear. Many studies of glucose metabolism in humans with sepsis have employed techniques that are not relevant to the practice of intravenous feeding. Methods The thermogenic, hormonal and metabolic effects of glucose were evaluated in a prospective experimental study of septic (n = 6) and non-septic (n = 6) subjects, by administering glucose intravenously under conditions and at a rate similar to those used in total parenteral nutrition. Results Patients with sepsis had a higher fasting metabolic rate than control subjects (P<0.001) and a lower fasting respiratory quotient (P<0.03). The thermic effect of glucose in both groups was small and not statistically significant (median 3.2 and 0.4 per cent in septic and non-septic subjects respectively, P>0.1). Patients with sepsis had an attenuated plasma insulin response to glucose administration compared with control subjects (P < 0.001) and less marked suppression of plasma fatty acid and glycerol concentrations (P < 0.001). Glucose administration was not associated with significant changes in plasma catecholamine concentrations in either group of patients. Conclusion Intravenous infusion of glucose at clinically relevant rates is associated with a negligible thermogenic response, with no activation of the sympathetic nervous system.