Effects on skeletal muscle of intravenous glutamine supplementation to ICU patients

Objective: To evaluate the effect of four doses of intravenous glutamine supplementation on skeletal muscle metabolism. Design: A prospective, blinded, randomized study. Setting: The general Intensive Care Unit (ICU) of a university hospital. Patients: ICU patients with multiple organ failure (n=40), who were expected to stay in the unit for more than five days. Intervention: Patients received 0, 0.28, 0.57 or 0.86 g of glutamine per kg bodyweight per day intravenously for five days as part of an isocaloric, isonitrogenous and isovolumetric diet. Results: Plasma glutamine concentration responded to glutamine supplementation with normalization of plasma levels in a dose-dependent way, while free muscle glutamine concentration, as well as muscle protein synthesis and muscle protein content, did not change significantly. Conclusion: Intravenous glutamine supplementation to ICU patients for a period of five days resulted in normalization of plasma glutamine concentrations in a dose-dependent way whereas muscle glutamine concentrations were unaffected.