Longitudinal pattern of glutamine/glutamate balance across the leg in long-stay intensive care unit patients

Background & Aims: Progressive muscle wasting is a characteristic feature of patients treated at the intensive care unit (ICU). As a consequence, endogenous glutamine production by skeletal muscle may be compromised. We investigated the time pattern of the glutamine and glutamate net balance across the leg in long-stay ICU patients. Methods: Critically ill patients with multiple organ failure that were expected to stay in the ICU for more than 3 days were included in a longitudinal study. Possible changes in amino acid net balance over the leg muscle were investigated overtime. The patients (n=20) were studied descriptively every third or fourth day, on a total of 2-7 occasions. Main results: The glutamine net release from leg muscles did not change significantly during the initial 2 weeks of ICU stay and was not related to the plasma concentration of glutamine. The net uptake of glutamate across the leg muscles was unaltered during this time period, but it was found to correlate statistically with both the arterial glutamate concentration and the glutamine net release. A continuous net release of phenylalanine indicated a progressive net loss of muscle protein in these patients. Conclusion: The net release of glutamine from skeletal muscle does not decrease in stabilized critically ill patients with multiple organ failure over the initial 2 weeks of ICU stay, despite progressive muscle wasting. (C) 2002 Published by Elsevier Science Ltd.