Purpose of review: To update the documentation concerning the clinical use of glutamine supplementation in critically ill patients. Outcome, patient safety and future plans are examined.
Recent findings: In terms of outcome studies, the last 2 years have added little to our knowledge. A number of multi-centre studies are under way, however, which can be expected to give better evidence for the use of glutamine in the near future. In terms of patient safety, several new studies have demonstrated metabolic tolerance, vascular tolerance, losses in conjunction with continuous renal replacement therapy and the relation to intracerebral glutamate in head trauma. Glutamine losses in continuous renal replacement therapy are not negligible, and are actually a further argument for exogenous glutamine supplementation. Losses of supplemented glutamine into the dialysate are not a problem.
Summary: The use of intravenous glutamine supplementation in critically ill patients on total parenteral nutrition is currently the standard of care. The use of exogenous glutamine supplementation in critically ill patients on enteral nutrition is still not supported by sufficient evidence. The use of plasma glutamine concentration as an indicator for glutamine deficiency and a possible indicator for supplementation is suggested.