Parenteral glutamine supplementation in critical illness: a systematic review.

Paul E Wischmeyer,Rupinder Dhaliwal,Thomas R Ziegler,Daren K Heyland,Michele Mccall

doi:10.1186/cc13836

Abstract

IntroductionThe potential benefit of parenteral glutamine (GLN) supplementation has been one of the most commonly studied nutritional interventions in the critical care setting. The aim of this systematic review was to incorporate recent trials of traditional parenteral GLN supplementation in critical illness with previously existing data.MethodsAll randomized controlled trials of parenterally administered GLN in critically ill patients conducted from 1997 to 2013 were identified. Studies of enteral GLN only or combined enteral/parenteral GLN were excluded. Methodological quality of studies was scored and data was abstracted by independent reviewers.ResultsA total of 26 studies involving 2,484 patients examining only parenteral GLN supplementation of nutrition support were identified in ICU patients. Parenteral GLN supplementation was associated with a trend towards a reduction of overall mortality (relative risk (RR) 0.88, 95% confidence interval (CI) 0.75, 1.03, P = 0.10) and a significant reduction in hospital mortality (RR 0.68, 95% CI 0.51, 0.90, P = 0.008). In addition, parenteral GLN was associated with a strong trend towards a reduction in infectious complications (RR 0.86, 95% CI 0.73, 1.02, P = 0.09) and ICU length of stay (LOS) (WMD –1.91, (95% CI -4.10, 0.28, P = 0.09) and significant reduction in hospital LOS (WMD -2.56, 95% CI -4.71, -0.42, P = 0.02). In the subset of studies examining patients receiving parenteral nutrition (PN), parenteral GLN supplementation was associated with a trend towards reduced overall mortality (RR 0.84, 95% CI 0.71, 1.01, P = 0.07).ConclusionsParenteral GLN supplementation given in conjunction with nutrition support continues to be associated with a significant reduction in hospital mortality and hospital LOS. Parenteral GLN supplementation as a component of nutrition support should continue to be considered to improve outcomes in critically ill patients.

Highlights

The potential benefit of parenteral glutamine (GLN) supplementation has been one of the most commonly studied nutritional interventions in the critical care setting
Clinical trials from the past 20 years demonstrated that GLN appears to reduce mortality, infectious complications, and intensive care unit (ICU)/hospital length of stay (LOS) [1]. Most of these previous trials were conducted in a select group of patients with the following characteristics: 1) predominantly receiving complete nutrition support via parenteral nutrition (PN), 2) common exclusion of renal and liver failure based on glutamine product prescribing restrictions, 3) GLN supplementation of PN is often initiated later in the ICU stay, as PN is typically started later in the stay when enteral nutrition (EN) is not possible or meeting nutritional needs, 4) enrollment of oncology patients who may be at a greater risk for tumor-mediated GLN depletion, 5) use of GLN dose between 0.3 g/kg/day to a maximum of 0.5 g.kg/day given only via the intravenous route
Meta-analyses of primary and secondary outcomes Effect of GLN supplementation on mortality When the 24 studies that reported on mortality (Figure 1) were aggregated, IV GLN supplementation was associated with a trend towards a reduction in overall mortality (RR 0.88, 95% confidence interval (CI) 0.75, 1.03, P = 0.10, heterogeneity I2 = 0%)

Summary

Introduction

The potential benefit of parenteral glutamine (GLN) supplementation has been one of the most commonly studied nutritional interventions in the critical care setting. ICU/hospital length of stay (LOS) [1] Most of these previous trials were conducted in a select group of patients with the following characteristics: 1) predominantly receiving complete nutrition support via PN, 2) common exclusion of renal and liver failure based on glutamine product prescribing restrictions, 3) GLN supplementation of PN is often initiated later in the ICU stay (not at ICU admission during the shock phase), as PN is typically started later in the stay when enteral nutrition (EN) is not possible or meeting nutritional needs, 4) enrollment of oncology patients who may be at a greater risk for tumor-mediated GLN depletion, 5) use of GLN dose between 0.3 g/kg/day to a maximum of 0.5 g.kg/day given only via the intravenous route. This is summarized below: Characteristics of traditional parenteral glutaminesupplementation trials

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Results

Discussion

Conclusion