Plasma glutamine concentration after intensive care unit discharge: an observational study

Critical Care, Dec 2014

Introduction Low plasma glutamine concentration at ICU admission is associated with unfavorable outcomes. The prediction of plasma glutamine concentration after ICU discharge on outcomes has not been characterized. In the recent Scandinavian Glutamine Trial, a survival advantage was seen with glutamine supplementation as long as patients stayed in the ICU. It was therefore hypothesized that the glutamine level may drop at ICU discharge, indicative of a sustained glutamine deficiency, which may be related to outcome. Methods Fully fed ICU patients intravenously supplemented with glutamine for >3 days were studied at ICU discharge and post ICU. In study A, plasma glutamine level was followed every 5 to 7 days post ICU of the remaining hospital stay and compared to the level on the day of ICU discharge (n = 63). In study B, plasma glutamine level 24 to 72 hours after ICU discharge was related to 12-month all-cause mortality (n = 100). Results Post-ICU plasma glutamine levels were within normal range and were not found to be predictive for mortality outcome. Plasma glutamine level at discharge, on the other hand, was within normal limits but higher in nonsurvivors. In addition, it was adding prediction value to discharge SOFA scores for post-ICU mortality. Conclusions Post-ICU glutamine levels are not indicative of glutamine depletion. The relation between plasma glutamine concentration and glutamine availability during critical illness is not well understood, and needs to be studied further to define the possible role for glutamine supplementation.

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Plasma glutamine concentration after intensive care unit discharge: an observational study

Smedberg et al. Critical Care Plasma glutamine concentration after intensive care unit discharge: an observational study Marie Smedberg 0 Johanna Nordmark Grass 0 Linn Pettersson 0 ke Norberg 0 Olav Rooyackers 0 Jan Wernerman 0 0 Department of Anesthesiology and Intensive Care Medicine, K32, Karolinska University Hospital Huddinge , 141 86 Stockholm , Sweden Introduction: Low plasma glutamine concentration at ICU admission is associated with unfavorable outcomes. The prediction of plasma glutamine concentration after ICU discharge on outcomes has not been characterized. In the recent Scandinavian Glutamine Trial, a survival advantage was seen with glutamine supplementation as long as patients stayed in the ICU. It was therefore hypothesized that the glutamine level may drop at ICU discharge, indicative of a sustained glutamine deficiency, which may be related to outcome. Methods: Fully fed ICU patients intravenously supplemented with glutamine for >3 days were studied at ICU discharge and post ICU. In study A, plasma glutamine level was followed every 5 to 7 days post ICU of the remaining hospital stay and compared to the level on the day of ICU discharge (n = 63). In study B, plasma glutamine level 24 to 72 hours after ICU discharge was related to 12-month all-cause mortality (n = 100). Results: Post-ICU plasma glutamine levels were within normal range and were not found to be predictive for mortality outcome. Plasma glutamine level at discharge, on the other hand, was within normal limits but higher in nonsurvivors. In addition, it was adding prediction value to discharge SOFA scores for post-ICU mortality. Conclusions: Post-ICU glutamine levels are not indicative of glutamine depletion. The relation between plasma glutamine concentration and glutamine availability during critical illness is not well understood, and needs to be studied further to define the possible role for glutamine supplementation. - Introduction A low plasma concentration of glutamine at intensive care unit (ICU) admission is associated with an unfavorable outcome [1,2]. A high glutamine concentration at ICU admission may also communicate a negative prediction [2]. Other reports claim that free glutamine depletion in tissues (during ICU stays) is associated with unfavorable outcome [3,4]. So the hypothesis - that at least some critically ill patients may have a shortage of free glutamine - seems to be valid. Conventional products for enteral feeding of critically ill patients contain the same amounts of glutamine as ordinary food, while conventional products for parenteral feeding of these patients do not contain any glutamine, related to stability issues. Consequently, supplementation of glutamine was suggested [5]. Literature on glutamine supplementation for critically ill patients is extensive. Meta-analyses suggest a beneficial effect when intravenous (iv) supplementation is given to ICU patients on parenteral nutrition [6,7]. Reports on enteral supplementation to ICU patients on enteral nutrition are less conclusive [6]. Only a few studies include plasma glutamine concentration measurements as a possible indicator of individuals with glutamine depletion, which should be the proper target group for supplementation [8-10]. The rational for supplementing critically ill patients - without knowledge of their actual glutamine status - has been that glutamine supplementation was considered to be without side effects [5,11]. But recently, a study demonstrated harm when supplying glutamine in high doses as a part of a pharmaconutrition concept in the acute phase of critical illness [9], although the subjects were a selected subgroup that received hypocaloric nutrition and had two or more organ failures. So better knowledge of the glutamine status and whether or not an actual deficiency of glutamine is present in the individual patient is needed. The Scandinavian Glutamine Trial indicated in secondary outcomes of only patients treated per protocol that iv glutamine supplementation may improve outcome during ICU stay [12]. This possible benefit, however, was not sustained after ICU discharge, which may be related to that glutamine supplementation was discontinued at discharge. To elucidate this hypothesis two observational research studies were launched: Study A - to follow plasma glutamine concentrations after ICU discharge, and Study B - to find out if post-ICU plasma glutamine concentration is a mortality predictor. Methods Patients The unit has 12 beds and is the only ICU at the Huddinge wing of Karolinska University Hospital, which includes transplant surgery, major gastrointestinal surgery, hematology and infectious diseases, but not cardiac surgery, trauma care and neurosurgery. The protocol was to include consecutive patients admitted to the general ICU at Karolinska University Hospital Huddinge, who received iv glutamine supplement for >3 days. Exclusion criteria were: age <18, restrains of treatment, absence of informed co (...truncated)


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Marie Smedberg, Johanna Grass, Linn Pettersson, Åke Norberg, Olav Rooyackers, Jan Wernerman. Plasma glutamine concentration after intensive care unit discharge: an observational study, Critical Care, 2014, pp. 677, 18, DOI: 10.1186/s13054-014-0677-8