Enteral Glutamine in Critical Illness
Randomized Clinical Trial Comparing Enteral Glutamine Supplementation to Standard of Care Enteral Feeding in Critical Illness
Glutamine is an amino acid which is rapidly depleted in critical illness. It is used as
energy by cells that line the gut, vital for immune system function, and works as an
anti-oxidant. Glutamine supplementation has been shown to improve outcomes in ICU patients.
We hypothesize that critically ill patients given extra glutamine will have less of an
inflammatory response and therefore better outcomes than patients not given extra glutamine.
Our study randomizes patients to tube feeding with OR without extra glutamine to see if it
affects patient outcomes as well as markers of inflammation.
Glutamine, a nonessential amino acid, is preferred fuel for rapidly proliferating cells in
human body. Those cells include the enterocytes in small intestine, lymphocytes,
macrophages, and fibroblasts. Glutamine also transports nitrogen between tissues and serves
as a precursor to glutathione which is a potent antioxidant. A healthy human body contains
abundant glutamine, either from diet or from skeletal muscle tissue that synthesizes it.
During critical illness the demand for glutamine is increased. Rapid depletion of glutamine
stores in critically ill patients has been described and correlated to increased mortality.
Glutamine depletion may be deleterious in critical illness because of adverse effects on the
essential functions mentioned above. For example glutamine depletion may cause gut mucosal
barrier function to deteriorate, leading to bacterial translocation and enhanced systemic
inflammatory response with increased risk for multisystem organ failure. Clinical trials
performed in a wide range of patients with serious illness, including cancer, trauma, burn,
major surgery and critical illness, have demonstrated possible benefits of glutamine
supplementation. Interpretation of the results of multiple studies is made difficult based
on differences in glutamine dosing, route of administration, population studied, and
Blood volume analysis has been shown to be a good measure of capillary leak. The DAXOR blood
volume analyzer kit was recently approved by the FDA for blood volume analyses and also has
the capacity of measuring capillary permeability by looking at the slope of albumin
transudation. It is a simpler way to measure capillary permeability than other methods
Reviewing the previous study results, glutamine supplementation in parental form and with
higher dose in various patient populations has shown evidence of being beneficial. Studies
of enteral glutamine therapy have also showed benefits, but results are less consistent
possibly because of the heterogeneous study methodology described above. Moreover, most of
the studies are carried out in burn patients and surgical patients; there were few studies
in critical ill medical patients. Finally no study has specifically looked at the mechanism
via which glutamine has conferred protection.
Comparison: Critically ill patients given enteral tube feeds compared to critically ill
patients given enteral tube feeds with supplemental glutamine.
Critical Illness, Sepsis, Respiratory Insufficiency
Glutamine, Critical Illness, Enteral Feeding, Blood Volume Analysis
Christiana Care Health Services
Christiana Care Health Services
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