Glutaminemia prognostic significance in critical surgical patients - An analysis of plasma aminogram profile.

BACKGROUND: Glutamine depletion is common in the critically-ill patients. Glutaminemia lower than 420 μmol/l has been considered as an independent predictive factor of mortality, but the indications for exogenous glutamine supplementation remain controversial. This study intends to determine the glutaminemia profile in critical surgical patients and to investigate its correlation with the severity indexes and the prognosis.

METHODS: A prospective study of 28 adult critical surgical patients was performed. Plasma amino acid concentrations were quantified, by ion exchange chromatography, at the moment of admission and at the first and third days, and compared with those of 11 reference healthy individuals. Severity indexes and parameters of prognosis were registered.

RESULTS: In critical surgical patients, mean glutaminemia at admission was lower than that of control individuals (385.1 ± 123.1 versus515 ± 57.9 μmol/l, p = 0.002) and decreased until the third day (p = 0.042). Prevalence of severe hypoglutaminemia (< 420 μmol/l) at admission was 64.3%. Baseline glutaminemia correlated with the Simplified Acute Physiology Score II (SAPS II score) (Pearson's correlation coefficient r = -39.4%, p = 0.042), and it was lower in cases of erythrocytes transfusion (339.9 ± 78.8 versus 454.9 ± 148.8 μmol/l, p = 0.013). Glutaminemia at the third day correlated with the duration of invasive ventilation support (r = -65%, p = 0 .012) and ICU stay (r = -66.5%, p = 0.009). Glutaminemia below 320 μmol/l, observed in 25% of the patients, was associated with higher in-hospital mortality (42.9 versus19%, statistically not significant [n.s.]) and lower actuarial survival (212.1 ± 77.9 versus 262.3 ± 32.4 days, n.s.).

CONCLUSIONS: Those results underscore the relevance of hypoglutaminemia as an adverse predictive factor in the critical surgical patients. Determination of glutaminemia may contribute to a better definition of the indications for glutamine supplementation.