Plasma glutamine depletion and patient outcome in acute ICU admissions.

Abstract

To evaluate whether low plasma glutamine (PG) is related to severity of illness, and actual and predicted hospital mortality. Prospective cohort study. 18-bed closed format general intensive care unit (ICU) of a teaching hospital. Cohort of 80 seriously ill patients non-electively admitted to the ICU. Blood sampling for the determination of PG at ICU admission. Severity of illness and predicted mortality were calculated using the locally validated APACHE II, SAPS II, and MPM II 0 and 24 systems. Illness scores, and actual and predicted hospital mortality were compared between patients with total PG < 0.420 mmol/l ("low PG") and patients with PG > or = 0.420 mmol/l. Mean total PG was 0.523 mmol/l, range 0.220-1.780 mmol/l. Low PG (n = 25) was associated with higher age (P = 0.03), shock as primary diagnosis, and higher actual hospital mortality (60 % vs 29 %, P = 0.01). Normal to high PG was associated with high plasma creatine phosphokinase (P = 0.007) There was a nonsignificant trend towards higher severity of illness scores and predicted mortality rates in the low PG group. The presence of low PG significantly improved mortality prediction when added as a factor to the APACHE II predicted mortality rate (P = 0.02). Low PG at acute ICU admission is related to higher age, shock as primary diagnosis, and higher hospital mortality. Low PG represents a risk of poor outcome, not fully reflected in the presently used mortality prediction systems.