Plasma glutamine depletion and patient outcome in acute ICU admissions

Objective: To evaluate whether low plasma glutamine (PG) is related to seve rity of illness, and actual and predicted hospital mortality. Design: Prospective cohort study. Setting: 18-bed closed format general intensive care unit (ICU) of a teachi ng hospital. Patients: Cohort of 80 seriously ill patients non-electively admitted to th e ICU. Interventions: Blood sampling for the determination of PG at ICU admission. Measurements and results: 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 we re compared between patients with total PG < 0.420 mmol/l ("low PG") and pa tients with PG<greater than or equal to>0.420 mmol/l. Mean total PG was 0.5 23 mmol/l, range 0.220-1.780 mmol/l. Low PG (n = 25) was associated with hi gher 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 hi gh plasma creatine phosphokinase (P = 0.007) There was a nonsignificant tre nd towards higher severity of illness scores and predicted mortality rates in the low PG group. The presence of low PG significantly improved mortalit y prediction when added as a factor to the APACHE II predicted mortality ra te (P = 0.02). Conclusions: Low PG at acute ICU admission is related to higher age, shock as primary diagnosis, and higher hospital mortality. Low PG represents a ri sk of poor outcome, not fully reflected in the presently used mortality pre diction systems.