Plasma citrulline kinetics and prognostic value in the critically ill patient

Introduction

Multiple organ failure (MOF) is a frequent cause of death in the critically ill patient. The gut could be the cornerstone of MOF, the first step being an early splanchnic ischemia, inducing the loss of barrier function, systemic infections and MOF [1]. Plasma citrulline (normal 20 to 60 μmol/l) reflects a small bowel mass and is decreased in various small bowel diseases [2]. The objectives of the study were to study plasma citrulline kinetics and their prognostic value in adults hospitalized in the ICU.

Methods

A prospective monocentric observational study, including adults consecutively admitted to the ICU without small bowel disease, and without chronic renal failure. We studied at onset, hour 12, hour 24, day 2, and day 7 of plasma citrulline, and clinical, biological, prognostic and therapeutic parameters. The univariate analysis of plasma citrulline (0 to 10 μmol/l, 11 to 20 μmol/l, and >20 μmol/l) with other variables and multivariate analysis.

Results

Sixty-seven patients were included, mean age 60 years, organ dysfunctions and/or infections model ODIN score of 2.4, IGS2 score (Simplified Acute Physiology Score) of 50, and a 28-day mortality of 34%. During the first day, mean plasma citrulline decreased from 18.8 to 13.5 μmol/l, and it decreased more in nonsurvivors than in survivors among patients without acute renal failure (37% vs. 18%). A lower plasma citrulline at hour 24 was associated with higher plasma C-reactive protein, nosocomial infection rate, and 28-day mortality (P = 0.006, P = 0.03 and P = 0.03). A lower plasma citrulline at day 2 was associated with a higher use of catecholamines, and a lower use of enteral feeding (P = 0.02 and P = 0.01). In multivariate analysis, plasma citrulline at hour 24 and ODIN score at admission ≥ 3 were associated with 28-day mortality (P = 0.04 and P = 0.04).

Conclusion

A lower plasma citrulline at hour 24 was associated with higher plasma C-reactive protein, nosocomial infection rate, and 28-day mortality. A lower plasma citrulline at day 2 was associated with a higher use of catecholamines, and a lower use of enteral feeding. Such results could reflect the systemic consequences of acute intestinal failure in patients hospitalized in the ICU.