The Serum Citrulline and D-Lactate are Associated with Gastrointestinal Dysfunction and Failure in Critically Ill Patients

OBJECTIVE: This study attempted to screen and combine effective biomarkers to analyse the association between these biomarkers and gastrointestinal failure (GIF) in critically ill patients. METHODS: A total of 110 critically ill patients with acute gastrointestinal injury (AGI) admitted to ICU were enrolled. The AGI grade was determined by the AGI classification proposed by ESICM. There were 67 patients in gastrointestinal dysfunction (GID) group (AGI grade II), 43 patients in GIF group (AGI grade III–IV), and 41 healthy adults in healthy control (HC) group. APACHE II and SOFA score were used to evaluate the disease severity. Peripheral blood samples of patients were collected within 24 hours of admission to the ICU (prior-treatment) and after the conventional medication therapy for 7 consecutive days (post-treatment). Citrulline serum level was detected by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method, and D-lactate and lipopolysaccharide (LPS) serum levels were measured by ELISA. Pearson correlation, logistic regression, and ROC curve analysis were used. RESULTS: Patients with GID or GIF had lower serum level of citrulline, while higher levels of D-lactate and LPS than HC. Compared with GID patients, serum level of citrulline was reduced, while D-lactate and LPS were elevated in GIF patients. Correlation analysis displayed that serum levels of citrulline, D-lactate, and LPS were associated with the APACHE II and SOFA score in patients with GID or GIF. Logistics regression analysis showed that citrulline and D-lactate were risk for both GID and GIF. ROC curve analysis exhibited that combination of citrulline and D-lactate had relatively high value to distinguish GID from HC, GIF from GID, and GIF from HC. CONCLUSION: Serum citrulline and D-lactate were associated with severity of GIF, combination of citrulline and D-lactate improved the diagnostic efficacy to identify GIF in critically ill patients.