Gastric ultrasound, citrulline, and intestinal fatty acid–binding protein as markers of gastrointestinal dysfunction in critically ill patients: A pilot prospective cohort study

Abstract Background Gastrointestinal (GI) dysfunction is common in the intensive care unit (ICU), although there is no consensus on biomarkers of GI dysfunction. We aimed to evaluate ultrasound‐based gastric antrum measurements and serum intestinal fatty acid–binding protein (IFABP) and citrulline levels in relation to GI dysfunction in critically ill patients. Methods Adult critically ill patients receiving enteral nutrition and stayed for in the ICU for ≥48 h was included. GI dysfunction was described using Gastrointestinal Dysfunction Score (GIDS). Gastric antrum measurements, including craniocaudal (CC) diameter, anteroposterior diameter, and antral–cross sectional area (CSA), as well as serum levels for IFABP and citrulline, were prospectively recorded at baseline and on day 3 and day 5 of enteral nutrition. The receiver operating characteristic (ROC) analysis was performed to evaluate gastric ultrasound parameters, serum IFABP, and citrulline concentrations in predicting GI dysfunction. Results Thirty‐nine participants with a median age of 60 years were recruited and 46.2% of participants had GI dysfunction. ROC analysis revealed that the cutoff value of CSA score to predict GI dysfunction was 4.48 cm 2 , which provided 72.7% sensitivity and 77.2% specificity (area under the curve = 0.768, 95% CI: 0.555–0.980). At baseline, gastric residual volume was highly correlated with CC diameter and CSA ( r = 0.764, P < 0.001 and r = 0.675, P < 0.001, respectively). Serum IFABP and citrulline levels had no correlation with GI dysfunction or gastric ultrasound parameters ( P > 0.05). Conclusion CSA was associated with GI dysfunction in critically ill patients. Serum IFABP and citrulline concentrations were poor in predicting GI dysfunction.