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

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 cm² , 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.