Enterocyte Injury and Acute Gastrointestinal Dysfunction in Critical Illness

This study is a prospective observational cohort study conducted in an adult intensive care unit. Biological samples and clinical data will be prospectively collected according to a pre-defined protocol, without any intervention other than standard treatment. Primary objective: To prospectively assess the association between serum and urinary I-FABP levels and the severity of acute gastrointestinal injury in critically ill patients. Secondary objectives: To investigate the relationship between serum and urinary I-FABP levels and clinical outcomes (including severe AGI and mortality); to explore whether the intestinal epithelial cell injury patterns reflected by serum and urinary I-FABP are associated with different sepsis subphenotypes; and to evaluate the impact of gastrointestinal surgery on I-FABP levels and its modifying effect on the association between I-FABP and AGI severity.