Comparison of protein absorption efficiency between peptide and whole protein enteral nutrition preparations in high-risk groups with pancreatic exocrine insufficiency in the ICU

INTERVENTION: Proteomic group:Nutritional support therapy was administered with protein‐type EN preparations;Short peptide group:Short peptide EN preparations were administered for nutritional support; CONDITION: Pancreatic Exocrine Insufficiency, PEI PRIMARY OUTCOME: Citrulline concentration;Branched‐chain amino acid concentration; SECONDARY OUTCOME: Fecal elastase‐1; INCLUSION CRITERIA: 1. Age >= 18 years, any gender, able to meet the time requirements for baseline data collection and intervention implementation; 2. Meets the definition of high‐risk PEI population and fulfills any of the following conditions: (1) APACHE II score >= 15, indicating severe condition, obvious stress response, and higher risk of pancreatic dysfunction; (2) Post major abdominal surgery (including gastrointestinal, hepatobiliary, pancreatic surgeries), within 7 days after surgery, during the postoperative stress period, when pancreatic function is easily affected by surgical trauma; (3) Complicated with severe acute pancreatitis, meeting diagnostic criteria according to the Atlanta classification (2012 version); (4) Diagnosed with sepsis (SOFA score >= 2) with elevated serum pancreatic lipase/amylase levels (exceeding 1.5 times the upper limit of normal), indicating pancreatic involvement; (5) Long‐term fasting (>= 72 hours) accompanied by gastroint