This study aims to explore the correlation between gastrointestinal blood flow and the incidence of enteral nutrition intolerance (ENI) and its symptoms in critically ill patients, construct and compare predictive models including blood flow parameters, and evaluate their incremental predictive value.
Age > 18 years old.
Expected duration of enteral nutrition support > 7 days.
Patients or their legal representatives sign the informed consent form.
History of major gastrointestinal surgery such as subtotal gastrectomy and gastrointestinal anastomosis.
Contraindications to abdominal point-of-care ultrasound (POCUS) examination (e.g., recent large-area abdominal burns, dressings blocking movement, open abdomen).
Presence of severe gastrointestinal diseases such as gastroparesis, intestinal obstruction, digestive tract perforation, and gastrointestinal bleeding upon admission.
Presence of severe peripheral vascular disease or valvular heart disease.