The purpose is to correct water and electrolyte disorders, support treatment, and prevent local and systemic complications. The content includes: routine blood measurement, routine urine measurement, fecal occult blood measurement, renal function measurement, liver function measurement; blood glucose measurement; cardiac monitoring; blood pressure monitoring; blood gas analysis; serum electrolyte measurement; chest X-ray; central venous pressure measurement. Dynamic observation of abdominal signs and bowel sound changes. The 24-h urine output and volume changes were recorded. The above indicators can be selected according to the patient’s specific condition. Routine fasting, gastrointestinal decompression should be performed for those with severe abdominal distension and paralytic intestinal obstruction. Open diet can be considered when the patient’s abdominal pain is reduced/resolved, abdominal distension is reduced/resolved, and intestinal motility is restored/or partially restored, starting with carbohydrate-based diet and gradually transitioning to low-fat diet, without taking the high or low serum amylase activity as a necessary condition for open diet.