Comparing Early Enteral Nutrition Versus Parenteral Nutrition After Pancreaticoduodenectomy

Inclusion Criteria: * Age between 18 and 80 years old, gender is not limited; * All patients underwent pancreaticoduodenectomy; * ECOG 0 \~ 2 for physical condition score; * Imaging examination found pancreatic head, periampullary space, no distant metastasis and ascites; * No bone marrow dysfunction; * Those without obvious surgical contraindications; * Expected postoperative survival ≥3 months; * The study visit plan and other programme requirements are now available; * Voluntary participation and signing of informed consent. Exclusion Criteria: * Patients with stage II and IV periampullary carcinoma of head of pancreas and periampullary carcinoma; * Active infected persons; * Distant metastasis or ascites were found in imaging examination; * Patients with serious impairment of heart, liver and kidney function (grade 3 to 4, ALT and/or AST more than 3 times the normal upper limit, Cr more than the normal upper limit); * patients with other malignant tumors or blood diseases; * Pregnancy, planned pregnancy and lactation female patients (urine HCG \>02500 iu /L, diagnosed as early pregnancy);