Inclusion Criteria:  treatment by pancreatic resection, including pancreaticoduodenectomy, pancreatosplenectomy, total pancreatectomy, and other variant operations; revival in the intensive care unit (ICU) with standard serum lactate elution treatments after surgery instead of the operation room or general ward; availability of complete preoperative, intraoperative, and postoperative data; the peak serum lactate level in 24 hours after surgery >3.250 mmol/L.  Exclusion Criteria:  a history of surgical treatment of any upper abdominal lesions before the current hospital admission; the minimum mean arterial pressure <65 mmHg during the operation; without written informed consents for the perioperative situation and related studies.