Appendix 1.

Definitions of complications

Complications	Requirement
Major complications
Anastomotic leakage	A defect of the intestinal wall at the anastomotic site leading to a communication between the intra- and extra-luminal compartments.
Peritonitis	Infection or inflammation of the peritoneum caused by intestinal perforation, trauma, postoperative infection from drains, or direct spread of infected organ.
Re-operation	Need re-surgery to repair because of postoperative anastomotic fistula and other problems.
Pneumonia	The presence of new and/or progressive pulmonary infiltrates on chest radiograph plus two or more of the following:
	● fever of 38.5°C or higher, or postoperative hypothermia less than 36°C;
	● leukocytosis of 10,000 white blood cell/mm3 or greater or leukopenia less than 4,000 white blood cell/mm3;
	● purulent sputum; and/or;
	● new onset or worsening cough or dyspnea.
Deep venous thrombosis	Venous reflux disorder caused by abnormal coagulation of blood in deep veins.
Arrhythmia	Electrocardiograph evidence of cardiac rhythm disturbance.
Stroke	Embolic, thrombotic, or hemorrhagic cerebrovascular event with persistent motor, sensory, or cognitive dysfunction confirmed by computerized tomography, magnetic resonance imaging, or autopsy.
Mortality	Patient death after primary surgery.
Minor Complications
Urinary and other infection	Local inflammatory signs and specific antibiotic treatment.
Wound bleeding	Postoperative wound dehiscence or bleeding requiring drug treatment.
Postoperative nausea and vomiting	Nausea or vomiting within 24 to 48 h of surgery and requiring antiemetic therapy.
Cough and expectoration	Did not meet the diagnostic criteria for pneumonia.
Impaired liver function	Aspartate aminotransferase, alanine aminotransferase greater than 2 times normal value.
Pruritus	Severe itching of the skin.