Table 2.

Standard definitions of complications for assessing morbidity of trial patients

Category	Definition
Cardiorespiratory	Respiratory failure - requiring mechanical ventilation
	Cardiac failure: cardiac index < 2 litres per m2 (treated first by fluid resuscitation and if no response by inotropic or vasoconstrictive medication)
	Pulmonary oedema - radiological diagnosis
	Arrhythmia - ECG changes requiring medical treatment and/or electroconversion
	Pleural fluid - radiographic diagnosis
	Acute myocardial infarction - electrocardiographic diagnosis
	Acute renal failure - requiring haemofiltration
	Stroke with neurological symptoms
	Pulmonary embolism
	Distal ischaemia
	Deep vein thrombosis - requiring duplex, radiological or other confirmation
	Other cardiorespiratory
Surgical	Unexpected blood loss >0.5 litres during operation
	Bowel perforation
	Ureteric damage
	Wound dehiscence involving separation of deep abdominal wall closure
	Postoperative bleeding - overt blood loss requiring > 2 litre transfusion with a normal clotting profile.
	Delayed oral intake - intravenous fluids > 1 week owing to postoperative ileus
	Bowel obstruction requiring reoperation
	Anastomotic leakage defined within 30 days of surgery radiologically (demonstration on abdominal CT with oral contrast, MRI or by contrast enema), surgically (visual evidence of faecal leakage at reoperation) or at autopsy (presence of a disrupted anastomosis).
	Necrosis of stoma - requiring surgery
	Aspiration Pneumonia - radiological diagnosis with appropriate history
	Other surgical
Infective	Sepsis - pyrexia > 38 oC, septic focus or positive blood culture
	Postoperative peritonitis - clinical diagnosis
	Abdominal abscess - ultrasonograpy, computed tomography or operative diagnosis
	Necrotising fasciitis
	Wound infection - defined as any one of the following: (modified from reference 26)
	1. Purulent discharge or the aspiration of pus
	2. Erythema or localised swelling requiring antibiotics or surgical drainage, unless the drainage is clear and negative on culture i.e. a seroma
	3. A diagnosis of a wound infection made by a doctor.
	4. Report of wound discharge by the patient unless it is proven to be uninfected
	Chest infection - radiological diagnosis or empyema
	Urinary tract infection
	Disseminated intravascular coagulation
	Other infective complication

Major morbidity is defined as any of the following occuring within the hospital admission or 30 days of surgery: haemorrhage (requiring transfusion), any re-operation or readmission, anastomotic leakage, wound dehiscence, sepsis requiring at least high dependency support, HDU stay of > 5 days, unplanned admission to Intensive or Coronary Care Unit and death.