Table 2 Standard definitions of complications for assessing morbidity of trial patients

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