Methods	Regional anaesthesia added to general anaesthesia versus general anaesthesia
Participants	1015 males undergoing abdominal aortic, open gastric, open biliary or open colon surgery
Interventions	General anaesthesia with thiopental, midazolam, fentanyl, nitrous oxide, isoflurane and vecuronium for all participants Thoracic or lumbar epidural anaesthesia (n = 514): 0.5% bupivacaine with epinephrine 5 mcg/mL for a sensory level ≧ T6, reinjected during the surgery and maintained as required for postoperative analgesia with morphine with/without local anaesthetics IV or IM opioids (n = 501)
Outcomes	Mortality: participant who died within 30 days after operation Myocardial infarction: an increase in serum concentration of the myocardial‐specific isoenzyme fractions of creatine kinase (CK‐MB) and lactic dehydrogenase, as evidenced by a ratio of CK‐MB/CPK of 5% or more AND/OR the following ECG changes: a typical new persistent elevation/depression of the ST segment and/or a new Q‐wave greater than 0.04 seconds in duration with its depth more than 25% of the amplitude of the succeeding R‐wave in limb leads, or any new Q‐wave in V1–V3. All study participants, in addition to the routine postoperative tests, had a 12‐lead electrocardiogram taken on the first and third postoperative days. Total creatine phosphokinase and MB isoenzymes were measured every 12 hours for three days after surgery Pneumonia: the presence of a new infiltrate on the chest x‐ray plus two of three clinical findings (a body temperature higher than 38°C, an abnormal elevation of white blood cell count and a pathogen identified in the sputum by Gram stain and culture), requiring intravenous antibiotic treatment
Notes	For participants undergoing abdominal aortic surgery, if frank blood was aspirated during the epidural procedure, the procedure was abandoned and rescheduled Heparin as required. Normal PT, PTT for epidural catheter removal. Antibiotics before surgery and for 24 hours after surgery