It's not the operating room that is risky for patients undergoing non-cardiac surgery; it is the recovery period as researchers have found that only 0.7 per cent of deaths in these patients occurred in the operation room, whereas 29 per cent of deaths occurred after discharge.

Published in the journal CMAJ, the study included patients at 28 centres in 14 countries. "Given that most deaths in adults undergoing non-cardiac surgery occur not in the operation room, but afterwards, efforts to improve post-surgical care in hospital and at home has substantial potential to reduce mortality," said study author PJ Devereaux from McMaster University.

The study, which included 40,004 adults aged 45 years or older in North and South America, Asia, Europe, Africa and Australia who underwent surgery between 2007 and 2013, found that 1.8 per cent died within 30 days of non cardiac surgery. According to the researchers, major bleeding, injury to the heart muscle and severe infection (sepsis) accounted for a large portion of deaths (45 per cent).

"Approximately 100 million adults aged 45 or older undergo non-cardiac surgery worldwide every year, therefore an estimated 1.8 million people die of complications within 30 days, this means that death after surgery is a major global health burden," Devereaux said. The authors suggest that solutions focused on prevention, early identification and close management of bleeding, cardiac issues and infection may help to reduce these preventable deaths.

Data published are from the Vascular Events in Non-cardiac Surgery Patients Cohort Evaluation (VISION) study funded by more than 70 sources.