By: 19 January 2021
The Ottawa Hospital study shows benefits of spinal or epidural anaesthesia over general anaesthesia for leg artery bypass surgery

A new study by researchers at The Ottawa Hospital and published in The BMJ shows that people who had surgery to improve blood flow in their legs under spinal or epidural anaesthesia were less likely to die than those who were given general anaesthesia.

General anaesthesia involves using drugs to make a patient unconscious and inserting a tube into their windpipe to help with breathing. Spinal and epidural anaesthesia directly freeze the nerves to the legs and can be combined with lighter forms of sedation which do not involve a breathing tube.

This study, the largest of its kind, looked at medical records of 20,988 people who had leg artery bypass surgery in Ontario, Canada, between 2002 and 2015. Approximately two thirds of these surgeries used general anaesthesia and a third used spinal or epidural anaesthesia.

The researchers found that 646 of the patients who had general anaesthesia (4.4 percent) died within 30 days of their surgery compared to 204 of the patients who had spinal or epidural anaesthesia (3.2 percent). The results remained the same after the researchers adjusted for differences between the groups, such as how sick the patients were before surgery.

Lead author Dr Derek Roberts, a vascular and endovascular surgeon at The Ottawa Hospital and incoming assistant professor at the University of Ottawa, said: “We estimate that this finding could save at least 100 of the patients’ lives who undergo leg artery bypass surgeries every year both in Canada and the United States.

We hope to conduct a randomised controlled trial to confirm these results, but in the meantime our findings suggest that we should increasingly perform more of these types of surgeries using spinal or epidural anaesthesia techniques.”

Senior author Dr Daniel McIsaac, associate scientist and anesthesiologist at The Ottawa Hospital, associate professor at the University of Ottawa, and adjunct scientist at ICES, said: “We were surprised to find that some hospitals did these types of surgeries under spinal or epidural anaesthesia more than 90 percent of the time, while in others it was less than one percent.

We hope this study will help patients and physicians make more informed decisions about what type of anaesthetic is best for each patient.”

The study also found that patients who had spinal or epidural anaesthesia were able to leave the hospital half a day earlier than those who had general anaesthesia.

The researchers estimate that if all leg artery bypass surgeries were done with spinal or epidural anaesthesia, it could save $50 million in healthcare costs each year in Canada. In Ontario, the vast majority of these surgeries are done in specialty centres that can easily perform spinal or epidural anaesthesia.

Close to 20,000 people have leg artery bypass surgery in Canada and the US every year.

Source: The Ottawa Hospital