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News Release: Sleep apnea patients can breathe easy

U of M study finds CPAP device can reduce risk of complications after anesthetics, surgery

September 23, 2014 — 

University of Manitoba-led research has found, for the time, that the risk of serious postoperative cardiovascular complications after surgery could be reduced by more than half if patients with obstructive sleep apnea (OSA) were prescribed treatment with a continuous positive airway pressure (CPAP) device, before their operation.

The study, A Matched Cohort Study of Postoperative Outcomes in Obstructive Sleep Apnea: Could Preoperative Diagnosis and Treatment Prevent Complications,was published today in the October issue of the prestigious journal Anesthesiology, the official medical journal of the American Society of Anesthesiologists.

In light of these findings, appropriate testing for OSA and treatment with a CPAP device, should be considered before patients at risk for OSA undergo surgery, said principal investigator Dr. Thomas Mutter, assistant professor, department of anesthesia and perioperative medicine, College of Medicine, Faculty of Health Sciences, University of Manitoba..

Mutter’s team, along with co-author Dr. Meir Kryger, professor of pulmonary and sleep medicine, Yale School of Medicine, sought to determine what factors affect the risk of serious complications after surgery in patients with obstructive sleep apnea.

Researchers, using data from the U of M’s Manitoba Centre for Health Policy, compared postoperative outcomes in 4,211 patients diagnosed with OSA, with a matched control group of patients who did not have the condition.  Those who were diagnosed with OSA prior to surgery were treated with CPAP therapy.

“We found that patients with untreated OSA were at an increased risk of developing cardiovascular complications after surgery, like cardiac arrest and shock,” said Mutter. “However, OSA patients who were diagnosed and prescribed CPAPtherapy before surgery were less than half as likely to develop these same complications.  In fact, their risk was similar to patients without OSA.”

Furthermore, Mutter’s team found that serious respiratory and cardiovascular complications were increased about two-fold in OSA patients compared to patients without OSA. Increased severity of OSA as well as age, type of surgery and other chronic diseases were also important risk factors in complications.

Obstructive sleep apnea is a common disease, predominantly among men, where patients experience repetitive episodes of airway obstruction during sleep that lead to fragmented, unsatisfying sleep.  The main symptoms are loud snoring, pauses in breathing during sleep and excessive sleepiness during the day.

Untreated OSA can also have negative effects on long-term health. OSA is usually treated with a CPAP device, which can improve sleep quality and likely prevent long-term health issues. Diagnosis of OSA requires a sleep study.

Over the past 15 years, Mutter noted, there has been increasing concern that the deleterious effects of anesthetics and surgery on breathing and sleep could be especially risky for patients with obstructive sleep apnea.  “This has been of particular concern because as many as 25 per cent of patients presenting for surgery may have OSA.  Surprisingly, the vast majority of these patients aren’t treated with CPAP and may not even know they have OSA,” he said.  “This study gives us new, important insight as to when treating these patients with CPAP before their operation might make their surgery safer.”

This research was supported by the Manitoba Centre for Health Policy, the National Institutes for Health, and the University of Manitoba.


For more information contact Ilana Simon, Director of Communications & Marketing, Faculty of Medicine, University of Manitoba, 204-789-3427, (cell) 204-295-6777 or



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