St. Louis hospital screens surgery patients for sleep apnea

ST. LOUIS -- Carla Carr knew she felt tired a lot, but never suspected sleep apnea.

The Fort Gibson, Okla., woman said she never had a diagnosis, although she'd often be awakened by her husband when he'd catch her not breathing during sleep.

Carr, 43, was identified as being at high risk for obstructive sleep apnea (OSA) just before undergoing nine-hour surgery at Barnes-Jewish Hospital in February.

That knowledge helped ensure she had the proper safety mechanisms and monitoring in place during her hospital stay.

Barnes-Jewish Hospital began screening its surgery patients for obstructive sleep apnea -- something that hasn't been on hospitals' radar screen -- after a devastating complication in another surgery patient three years ago.

A healthy 40-year-old patient who had undergone successful surgery for a minor injury stopped breathing, went into a persistent vegetative state and eventually died. Doctors suspected he had an undiagnosed case of OSA.

"Most people think about the heart presurgery, but not sleep apnea affecting surgery," said Dr. Kevin Finkel, a Washington University anesthesiology resident at Barnes-Jewish.

Last year, the American Society of Anesthesiologists approved practice guidelines for managing surgery patients with OSA.

Obstructive sleep apnea is characterized by episodes of stopped breathing during sleep.

Normally, low levels of oxygen and high levels of carbon dioxide in the blood arouse the sleeper with apnea.

But an anesthetic, or powerful pain medicine after surgery may interfere with the protective mechanism and prevent the person from waking up, resulting in respiratory arrest, said Dr. Michael Avidan, Barnes-Jewish's division chief of cardiothoracic anesthesia and cardiothoracic intensive care.

The hospital set up a task force to identify surgical patients with sleep apnea and modify their care.

At the same time, a hospital research team studied the extent of sleep apnea in adult surgery patients. The team discovered that an alarmingly high 23 percent were at high risk for sleep apnea, and 76 percent of them had not previously been diagnosed.

From December 2005 until June the hospital screened 2,500 surgery patients, including Carr, with a questionnaire that ranked their risk for OSA. High-risk patients were sent home with a device worn on the head during sleep that would confirm a diagnosis.

The high-risk patients were flagged with purple wrist bracelets and on their chart to alert every caregiver in the system --from transporter to anesthesiologist -- to monitor them carefully and take steps to ensure their safety.

They included using fewer drugs that suppress the arousal response, positioning patients on their sides, and monitoring of them as they slept for periods of apnea or lowered blood-oxygen levels.

Avidan said the protocol complies with the ASA guidelines and may set a national benchmark for improving the safety of surgery patients with sleep apnea.

Obesity is a major risk factor of OSA, as soft tissue crowding in the throat leads to an airway collapse. Males over 40 are at higher risk. Increased neck thickness, snoring, daytime drowsiness and high blood pressure are often associated with OSA.

Finkel was the first author of an article about the hospital's initiatives to improve safety for patients with sleep apnea that was published in the July-August issue of Sleep Review. Finkel will present the preliminary results of the study on behalf of the research team at the ASA's annual meeting next month in Chicago.

Caplan of ASA couldn't say what percentage of hospitals screen surgery patients for sleep apnea, but said awareness of the problem is increasing.

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On the Net:

Sleep Review, July/August issue: http://www.sleepreviewmag.com/article.php?sSRM/2006/07

American Society of Anesthesiologists: http://www.asahq.org/