Do you know if you are likely to have obstructive sleep apnea? A team of anesthesiologist researchers has developed a quick, cheap and highly accurate scoring system to identify surgical patients who may have the potentially life-threatening condition of obstructive sleep apnea (OSA).

The STOP questionnaire is a self-administered screening tool consisting of four simple yes/no questions that was created by anesthesiologist Francis Chung, M.D., and her team from the University of Toronto.

Obstructive sleep apnea is the most prevalent breathing disturbance in sleep and is characterized by repeated episodes of cessation of breathing due to a narrowing of the airway.

It is estimated that OSA affects anywhere from 2 to 26 percent of the general population. Even more alarming is that around 80 percent of men and 93 percent of women with moderate to severe sleep apnea are unaware they have this disorder. More alarming still is that the estimated average life span of an untreated sleep apnea patient is 20 years shorter than the average life span of the rest of the population.

Simple, validated methods of screening for obstructive sleep apnea have long been needed, especially for anesthesiologists, such as Dr. Chung, who are the physicians responsible for the overall care of patients before, during and after surgery.

“Identifying patients with OSA is the first step in preventing postoperative complications,” said Dr. Chung. “Untreated OSA patients are known to have a higher incidence of difficult intubation, postoperative complications, increased intensive care admissions and greater duration of hospital stay.”

Jeffrey B. Gross, M.D., Chairman of the ASA Task Force for Perioperative Management of Patients with Obstructive Sleep Apnea, agrees that, “Identifying patients who are at risk of having OSA in advance of surgery is important to improve patient safety. In addition, when anesthesiologists are forewarned of the severity of a patient’s sleep apnea, they can select appropriate anesthetic techniques and equipment, and ensure that surgery takes place in a facility which is equipped to deal with the potential complications.”

Obstructive sleep apnea is also known to be an independent risk factor for high blood pressure, heart attack, irregular heart rhythm, diabetes and is even associated with a high risk for traffic accidents.

Unfortunately, screening processes for surgical patients are not routine in most hospitals and clinics because no simple, practical tool has yet to be definitively validated to identify OSA in these patients.

“An overnight sleep study is the most reliable way to diagnose OSA, but it is too time-consuming and expensive for every patient to receive before surgery,” said Dr. Chung.

The STOP Questionnaire for OSA

The STOP test consists of four questions:
S: Do you snore loudly?
T: Do you often feel tired, fatigued or sleepy during daytime?
O: Has anyone observed you stop breathing during sleep?
P: Do you have or are you being treated for high blood pressure?

If a patient answers “yes” to two or more of these questions, then he or she is ranked as being at high risk for obstructive sleep apnea. When combined with other known risk factors for OSA - high body mass index, age over 50, large neck circumference and male gender ― the sensitivity for predicting OSA was even greater.

In a companion study to the STOP questionnaire study, Dr. Chung and colleagues also validated two other screening tools that have been used previously but not definitively validated for surgical patients: the 11-question Berlin Questionnaire and the American Society of Anesthesiologists (ASA) checklist, which contains 12 checkable items for adults and 14 for children.

The validation of these three studies offers anesthesiologists and other health care professionals objective, reliable tools for detecting OSA in their surgical patients. But for Dr. Chung and others, identifying high-risk patients is just the important first step in helping to keep these patients safe at all times.

“Now we are conducting more research investigations on the topic,” said Dr. Chung. “We hope that the evidence from our research will lead to the development of an overall care protocol for patients with OSA and the patients at high risk of having obstructive sleep apnea” (Newswise).