Tens of thousands of people die each year from obstructive sleep apnea (OSA), including surgery patients who were not diagnosed with the condition or who have not managed the condition.

  • OSA can lead to hypertension, heart failure, arrhythmias, stroke, and sudden cardiac death.
  • Patients who are obese and older are at a greater risk for OSA.
  • The STOP-BANG screening tool can help identify those at risk for OSA.

More than 38,000 people die each year because of cardiovascular complications related to obstructive sleep apnea (OSA). This includes surgical patients who were not diagnosed with OSA prior to surgery. Thousands more die from car accidents and additional health-related problems associated with OSA. (Learn more at: http://bit.ly/2K57sZj.)

An estimated 27% of women and 43% of men 50 to 70 years of age have OSA. Nine in 10 of those with OSA are undiagnosed, research suggests.1 OSA is a sleep disorder that has cyclical alterations between pharyngeal collapse and arousals during sleep, causing episodes of hypoxemia and other problems.2

The condition is associated with hypertension, heart failure, arrhythmias, stroke, myocardial ischemia, and sudden cardiac death. When OSA patients undergo surgery, some sedatives, anesthesia, and postoperative analgesics can relax upper airway dilator muscles, potentially exacerbating OSA and leading to cardiovascular complications.2

Obesity and aging are factors often associated with obstructive sleep apnea, and these also are common demographics among ambulatory surgery center (ASC) patients.

“There is more awareness of OSA, and multiple studies have shown there is increasing obesity and an increased awareness of diseases associated with obesity, of which sleep apnea is one of them,” says Gaganpreet Grewal, MD, professor of anesthesiology at the University of Texas Southwestern Medical Center in Dallas.

Undiagnosed sleep apnea is common among surgery patients, says Dennis Auckley, MD, professor of medicine at Case Western Reserve University in Cleveland. One study of unrecognized OSA and postoperative cardiovascular complications revealed that 67% of surgery patients had mild, moderate, or severe sleep apnea.3 “Here, we do preoperative screening for all elective procedures,” Auckley says. “Ideally, this should happen long before they get to the operating room. [OSA] should be picked up by primary care doctors or surgeons in advance of surgery, but that often does not happen.”

Surgery centers can screen patients using the Sleep Apnea Screening Questionnaire, or STOP-BANG. (See box at the end of this article and read more at: http://bit.ly/2Wq8Koo.)

Unless surgeons and surgery centers have created a structured preoperative screening policy, surgery patients with undiagnosed OSA could receive anesthesia and opioids without doctors knowing of the risk. OSA is common enough during any surgery, including procedures in an ambulatory setting, that surgery center physicians and staff should have a high level of suspicion when treating any patient without a sleep apnea diagnosis, Grewal suggests.

“It’s not just one specialty’s responsibility,” Grewal says. “Everyone in the whole line of care needs to know, including the anesthesiologist, the surgeon, the post-op nurse, the discharge nurse who gives instructions, and the adults who will be watching patients for the next day or two after they go home.”

The danger of surgery center staff being unaware of OSA risks and failing to screen patients is that surgery carries grave risks for sleep apnea patients. The risk of surgery for patients with OSA is illustrated by the case of John LaChance, who died in 2007 following shoulder surgery. He was monitored overnight while receiving morphine for pain. The surgery center knew of his sleep apnea, but did not provide a continuous positive airway pressure (CPAP) machine. LaChance continued on pain medication even after he began vomiting. LaChance’s condition grew worse, and he suffered a brain hemorrhage due to anoxia, according to LaChance’s wife, Pat, who has become a blogger and spokeswoman for patient safety, including serving as a member of the Physician-Patient Alliance for Health & Safety. (Learn more about this story at: http://bit.ly/2Qs67wP.)

When patients receive an OSA diagnosis, some surgery centers will provide a CPAP machine during their post-op care. But if a patient screens as at risk and has not received a formal diagnosis made through the gold standard of a sleep study, it is trickier. “It’s controversial,” Grewal says. “CPAP machines are expensive, and insurance companies won’t cover them until there’s a sleep study. It could delay surgical care for the patient.”

For this reason, many surgery centers do not keep a CPAP on hand nor do staff recommend using a CPAP for patients who are at risk of OSA, but are not diagnosed. “The surgery centers still take the precautions of minimizing narcotics and utilizing other methods of pain control before giving sedating medication,” Grewal says. OSA patients’ biggest risk period is immediately after surgery. Interventions for at-risk patients are needed at that time, she adds.

“Obstructive sleep apnea is a significant public health concern because it can affect cardiovascular respiratory conditions, and the prevalence might be higher in surgical populations,” says Rebecca S. Twersky, MD, MPH, chief of anesthesia at the Josie Robertson Surgery Center at Memorial Sloan Kettering Cancer Center in New York City.

OSA is a condition that can be exacerbated on general anesthesia and opioids, placing patients at risk after surgery, Twersky explains. This is of concern to anesthesiologists, who worry patients will stop breathing in the recovery room or when they return home, she says.

Twersky and colleagues recently studied outcomes and safety among OSA patients undergoing cancer surgery procedures in an ASC. They found that patients at high risk for OSA or who had been diagnosed with OSA experienced more postoperative respiratory events than patients with moderate risk.4

Additional research shows that surgeons, anesthesiologists, and surgery centers can reduce the risk of OSA-related deaths by screening patients for OSA and taking precautions. For instance, one paper showed that identifying high-risk ambulatory patients can help centers develop a way to triage patients and better manage their care postoperatively.5 “Preoperative optimization of OSA patients centers around identification and managing comorbidities,” says Michael Walsh, MD, anesthesiologist at the Mayo Clinic. “OSA is associated with hypertension, arrhythmia, ischemic heart disease, pulmonary hypertension, and congestive heart failure. Preoperative identification of OSA patients can also tailor the anesthetic approach and postoperative care.”

Professional guidelines and current literature do not support postponing surgery to initiate CPAP treatment of apnea patients. But they do stress the importance of using CPAP for patients who are using the treatment already, Walsh notes.

“The main goal is to minimize opioid use and control pain with alternative methods, including nonsteroidal, acetaminophen, local, or regional anesthesia/analgesia,” he says.

By the time surgery patients head home, anesthesia should have worn off. But if doctors prescribe opioids for pain, this could be a problem for some OSA patients, Grewal says. “Currently, there’s just a background encouragement of avoiding opioids across the board, and that policy just happens to be useful for sleep apnea patients,” she says. Opioids are the main medication concern for OSA patients, but not the only one. Patients might be on anti-anxiety drugs, like Xanax, which also could increase risk from sleep apnea, Grewal adds.

“Also, there have been some studies saying that sleep architecture changes after having anesthesia could place patients at higher risk,” she says. “Sleep architecture is the pattern of different stages of sleep, like REM sleep.”

Grewal’s research suggests that obese patients should be screened before surgery for OSA, cardiovascular disease, respiratory disease, and endocrine disorders. As many as seven out of 10 severely obese patients have OSA.6 The functional capacity of severely obese patients might be difficult to assess, so they might need an ECG if they also have a history of heart disease, congestive heart failure, cerebrovascular disease, and other risk factors.6

It is difficult for researchers to measure apnea events after patients return home, but research shows that OSA patients can undergo a variety of ambulatory procedures and head home without any higher complication rates vs. those OSA patients who are admitted to the hospital as a precaution.6 The key is that surgery centers and physicians take precautions immediately after the surgery to ensure patients at risk of OSA complications are handled safely, Grewal adds.

“I use non-opioid pain control methods and careful monitoring before discharge,” Grewal says. “We also provide thorough education to patients and patients’ caregivers.”

ASCs might keep in mind that issues related to OSA will increase as they take on more complex cases. If centers do not already follow evidence-based guidelines, now might be the time to start.

“There is a safety concern as outpatient surgeries become more complex and patient comorbidities increase,” Walsh says. “Ambulatory anesthesia safety focuses on getting the correct patient into the right location for the appropriate surgery. These decisions need to be data-driven.”

The Society for Ambulatory Anesthesia and the American Society of Anesthesiologists have made collecting ambulatory outcome data a priority, Walsh says. “With better data, we may be able to identify the highest-risk OSA patients and highest-risk surgeries, and make data-driven triaging decisions.”


  1. Chung F, et al. Society of Anesthesia and Sleep Medicine guidelines on preoperative screening and assessment of adult patients with obstructive sleep apnea. Anesth Analg 2016;123:452-473.
  2. Chan MTV, et al. Association of unrecognized obstructive sleep apnea with postoperative cardiovascular events in patients undergoing major noncardiac surgery. JAMA 2019;321:1786-1798.
  3. Auckley D, Memtsoudis S. Unrecognized obstructive sleep apnea and postoperative cardiovascular complications: A wake-up call. JAMA 2019;321:1774-1776.
  4. Szeto B, et al. Outcomes and safety among patients with obstructive sleep apnea undergoing cancer surgery procedures in a freestanding ambulatory surgical facility. Anesth Analg 2019; Apr 8. doi: 10.1213/ANE.0000000000004111. [Epub ahead of print].
  5. Walsh MT. Improving outcomes in ambulatory anesthesia by identifying high risk patients. Curr Opin Anaesthesiol 2018;31:659-666.
  6. Grewal G, Joshi GP. Obesity and obstructive sleep apnea in the ambulatory patient. Anesthesiol Clin 2019;37:215-224.


The Sleep Apnea Screening Questionnaire, or STOP-BANG, scores one point for each “yes” answer to these questions. Any scores of 3 or higher suggest obstructive sleep apnea risk:

  • S = Do you snore loudly?
  • T = Do you often feel tired, fatigued, or sleepy during the day?
  • O = Do you have observed apnea?
  • P = Do you have or are you receiving treatment for high blood pressure?
  • B = Are you obese/very overweight (BMI more than 35 kg/m2)?
  • A = Are you 50 years of age or older?
  • N = Is your neck circumference greater than 16 inches?
  • G = Is your gender male?2,4