Should patients with obstructive sleep apnea be handled as outpatients?

Condition often is undiagnosed and may result in cardiopulmonary arrest

A hospital had seven respiratory arrests among its surgery patients in a short time period. A root-cause analysis surprised managers when it determined a common trait in all seven patients: obstructive sleep apnea (OSA).

A recent report in the Anesthesia Patient Safety Foundation Newsletter described eight cases of "unexplained" postoperative cardiopulmonary arrests.1 "All patients received parenteral narcotics and were ultimately diagnosed with OSA," according to Janet van Vlymen, MD, FRCPC, assistant professor in the department of anesthesiology, Queen’s University, Kingston General Hospital in Ontario, Canada. Van Vlymen participated in a discussion on sleep apnea published by the Park Ridge, IL- based Society of Ambulatory Anesthesia.

There are 19 cases of patients with OSA in the closed claims database of the Park Ridge, IL-based American Society of Anesthesiologists, according to van Vlymen. "In 18 of 19 cases, the patient sustained brain damage or death related to adverse respiratory system events," she wrote.

Some outpatient surgery providers report being "besieged" with patients having the diagnosis of obstructive sleep apnea, which is a sleep-related breathing disorder.2

"It’s the newest patient syndrome on the horizon," says Yvonne Mull, RN, CNOR, former director of nursing at HealthSouth Alaska Surgery Center in Anchorage. Mull has published on the topic of OSA.

And there’s even more frightening news. According to published reports, 80% to 95% of the approximately 18 million Americans believed to have OSA arrive for surgery without a diagnosis of OSA.3-4

David O. Warner, MD, professor of anesthesiology and vice chair for research at the anesthesia clinical research unit in the department of anesthesiology at the Mayo Clinic in Rochester, MN, says, "It is suspected that the numbers are increasing as average weight of the population increases, but it is equally likely that increased awareness of the syndrome, and improvements in diagnosis and treatment, account for the fact that it seems we are seeing more of these patients."

Don’t expect the number of patients with OSA to diminish soon.

"We do know that the number of patients with OSA is expected to increase five- to tenfold over the next decade," van Vlymen wrote.

What are the symptoms?

How can you recognize whether a patient has OSA? Sources and studies estimate that the percentage of patients with OSA who are obese ranges from 50% to 90%.5-6 Symptoms of the condition include abnormal breathing during sleep (apnea and/or snoring), frequent arousals (periodic extremity twitching, vocalization, turning, and/or snorting) and daytime somnolence.7

Anesthesia may increase the number and duration of sleep apnea episodes and may decrease arterial oxygen saturation, according to the Washington, DC-based American Sleep Apnea Association. "Further, anesthesia inhibits arousals that would occur during sleep," it stated.8

Sedative medication, such as anesthesia, suppresses upper airway muscle activity, the association warned.

Grover R. Mims, MD, medical director of the Outpatient Surgical Center at Wake Forest Univer-sity Baptist Medical Center in Winston Salem, NC, says, "The most important thing is being aware that these patients have problems, and [OSA] can cause problems in the immediate waking up of patients in the early post-op period."

The American Sleep Apnea Association says that given the nature of the disorder, it may be fitting to monitor sleep apnea patients for several hours after the last dose of anesthesia and opioids or other sedatives. The association suggested that possibly the monitoring should continue through one full natural sleep period. "Hence there is concern that same-day surgery . . . may not be appropriate for some sleep apnea surgery patients," the association stated.8

Most OSA patients are obese and need various therapies and equipment that aren’t normally available in a same-day surgery facility, says Jonathan L. Benumof, MD, professor of anesthesiology at the University of California, San Diego Medical Center.

These requirements include specialized airway management equipment such as fiberoptic bronchoscopes, respiratory therapy treatment and equipment such as continuous positive airway pressure (CPAPs) and mechanical ventilator devices, monitoring equipment such as continuous pulse oximetry in the recovery room and elsewhere, and immediate availability of chest X-rays, arterial blood gases, 12-lead EKGs, and arterial and central venous catheters, he maintains.

Additionally, the facility needs to have skilled personnel such as respiratory therapy technicians, X-ray technicians, and EKG technicians who are available to come to the bedside with their equipment, Benumof says. "Often, those are not present in an outpatient facility," he says. Staff also should be skilled in areas such as advanced cardiac life support, he says.

Another reason to consider these patients for inpatient surgery is that the patient’s increased sensitivity to narcotics and sedatives means that ventilation may be depressed, Benumof warns. "The arousal response is even more likely to be depressed, and because the arousal response is depressed, the severity of OSA will increase," he says.

Also, because most of these patients are obese, the chest walls are heavy, the lungs are small and carry less oxygen, and the tracheobronchial tree is small, Benumof says.

Airway resistance is decreased, and these obese patients have higher consumption of oxygen, he says. Additionally, consider the cardiovascular ravages of OSA, he says. "Many of these people have high blood pressure and cardiac enlargement."

When considering outpatient surgery on OSA patients, consider whether factors such as obesity, cardiovascular disease, as well as the OSA itself are mild or severe, he says. "You also have to decide whether the surgery is appropriate for an outpatient setting," he emphasizes.

If all of the factors are mild, and the procedure is appropriate, then an OSA patient can have outpatient surgery, Benumof states. However, if one single factor is severe, then patients should have inpatient surgery, he adds.

"It is absurd to think that we can manage a 5-foot, 8-inch, 440-pound, BMI equal 69, morbidly obese patient with a history consistent with severe OSA for an outpatient knee arthroscopy in the same manner as we do for a non-OSA, normal-weight patient," Benumof wrote in an article. "Nevertheless, this difficult problem is currently being presented to many anesthesiologists daily."7

A recent study by Warner and others shined a more positive light on outpatient surgery for OSA patients. This retrospective analysis indicated that the preoperative diagnosis of OSA was not a risk factor for unanticipated hospital admission or for other adverse events among patients undergoing outpatient surgical procedures in a tertiary referral center.9

However, van Vlymen says she found several problems with this study. "There was a very high unanticipated admission rate [24%], the controls were obese and not screened for symptoms of OSA, the OSA group was a mixture of treated and untreated, and there was no information about complications for patients who were sent home," she wrote.2

Warner says that most procedures that are less invasive enough to be performed as an outpatient in normal circumstances could be performed in many patients with OSA. "Typically, these would be procedures that do not require long-acting opioids for postoperative pain relief," he adds.

Ultimately, each institution needs to develop guidelines for managing these patients, van Vlymen said. "I think it is imperative that patients are screened preoperatively for symptoms of OSA and elective surgery postponed until they can be assessed and treated," she wrote. "Adequately treated OSA patients may be considered for ambulatory surgery if they are having minor surgery with minimal need for postoperative analgesics, are alert and are willing and able to use nCPAP [nasal continuous positive airway pressure] themselves at home for all sleep periods."2

Warner encourages more studies. "Most of the discussion and debate regarding these patients is occurring in the absence of good data and is driven by anecdotes of postoperative catastrophes," he says.

References

1. Lofsky A. Sleep apnea and narcotic postoperative pain medication: A morbidity and mortality risk. Anesthesia Patient Safety Foundation Newsletter 2002; 17:21-32.

2. SAMBA Talks August 2003. Web: www.sambahq.org/professional-info/enewsletter.html. Accessed July 3, 2003.

3. National Commission on Sleep Disorders Research. Wake up America: A National Sleep Alert. Washington DC: Government Printing Office; 1993.

4. Young T, Evans L, Finn L, et al. Estimation of the clinically diagnosed proportion of sleep apnea syndrome in middle-aged men and women. Sleep 1997; 20:705-706.

5. Benumof JL. Obstructive sleep apnea in the adult obese patient: Implications for airway management. J Clin Anesth 2001; 13:144-156.

6. Bresnitz EA, Goldberg R, Kosinski RM. Epidemiology of obstructive sleep apnea. Epidermiol Rev 1994; 16:210-227.

7. Benumof JL. Policies and procedures needed for sleep apnea patients. Anesthesia Patient Safety Foundation Newsletter Winter 2002-2003; 17:49-68.

8. American Sleep Apnea Association. Sleep Apnea and Same-Day Surgery. Web: www.sleepapnea.org/sameday. html. Accessed Sept. 23, 2003.

9. Sabers C, Plevak DJ, Schroeder DR, et al. The diagnosis of obstructive sleep apnea as a risk factor for unanticipated admissions in outpatient surgery. Anesth Analg 2003; 96: 1,328-1,335.

Source

For more information on obstructive sleep apnea, contact:

  • Grover R. Mims, MD, Medical Director, Outpatient Surgical Center, Wake Forest University Baptist Medical Center, Winston-Salem. E-mail: gmims@wfubmc.edu.
  • Yvonne Mull, 13320 Floral Lane, Anchorage, AK 99516.
  • David O. Warner, MD, 200 First St. S.W., Rochester, MN 55905. E-mail: warner.david@mayo.edu.