Perioperative management of obstructive sleep apnea: Ready for prime time?

PERIOPERATIVE MANAGEMENT OF OSA

When in doubt, proceed as if patient has OSA

Evidence of OSA’s association with postoperative complications is emerging, as noted above, but more specific information about risks is needed to develop effective management procedures. For surgical patients who are deemed to be at high risk for OSA, and for whom surgery cannot be delayed for diagnostic tests and OSA treatment, the most prudent course is to proceed with surgery but assume the patient has moderate to severe OSA. Anesthesiologists should be informed when patients are likely to have OSA, as they may choose a different strategy for managing anesthesia during surgery for patients at high risk. 

Management recommendations

The ASA published practice guidelines in 2006 for the perioperative management of patients with OSA.¹⁹ In view of the paucity of data on the best management strate­gies, the guidelines were based mostly on expert opinion. Their key recommendations include the following:

• Surgical patients should be screened clinically to determine their OSA risk. Any of the aforementioned screening tools is effective for this purpose. 
• For patients with a diagnosis of OSA or who are clinically determined to be at high risk, close attention to airway management is required, extubation should be done when the patient is fully awake (to reduce residual effects of anesthesia and sedatives), and regional anesthesia should be used whenever possible.
• Postoperative pain management in patients with confirmed or suspected OSA should minimize the use of opioids and other sedatives. Such patients also should undergo close pulse oximetry monitoring in a step-down setting after surgery and receive postoperative CPAP therapy as soon as possible.

These ASA recommendations are broadly echoed by a 2003 clinical practice review report of the American Academy of Sleep Medicine, which recommends careful attention during the first 24 hours after surgery in patients with presumed OSA and also cautions that patient-controlled analgesia may not be appropriate.²¹

Future research questions

Even with the insights reviewed above, many questions about perioperative management of OSA remain, including the following:

• Will the early diagnosis and treatment of OSA—usually with CPAP—improve perioperative and postoperative outcomes?
• What are the costs associated with observed complications of OSA, and will immediate and continued use of CPAP postoperatively prove cost-effective?
• Where should patients with OSA be monitored postoperatively, and for how long?
• Which pain-control strategies are best for patients with OSA?

DISCUSSION

Question from the audience: Have studies of OSA-associated postoperative complications stratified results on the basis of AHI score? 

Dr. Shafazand: Yes. In most studies, postoperative complications are more likely to occur among patients with AHI scores that indicate moderate to severe OSA. However, although the AHI is used extensively as a measure of OSA severity, it may not be the best measure. The degree and duration of oxygen desaturation are probably more relevant to the physiologic changes that occur than is the actual apnea or hypopnea event. The more severe the hypoxemia, the greater the risk of complications.

Comment from the audience: I want to reiterate the point from earlier in this summit that consultant physicians should avoid recommending a type of anesthetic in a preoperative consult. Despite the recommendations of the 2006 ASA guidelines,¹⁹ many anesthesiologists prefer to use a minimal opioid technique or a general anesthetic for patients with OSA rather than risk losing the airway during the operation and having to perform an emergent intubation.

Dr. Shafazand: I agree. In my own consultations I never presume to make recommendations about the type of anesthesia to be used. The important thing is to have a discussion with the anesthesiologist about the best way to manage patients with OSA, but not in the intraoperative context because the patient is going to be intubated and the airway will be protected. The discussion is really more about how to manage patients once they are extubated.

Question from the audience: Should patients with OSA undergo surgery in outpatient facilities?

Dr. Shafazand: It depends on the type and duration of the procedure. If it is a quick procedure, which is likely for an outpatient facility, with minimal sedation and a period of respiratory observation to ensure that the patient is fully awake, the outpatient setting is probably acceptable, especially if the patient is using CPAP at home. It also depends on the severity of OSA. For patients with more severe OSA, an outpatient facility is not recommended. Unfortunately, data about OSA complications in outpatient facilities are sparse.

Question from the audience: What is the role of overnight pulse oximetry versus a sleep study?

Dr. Shafazand: That is the Achilles’ heel of managing patients with OSA. Sleep labs are overbooked, so it is often not possible to order a sleep study for patients prior to surgery. Some studies have evaluated overnight pulse oximetry, noting the percentage of desaturation or the total time spent at less than 90% saturation during the night or per hour. This approach is probably adequate for screening for suspected severe OSA, but not all patients with OSA will have desaturations. Overnight pulse oximetry is at best a “poor man’s” screening tool—if it is negative, OSA cannot be ruled out.

Question from the audience: What is your opinion of surgical treatments for sleep apnea such as uvulopalatopharyngoplasty (UPPP)?

Dr. Shafazand: For patients with an AHI score below 15 and no comorbidities, some surgical correction may be advisable. For patients with an AHI score above 15, surgery can be recommended in some circumstances—for example, if there is a clear blockage of the nasal passage. But patients with moderate to severe OSA usually continue to require CPAP therapy after surgery. CPAP is still the recommended treatment for moderate to severe OSA, though surgery might help the patient tolerate CPAP better in certain instances by lowering the pressure requirements.

Question from the audience: A minimal number of hospitals actually screen patients for OSA and treat them differently. Do you know why the Joint Commission dropped a proposed safety goal to screen patients for OSA upon admission and treat based on the results?

Dr. Shafazand: I think the biggest problem is that results from the literature are so variable in terms of risks that it’s difficult to draw conclusions. Patients with desaturation are given oxygen to address the immediate problem, but there is no focus on complications. Depending on the study, there are true complications that affect patient safety but also add to the costs of care. Until there are more definitive results in the literature, there is not enough evidence to make and enforce recommendations.