BIG PROBLEM Obese patients may present for surgery with obstructive sleep apnea, making intubation more difficult.

Can you perform surgery on obstructive sleep apnea patients in the outpatient setting? Yes, absolutely. But should you? That answer is a little more complicated. You can consider patients with known or presumed diagnoses of OSA and optimized comorbid medical conditions for ambulatory surgery, so long as you follow these guidelines from the Society for Ambulatory Anesthesia OSA task force during each phase of surgery.

1. Pre-op screening
Screen all patients for OSA using the STOP-BANG questionnaire (see page 44) and physical examination, as OSA is actually a relatively common sleep-related breathing disorder that often goes undiagnosed. Because OSA is associated with significant consequences such as daytime sleepiness, neurocognitive dysfunction, cardiovascular disorders (such as hypertension, ischemic heart disease, arrhythmia, pulmonary hypertension and congestive heart failure), metabolic dysfunction and impaired quality of life, it poses a real surgical risk.^1—5

What's more, the prevalence of OSA is increasing and is reported to be higher in the surgical population than in the general population.^6,7 As such, it's likely outpatient facilities and their anesthesia providers will increasingly encounter patients with OSA — diagnosed or not — in the ambulatory setting. So, in addition to screening using STOP-BANG to determine suspected OSA, you should also assess the patient's comorbid conditions, including hypertension, arrhythmias, heart failure, cerebrovascular disease and metabolic syndrome.

If OSA is suspected during the pre-operative evaluation, you can proceed with a presumptive diagnosis of OSA, albeit with caution. If a patient is on pre-operative CPAP, assess and encourage adherence to CPAP. Make sure that the surgical team is aware of the patient's status. Educate the patient and his caregiver(s) regarding the potential concerns, the use of non-opioid analgesics and avoidance of opioids post-op, and that the patient should sleep propped up, if possible, after surgery. Reiterate these concerns and instructions after surgery as well.

PRE-OPERATIVE SCREENING

Root Out OSA With STOP-BANG

Ask these questions to determine whether patients may suffer from obstructive sleep apnea, whether they've been diagnosed or not.
S = Snoring. Do you snore loudly — louder than talking or loud enough to be heard through closed doors?
T = Tiredness. Do you often feel tired, fatigued or sleepy during the daytime?
O = Observed apnea. Has anyone observed your stopping breathing during your sleep?
P = Pressure. Are you being treated for high blood pressure?

 

B = BMI > 35
A = Age > 50 years
N = Neck circumference > 40cm
G = Male gender

• Moderate-to-severe OSA: 6 or more questions answered "yes"

— Girish P. Joshi, MBBS, MD, FFARCSI

2. Intraop actions
Use regional anesthetic techniques whenever possible in patients with OSA. If general anesthesia has to be used, choose a technique that allows early emergence.

Minimize perioperative opioid use, as these drugs have a depressive effect on the respiratory system, and patients with OSA are already coming to you compromised in this area. Instead, employ a multi-modal, non-opioid analgesic approach: regional analgesia techniques, wound infiltration with local anesthetics, acetaminophen, NSAIDs and dexamethasone (if no contraindications).

ESSENTIAL TOOLS

Airway Access Aids

When standard intubation attempts fail, the next best option in most cases is mask ventilation, says anesthesiologist Ashish Sinha, MD, PhD, DABA, vice chairman of clinical research at Drexel University College of Medicine in Philadelphia, Pa.

If that doesn't work, he says, grab a laryngeal mask airway. "Placing an LMA in the airway, getting the patient to take a few breaths to move oxygen in and out, lets you relax, take your time and approach the airway again," he explains.

But if an LMA can't be used because of the type of case — thyroid surgery, for example — opt for blind or fiber-optic nasal intubation or video-assisted laryngoscopy. Video laryngoscopes are a safe, easy fallback when all else fails, says Dr. Sinha.

Why is the popularity of video laryngoscopy increasing among providers? Dr. Sinha explains that during standard intubation, you're trying to align the oral, laryngeal and phalangeal axes, and you can't see the vocal cords if you're unable to align them in a straight line. When working with a video laryngoscope that lets you see "around the corner" of the airway, you don't have to align the axes for a direct view of the glottis.

"Some providers call that cheating," says Dr. Sinha. "So what? Video laryngoscopes not only make intubation possible, they make it easier. Why make intubation harder than it needs to be?"

— Daniel Cook

If opioids will be used, choose shorter-acting options such as remifentanil, fentanyl and sufentanil intraoperatively. Titrate longer-acting opioids (such as morphine and hydromorphone) for a more controlled post-operative effect.

Use prophylactic antiemetics such as ondansetron (4mg) and dexamethasone (4mg, if no contraindication). Finally, perform tracheal extubation awake.

3. Post-op precautions
Once the patient is out of the OR and recovering PACU, maintain him in a 25° to 30° head-up position, so long as there are no contraindications to doing so. Employ CPAP in patients who were using it pre-operatively or in patients for whom SaO₂ is 85% on 2 to 3L/min. Observe closely for apneic episodes.

For pain control, again use non-opioids whenever possible and titrate any opioids to make the patient comfortable, not to achieve a particular pain score. Balance the degree of pain with concerns about sedation and respiratory depression. Regional blocks can be placed post-op to provide safer, long-lasting pain relief.

Monitor the patient in PACU until he is completely awake and maintains SaO₂ at baseline. Exercise caution in OSA patients who develop prolonged and frequent severe respiratory events (such as sedation/ analgesic mismatch, desaturation, and hyponeic or apneic episodes) in the post-operative period. Most adverse events occur within 2 hours after surgery, so keeping close watch is of particular import.

Ask patients placed on an OSA protocol based on clinical indicators to follow up with their primary physicians for a possible sleep study. Instruct patients on pre-operative CPAP that they should use CPAP when sleeping, daytime or nighttime. Finally, tell OSA patients to avoid opioids if possible, and not to take sedatives and/or muscle relaxants.