The Perioperative Management of Patients With Obstructive Sleep Apnea

1

Introduction

The incidence of obstructive sleep apnea (OSA) has increased dramatically in the past two decades due to the increased incidence of obesity. Many continue to quote a 4% incidence of OSA in the adult population based on a 1994 report. A more recent study using data from the Wisconsin Sleep Cohort Study demonstrated an increased prevalence of OSA based on age, sex, and body mass index (BMI). Using data from the National Health and Nutrition Examination Survey, current estimates of moderate to severe OSA (Apnea/Hypopnea Index [AHI] measured as events/hour ≥15) are 3% among women and 10% among men aged 30 to 49 years and 9% among women and 17% among men aged 50 to 70 years. More importantly, 90% of patients with OSA are estimated to remain undiagnosed. Patients who undergo uvulopalatopharyngoplasty (UPPP) with or without tonsillectomy are most likely to have had a sleep study and a known diagnosis of OSA. However, they may or may not have had a full medical workup for comorbidities and may have complications perioperatively related to their OSA and not the surgical procedure.

The long-term effects of sleep-disordered breathing are associated with increased incidence of hypertension, cardiovascular events, diabetes, and premature death. All of these comorbidities need to be considered when evaluating the perioperative management of patients having surgery for OSA. Although many have written about the safety of performing UPPP with or without tonsillectomy as an outpatient, a more reasonable approach is to evaluate patients based on their current health status, not just the surgical procedure being performed. Pediatric and adult patients with OSA, even if asymptomatic, present special challenges that must be noted to decrease the risk of perioperative morbidity and mortality.

The Joint Commission has received 61 sentinel event reports in which the patient was diagnosed with or suspected of having OSA. Patients can experience complications when receiving opioids or concurrent sedatives (e.g. benzodiazepines) because the medications “diminish the protective arousal reflex triggered by hypoxia, increasing the risk of prolonged apnea and respiratory arrest.”

The Joint Commission announced OSA as a National Patient Safety Goal, focusing on preventing postoperative complications and harm. With the knowledge that 25% of the population has OSA and 90% are untreated, The Joint Commission required hospitals to:

• Screen patients who show signs they may have sleep apnea.

• Consider OSA when developing the anesthesia plan of care.

• Develop a protocol to deal with OSA that must be evidence-based best practice.

• Use the protocol for patients who are diagnosed with OSA and for patients who are not diagnosed but show signs that they may have OSA as well. The screening process should help staff identify the latter patients.

In 2014 the American Society of Anesthesiologists (ASA) Task Force updated practice guidelines for patients with OSA, which affect perioperative management, including recommendations for inpatient, observation, and outpatient procedures. The guidelines were developed to reduce the likelihood of adverse perioperative outcomes in patients with OSA. Task force members included anesthesiologists in private and academic practices, an otolaryngologist, a bariatric surgeon, and methodologists with expertise on development of practice parameters. The strength of evidence was described as supportive, suggestive, or equivocal when sufficient numbers of studies existed. With a lack of scientific evidence in the literature, the terms used were silent, insufficient, or inadequate.

2

Evaluation of the Patient with OSA

The preoperative evaluation of patients by anesthesia should include medical review of the patient and presence of increased BMI, hypertension, larger neck circumference, and a history of snoring or respiratory pauses. In the absence of a sleep study, a presumptive diagnosis of OSA may be made and perioperative management based on that assessment ( Table 62.1 ). The severity of OSA, the type of surgical procedure, and the need for postoperative analgesics should be considered in determining the perioperative risk from OSA ( Table 62.2 ).

Intraoperative concerns for patients with OSA focus on the choice of anesthetic, airway management, and patient monitoring. The task force agreed that OSA patients should be extubated when fully awake and strongly agreed that full reversal of neuromuscular blockade should be verified before extubation. Similarly, general anesthesia with intubation is preferable to moderate or deep sedation for procedures involving the upper airway such as bronchoscopy, septoplasty, or other procedures.

OSA patients have the propensity for airway collapse and rapid eye movement (REM) rebound, which occurs after sleep deprivation and carries an increased perioperative risk due to respiratory depressant and airway effects due to sedatives, opioids, and inhaled anesthetics.

Postoperative management concerns center on analgesia, oxygenation, positioning, and monitoring. Risk factors for respiratory depression are systemic administration of opioids, administration of sedatives, and the underlying severity of OSA. It is important to note that whether the case is inpatient, a 23-hour observation, or outpatient for UPPP with or without tonsillectomy, few patients spend 3 to 4 days in the inpatient setting. Exacerbation of respiratory depression may occur on the third or fourth postoperative day as normal sleep patterns develop and “REM rebound” occurs. Many patients with OSA demonstrate maximum oxygen desaturation during REM sleep. Patients with OSA have sleep deprivation and after surgery will show improvement in OSA and subsequent increase in REM sleep. With the use of opioids and/or sedatives in the postoperative period, the effect could be additive and problematic with maximum respiratory depression. Although pain control is important in the postoperative period to allow for adequate oral intake and to avoid emergency room visits and the possibility of hospital readmission for dehydration, this must be balanced with the concern regarding respiratory depression, hypoxemia, and even death.