Abstract and Introduction
Abstract
Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder, and the difficult airway is perhaps the anesthesiologists’ quintessential concern. OSA and the difficult airway share certain similar anatomical, morphological, and physiological features. Individual studies and systematic reviews of retrospective, case-control, and large database studies have shown a likely association between patients with OSA and the difficult airway; OSA patients have a 3- to 4-fold higher risk of difficult intubation, difficult mask ventilation, or a combination of both. The presence of OSA should initiate proactive perioperative management in anticipation of a difficult airway. Prudent intraoperative management comprises the use of regional anesthesia where possible and considering an awake intubation technique where there is the presence of notable difficult airway predictors and risk of rapid desaturation following induction of general anesthesia. Familiarity with difficult airway algorithms, cautious extubation, and appropriate postoperative monitoring of patients with OSA are necessary to mitigate perioperative risks.
Introduction
Recognition, anticipation, and planning for a potential difficult airway are key issues in safe perioperative management. Studies from the United Kingdom[1] and United States[2] show that failed perioperative airway management remains a significant problem resulting in brain damage or death. Over the last decade, major airway societies[3–5] have published guidelines for assessment and management of the difficult airway; however, there is little information in these guidelines specifically pertaining to obstructive sleep apnea (OSA).
With the increasing prevalence of obesity, the prevalence of OSA is also rising; it ranges from 9% to 25% in the general adult population, with 25% of men and 10% of women estimated to have OSA.[6] Patients with OSA and difficult airway share certain anatomic, morphologic, and physiologic features:[7] (1) obesity and OSA increases the volume of soft tissue surrounding the pharyngeal airway, (2) greater visceral fat reduces lung volume and thus increases the propensity for pharyngeal wall collapse, and (3) neural compensation is depressed during sleep and anesthesia. These problems are compounded, where present, by narrow skeletal confines, such as with retrognathia.
A systematic review by Singh et al[8] showed that ultrasound airway parameters, including tongue base thickness and retroglossal diameter, are correlated to the severity of OSA. Thus, OSA patients have features of an anatomically difficult airway due to a crowded collapsible pharyngeal space, compounded by physiological problems related to lower functional residual capacity and increased oxygen consumption, both leading to faster oxygen desaturation.[9] Another recent meta-analysis demonstrated that patients with OSA, compared to patients without OSA, have a 3–4 times higher risk of difficult intubation, difficult mask ventilation, or both.[6] Conversely, 66% of patients with difficult intubation have been shown to be diagnosed later to have OSA.[10] The recent Society of Anesthesia and Sleep Medicine guideline on intraoperative management of patients with OSA provides a valuable overview of perioperative airway management.[11]
The purposes of this review are (1) to evaluate the evidence for the association between OSA and difficult airway, and (2) to discuss optimal airway management of an OSA patient undergoing either nonairway or upper airway surgery.