Vulnerability to Postoperative Complications in Obstructive Sleep Apnea: Importance of Phenotypes.

Obstructive sleep apnea (OSA) is a common comorbidity in patients undergoing surgical procedures. Patients with OSA are at heightened risk of postoperative complications. Current treatments for OSA focus on alleviating upper airway collapse due to impaired upper airway anatomy. Although impaired upper airway anatomy is the primary cause of OSA, the pathogenesis of OSA is highly variable from person to person. In many patients, nonanatomical traits play a critical role in the development of OSA. There are 4 key traits or "phenotypes" that contribute to OSA pathogenesis. In addition to (1) impaired upper airway anatomy, nonanatomical contributors include: (2) impaired upper airway dilator muscle responsiveness; (3) low respiratory arousal threshold (waking up too easily to minor airway narrowing); and (4) unstable control of breathing (high loop gain). Each of these phenotypes respond differently to postoperative factors, such as opioid medications. An understanding of these phenotypes and their highly varied interactions with postoperative risk factors is key to providing safer personalized care for postoperative patients with OSA. Accordingly, this review describes the 4 OSA phenotypes, highlights how the impact on OSA severity from postoperative risk factors, such as opioids and other sedatives, is influenced by OSA phenotypes, and outlines how this knowledge can be applied to provide individualized care to minimize postoperative risk in surgical patients with OSA.