Anesthesia, sleep, and upper airway collapsibility.

Anesthesia and sleep both predispose to upper airway obstruction through state-induced reductions in pharyngeal dilator muscle activation and lung volume. The tendencies are related in patients with obstructive sleep apnea commonly presenting with difficulties in airway management in the perioperative period. This is a period of great potential vulnerability for such patients because of compromise of the arousal responses that protect against asphyxiation during natural sleep. Careful preoperative evaluation and insightful perioperative observation are likely to identify patients at risk. A significant proportion of patients will have previously undiagnosed obstructive sleep apnea and anesthesiologists are well placed to identify this potential. Patients with known or suspected obstructive sleep apnea need careful postoperative management, particularly while consciousness and arousal responses are impaired. Specific follow-up of suspected cases is needed to ensure that the sleep-related component of the problem receives appropriate care.