Sleep, anesthesia, and the upper airway

Upper airway obstruction is a common problem during both sleep and anesthesia, and these tendencies are related in individuals. Patency of the upper airway is determined by the balance of forces across the pharyngeal wall. Airway narrowing, increased extra luminal tissue pressure, and increased airway wall compliance predispose to collapse, particularly during inspiration as negative intraluminal pressures are generated. The tendency to collapse is resisted by airway muscle activation, which is driven by a combination of influences including state-related wakeful stimulation, negative pressure reflexes, and respiratory neuronal activity. This activation decreases with both sleep and anesthesia increasing the tendency to obstruction, and there are substantial overlaps in the way in which these states modulate this neuronal compensatory activity. The common ground between sleep and anesthesia in all these considerations emphasizes the importance of seeking and applying information regarding breathing during sleep to everyday anesthesiology practice.