Comparison of Collapsibility of the Human Upper Airway During Anesthesia and During Sleep.

Background: The propensities for the upper airway to collapse during anesthesia and sleep are related, although much of our understanding of this relationship has been inferred from clinical observation and indirect measures such as the apnea-hypopnea index. The aim of this study was to use an identical, rigorous, direct measure of upper airway collapsibility (critical closing pressure of the upper airway) under both conditions to allow the magnitude of upper airway collapsibility in each state to be precisely compared.

Methods: Ten subjects (8 men and 2 women; mean ± SD: age, 40.