The aim of this study was to investigate the response of auto-CPAP devices to respiratory events (apnea, hypopnea, flow-limitation and snoring) on the same condition using a physiological upper airway model. The hypothesis of this study is that collapsibility of the flow-limiting collapsible segment of the airway is influenced by the upstream airway resistance. Five auto-CPAP devices, AutoSet T, AutoSet Spirit, Goodnight 420E, PV10i and REMstar Auto were evaluated. Apnea: all the devices increased the auto-CPAP level, while AutoSet T and AutoSet Spirit did not respond to apnea for 30s. Hypopnea: all the devices except the AutoSet T and Goodnight 420E increased pressure. Flow-limitation: all the devices except the PV10i and REMstar Auto increased pressure. Snoring: the snoring sounds disappeared when REMstar Auto and PV10i were used, and the Goodnight 420E lowered the level of snoring. In conclusion, the response of auto-CPAP devices to respiratory events differed. Collapsible upper airway model with upstream resistance is useful for the first-step assessment of auto-CPAP devices.
