Extended evaluation of the efficacy of a proactive forced oscillation technique-based auto-CPAP algorithm.

Abstract

Previous studies revealed substantially varying therapy efficacy of automatic continuous positive airway pressure (APAP) devices in the treatment of obstructive sleep apnea (OSA). We evaluated the efficacy of a new APAP device using the forced oscillation technique (FOT) to evaluate upper airway obstruction during apneas and flow contour analyses during hypopneas. Forty-six initially diagnosed OSA patients were included and the pressure range was set from 5 to 20hPa. Therapy efficacy was assessed based on the reduction of apnea-hypopnea index (AHI), improvement of objective sleep quality parameters, and the appropriateness of the device's pressure regulation. AHI and arousal index significantly decreased during APAP therapy (median [interquartile range]: AHI 36 [23-55] vs. 2 [1-6]/h, arousal index 30 [22-45] vs. 15 [10-19]/h, both p < 0.001). The amount of slow wave sleep (SWS) and rapid-eye-movement (REM) sleep significantly increased (SWS 20 [14-29] vs. 29 [19-34]%, REM 16 [11-21] vs. 24 [14-30]%, both p < 0.01). Most residual respiratory events during therapy were of central etiology and attributable to five patients, who presented with treatment-emergent central sleep apnea. The device's pressure regulation abolished most obstructive respiratory events (n = 6.7 residual obstructive events per patient). Of central respiratory events, 534/646 (83%) did not lead to pressure increases. This pilot study provides a proof of concept that the APAP device combining FOT and evaluation of flow contour allows for the suppression of obstructive events without relevant false reactions.