Background: Determination of the therapeutic pressure during continuous positive airway pressure (CPAP) therapy is usually performed by a technician during polysomnography. In recent years, several devices for automated adjustment of the therapeutic pressure by the means of computerized algorithms were developed. The aims of the present study were to compare two different devices for automated titration and to verify if unattended automated titration is a feasible strategy to determine the therapeutic CPAP.
Methods: We enrolled 16 consecutive patients with obstructive sleep apnea syndrome (OSAS) defined by an apnea-hypopnea index > 20/h. Automated titration was performed in the hospital using two CPAP devices (Autoset; Resmed; North Ryde, Australia; and Somnosmart; Weinmann; Hamburg, Germany) in random order for 2 consecutive nights, based on different signals for the detection of respiratory events. During titration, there was no direct supervision by a technician, and polysomnography was not recorded. We defined the therapeutic pressure as the 95th percentile of the airway pressure over time (P95).
Results: We observed significant differences of the P95 between the two devices, with an average of 7.0 ± 2.5 cm H2O for the Somnosmart and 9.9 ± 2.6 cm H2O for the Autoset (p = 0.005) [mean ± SD]. There was a considerable lack of agreement between the two devices, with a bias of 3.0 cm H2O and limits of agreement ranging from + 9.3 to − 3.2 cm H2O. We found no significant correlation between the paired differences of P95 and either indexes of severity of OSAS or lung function variables.
Conclusion: Automated titration based on the analyses of flow (Autoset) or forced oscillations (Somnosmart) predicted significant different therapeutic pressures for fixed CPAP therapy. Thus, unattended automated titration performed during 1 night of hospital stay with commercially available devices cannot be used to determine accurately the therapeutic CPAP in patients with OSAS.