Many OSA patients use bilevel devices because they need a lower pressure during exhalation. The lower pressure makes treatment more comfortable.
Bilevel devices offer the most significant improvements in comfort when they achieve patient-machine synchrony. In other words, the bilevel device needs to stay in sync with you on each inhale and exhale. ResMed's patented VsyncTM and TiControlTM technology provide excellent synchrony, even with air leaks.