Auto-CPAP (APAP) for treatment of obstructive sleep apnea

Nasal continuous positive airway pressure (CPAP) is the treatment of choice for moderate to severe obstructive sleep apnea (OSA). This treatment works by providing a pneumatic splint that prevents upper airway collapse during sleep. AutoCPAP (APAP) can provide a solution to some traditional problems. The devices monitor some or all of the following variables: flow (apnea or hypopnea), snoring (airway vibration), airflow profile flattening (airflow limitation), or airway impedance (forced oscillation technique). Each APAP device has proprietary algorithms to slowly increase pressure in response to the detected respiratory events. Once all events are eliminated, pressure is slowly reduced until events are again detected. In this manner the lowest effective pressure is provided (auto-adjusting). In some patients the average nightly pressure may be up to 6 cm H/sub 2/O less than the maximum pressure required. AutoCPAP devices have been shown to be useful for auto-titration and chronic treatment. In the auto-titrating mode they can be used to select a fixed level of CPAP for conventional treatment in the majority of cases. The use of unattended titration protocols requires more study. Proper patient selection and education are probably needed for success. As a chronic treatment there is conflicting evidence for and against the premise that APAP will increase acceptance and adherence to positive pressure treatment. However, there may be segments of the OSA population that will find APAP treatment much more acceptable.