A SLEEP LABORATORY EVALUATION OF AN AUTOMATIC POSITIVE AIRWAY PRESSURE SYSTEM FOR TREATMENT OF OBSTRUCTIVE SLEEP-APNEA

Study Objectives: This paper compares the performance of an experiment al nasal positive airway pressure device that automatically adjusts th e level of applied pressure (APAP) with the performance of a conventio nal continuous positive airway pressure (CPAP) in a sleep laboratory s tudy. Design: In a randomized sequence, conventional CPAP therapy was applied for I night (CPAP night) and APAP therapy the following night (APAP night). Setting: The study was conducted in an accredited sleep disorders center. Patients or Participants: Twenty-six men and 5 women between the ages of 35 to 73 (51+/-9.6) years with body mass index 35 .82+/-8.35 (kg/m(2)) who were diagnosed (using standard nocturnal poly somnography [NPSG] methods) as having OSA syndrome were studied. The s ubjects were treated with conventional CPAP for approximately 8 (7.79/-3.16) weeks at home prior to their participation in this study. Meas urements and Results: All standard polysomnography data and nasal mask pressures were recorded using a computer-based data acquisition syste m. Sleep and respiratory data were scored by a registered polysomnogra pher. The mean apnea-hypopnea index (AHI) for subjects for the NPSG ni ght was 55.2+/-33.7. It dropped to 4.2+/-3.8 for the CPAP night and to 5.4+/-5.4 for the APAP night. There was no significant (p=0.05) diffe rence between mean AHI indices, sleep stages, sleep stage shifts, and snore arousals for CPAP night and APAP night. However, all the measure s showed significant (p=0.05) improvement over NPSG night. The mean of APAP applied pressure (8.4+/-3.3 cm H2O) was significantly (p=0.05) l ower than the prescribed pressure (11.5+/-3.1 cm H2O), but there was n o significant (p=0.05) difference between the maximum APAP applied pre ssure (12.8+/-4.3 cm H2O) and the prescribed pressure (11.5+/-3.1 cm H 2O). All mean comparison tests were carried out using two-tailed stati stics. Conclusions: APAP appears to be as effective as CPAP in treatin g OSA patients. APAP delivers the same level of therapy as CPAP, but i t reduces the average airway pressure while providing needed peak pres sures.