TREATMENT OF OBSTRUCTIVE SLEEP-APNEA WITH A SELF-TITRATING CONTINUOUSPOSITIVE AIRWAY PRESSURE (CPAP) SYSTEM

Conventional manually adjusted continuous positive airway pressure (CP AP) is an effective therapy for sleep-disordered breathing. We prospec tively investigated the efficacy of a self-titrating nasal CPAP system in the acute treatment of obstructive sleep apnea (OSA) syndrome. Twe nty patients with moderately severe OSA [apnea hypopnea index (AHI) >1 5/hour] were enrolled in a randomized, controlled, prospective clinica l trial. An initial diagnostic sleep study was performed, followed by randomization to a manually adjusted CPAP titration on one night and s elf titrating CPAP on the other night. On the conventional CPAP night, the CPAP was manually adjusted until abolition of all apneas and elec troencephalographic (EEG) arousals, whereas the self-titrating CPAP wa s set in automatic mode at lights out. The self-titrating CPAP system utilized an algorithm based on airway vibration patterns to detect air way stability. The AHI decreased from 50.8 +/- 28.8/hour [mean +/- sta ndard deviation (SD)] at baseline to 3.8 +/- 3.1/hour (p < 0.005) duri ng manually adjusted and 6.1 +/- 5.3/hour (p < 0.005) during self-titr ating CPAP. The arousal index (Ar-I) decreased from 34.1 +/- 23.1/hour (baseline) to 11.2 +/- 5.0/hour on manual adjustment (p < 0.005) and 11.3 +/- 0.3/hour on self titration (p < 0.005), whereas total sleep t ime was unchanged. No significant differences in any measure of oxygen ation or sleep architecture were observed between the manually adjuste d and self-titrating CPAP nights except that the lowest arterial oxyge n saturation (SaO(2)) was higher with manual titration (84.4 +/- 4.2% vs. 79.9 +/- 9.7%, p < 0.05). The maximum pressure required for abolit ion of apneas and arousals was significantly lower (p < 0.05) during t he self titrating study (10.1 +/- 3.8 cmH(2)O) as compared to manually adjusted CPAP (12.3 +/- 3.9 cmH(2)O). Failure to increase pressure an d failure to maintain minimum pressure occurred in 7 of the 20 subject s during the self-titrating study. This required manual resetting of t he system in five subjects, but the system self-corrected in two subje cts. An unsupervised study would have resulted in undertreatment of OS A. Based on a single-night laboratory study, self-titrating CPAP was w ell tolerated and improved OSA and sleep architecture comparable to ma nually adjusted CPAP. The future modifications of this prototype will require further research to assess its efficacy and safety in the labo ratory and home environments before its recommendation for general lon g-term use.