NASAL CPAP - AN OBJECTIVE EVALUATION OF PATIENT COMPLIANCE

Nasal continuous positive airway pressure (NCPAP) improves sleepiness and prognosis in obstructive sleep apnea (OSA). Our objective was to d ocument NCPAP compliance and the percentage of time that the effective pressure shown to eliminate 95% of the obstructive apneas and hypopne as was maintained. We built and covertly installed an elapsed timer an d mask pressure transducer recorder in NCPAP units of 47 OSA patients. Subjects were seen at 2- to 8-wk intervals over 6 months. Group mean age was 51 yr; 38 males, with mean body mass index of 42; all complain ed of daytime sleepiness. Initial full night polysomnography demonstra ted a mean apnea-hypopnea index (AHI) of 58 +/- 2.6 SEM (range, 10 to 115). Nine subjects discontinued therapy within 3 months for various r easons. In the remaining subjects (n = 38) the actual mean nightly hou rs of use was 4.7 which represents 68% of the stated total sleep time (compliance). However, effective mean hours of use was 4.3 which repre sents 91% of the time that prescribed effective pressure was maintaine d at the mask. The AHI did not correlate with compliance, but did corr elate with effective use (R = 0.27048, p = 0.0006). Subjective initial complaints of daytime sleepiness correlated with compliance only duri ng the first visit (R = 0.38590, p = 0.05). No predictors for complian ce were found.