Nasal CPAP: an objective evaluation of patient compliance

Am J Respir Crit Care Med. 1994 Jan;149(1):149-54. doi: 10.1164/ajrccm.149.1.8111574.


Nasal continuous positive airway pressure (NCPAP) improves sleepiness and prognosis in obstructive sleep apnea (OSA). Our objective was to document NCPAP compliance and the percentage of time that the effective pressure shown to eliminate 95% of the obstructive apneas and hypopneas was maintained. We built and covertly installed an elapsed timer and 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 complained of daytime sleepiness. Initial full night polysomnography demonstrated a mean apnea-hypopnea index (AHI) of 58 +/- 2.6 SEM (range, 10 to 115). Nine subjects discontinued therapy within 3 months for various reasons. In the remaining subjects (n = 38) the actual mean nightly hours 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 represents 91% of the time that prescribed effective pressure was maintained at the mask. The AHI did not correlate with compliance, but did correlate with effective use (R = 0.27048, p = 0.0006). Subjective initial complaints of daytime sleepiness correlated with compliance only during the first visit (R = 0.38590, p = 0.05). No predictors for compliance were found.

MeSH terms

  • Adult
  • Aged
  • Evaluation Studies as Topic
  • Female
  • Home Care Services
  • Humans
  • Male
  • Masks / statistics & numerical data*
  • Middle Aged
  • Nose*
  • Patient Compliance*
  • Polysomnography
  • Positive-Pressure Respiration / instrumentation
  • Positive-Pressure Respiration / psychology*
  • Positive-Pressure Respiration / statistics & numerical data*
  • Prognosis
  • Severity of Illness Index
  • Sleep Apnea Syndromes / diagnosis
  • Sleep Apnea Syndromes / psychology*
  • Sleep Apnea Syndromes / therapy*
  • Sleep Stages
  • Time Factors
  • Treatment Failure