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In a retrospective cohort study, we evaluated whether improvements in nasal continuous positive airway pressure (nCPAP) technology, particularly the introduction of automatic adjustment of the nCPAP pressure (auto-CPAP), have led to better acceptance and (long-term) compliance in patients with obstructive sleep apnea syndrome (OSAS) as compared to earlier reported data. Questionnaires were sent to 256 patients, who were referred to our clinic for an overnight polysomnography from January 1997 to July 2005 and received nCPAP therapy for OSAS. Of the 256 patients, 24 patients were unavailable for follow-up. Of the remaining 232 patients, 58 patients (25%) had discontinued therapy, while 174 patients (75%) were still using nCPAP after 2 months to 8 years of follow-up. One Hundred and thirty eight (79%) of these 174 patients used nCPAP for at least 4 h/night during >or= 5 nights/week, 82,1% of the conventional nCPAP (fixed pressure CPAP) group (n = 78) and 77,1% of the auto-CPAP group (n = 96). Therefore, including the 58 failures, only 59.5% of patients can be seen as compliant. There were no statistical differences between the fixed pressure CPAP and auto-CPAP users, and between the compliant and non-compliant users according to age, BMI, AHI and Epworth sleepiness scale (ESS). Auto-CPAP patients used significantly more cm H2O. The long-term compliance of nCPAP therapy has have increased only slightly since the introduction of the fixed pressure CPAP 25 years ago, in spite of many efforts to improve it. It seems that a plateau has been reached and that it is unrealistic to aim at a substantially higher compliance rate.

We analyzed the role of sleep position in obstructive sleep apnea syndrome (OSAS). The polysomnograms of 120 patients with sleep apnea syndrome were analyzed. We associated the apnea hypopnea index (AHI) of the supine position with the AHI of the other positions. Patients were stratified in a group of positional patients (PP) (AHI supine >or= 2 x AHI other positions) and a group of non-positional patients (NPP). In 55.8% of our patients, OSAS was position dependent. PP patients were significantly (6.7 years) younger. BMI and AHI were higher in the NPP group, but the difference was not significant. Level of obstruction in the upper airway (retropalatinal vs retrolingual vs both levels) as assessed by sleep endoscopy was not significantly different between the two groups. Total sleep time (TST) was equal in both groups, but the average time in supine position was 37 min longer in the PP group. This study confirms the finding that in more than 50% of patients, OSAS is position dependent. Apart from age, no patient characteristics were found indicating the position dependency. Overall AHI does not identify positional OSAS.

Should all patients with socially unacceptable snoring (SUS) undergo polysomnography, or is history-taking sufficient to identify the presence of obstructive sleep apnoea syndrome (OSAS)? Three hundred and eighty consecutive patients with SUS who underwent sleep registration were evaluated retrospectively to determine the predictive value of a history of apnoea or excessive daytime somnolence (hypersomnia). Of the patients analysed, 54% had OSAS, defined as an apnoea/hypopnoea index (AHI) of >15. This is higher than previously reported in the literature (46.7%). (Incidental) apnoea was reported by 337 (89%) of the patients, with a sensitivity of 0.92 and a specificity of 0.13. The predictive value--as related to the gold standard, i.e. sleep registration, of a negative test and of a positive test for OSAS is low (0.56 and 0.59, respectively). Hypersomnia was reported by 280 (74%) of the patients, with a sensitivity of 0.29 and a specificity of 0.72. The predictive value of a negative test and a positive test for OSAS is also low, 0.45 and 0.56, respectively. These data confirm that apnoea and hypersomnia in the history do not have a reliable predictive value of an obstructive sleep apnoea syndrome. We conclude that sleep registration is indicated in all patients with SUS, to rule out or confirm the presence of OSAS.