Study objectives: To compare conventional and self-adjusting nasal continuous positive airway pressure (nCPAP) therapy in patients with severe obstructive sleep apnea syndrome with respect to suppression of respiratory disturbances, quality of sleep, mean mask pressure, and patient compliance.
Design: Cohort study of consecutive patients with obstructive sleep apnea syndrome, single-blinded.
Setting: Clinical sleep laboratory in Germany.
Patients: Fifty patients (44 men, 6 women who ranged in age from 35 to 71 years) with polysomnographically confirmed severe obstructive sleep apnea syndrome (respiratory disturbance index [RDI], >20/h).
Measurements and interventions: After baseline polysomnography, patients were randomly treated with nCPAP either in conventional (group 1) or in automatically adjusting (group 2) mode. Three to 6 months after adjustment, all patients underwent polysomnography again. They also were examined with a portable monitoring device and received a questionnaire on subjective well-being and device evaluation.
Results: Anthropometric and respiratory data were comparable in both groups; body mass index had not changed significantly in the follow-up. RDI dropped by 91.5% (from 38.3±13.9/h to 3.6±4.4/h) in conventional and by 93.6% (from 35.5±9.6/h to 2.4±1.6/h) in self-adjusting mode (statistically not significant [NS]). Sleep efficiency decreased by 4.0% in conventional and increased by 2.0% in self-adjusting mode (NS). In both groups, normal sleep structure was largely restored. Mean mask pressure was 8.1±2.5 cm H2O in group 1 and 6.5±1.7 cm H2O in group 2 (p<0.01). Patient compliance in terms of nights per week of mask appliance was better in the self-adjusting mode (5.7±0.7 to 6.5±0.4; p<0.01).
Conclusion: Self-adjusting nCPAP demonstrates the same reliability in suppression of respiratory disturbances as fixed-mask pressure therapy. Sleep quality is slightly superior, patient compliance is highly significantly better.