Treatment of obstructive sleep-disordered breathing with positive airway pressure systems

Abstract

Positive airway pressure systems are widely used to treat patients with moderate-tosevere obstructive sleep-disordered breathing. The application of stable continuous positive airway pressure (CPAP) via the nose (nasal CPAP) has been the mainstay of treatment since the early 1980s. For treatment to be effective, the pressure level must be fine-tuned to restore patency of the individual patient's upper airway.Currently, there is ongoing controversy concerning which outcomes to observe when adapting the pressure level, and which methods to use for pressure adaptation. Adjusting the pressure level to control apnoeas and hypopnoeas is one major objective, but may not be sufficient to restore normal sleep. Evidence is available that elimination of inspiratory flow limitation leads to better results.In recent years, it has become evident that the use of empirically set CPAP or automatic CPAP devices parallel the clinical results obtained with the classical approach of manual CPAP titration. A striking and still unexplained paradox lies in the fact that automatic CPAP devices perform very differently on the bench, but still yield satisfactory results on several clinical outcomes, e.g. control of sleep-related respiratory disturbances, restoration of good sleep quality and daytime alertness. Understanding the functioning of automatic CPAP devices can prove difficult, as the mode of operation is usually not disclosed by the manufacturers.At present, it is impossible to make any scientifically sound statement on the appropriateness of using automatic continuous positive airway pressure devices for the routine treatment of patients with obstructive sleep-disordered breathing. For this purpose, convincing results of phase I-III clinical trials are needed.

Response of automatic continuous positive airway pressure devices in a normal subject

“…In other words, they have never been applied to normal subjects [8]. If the assumptions behind these devices are correct, an autoCPAP applied to a normal subject should detect no abnormality in breathing and therefore its positive pressure should remain at the minimum level (4 cmH 2 O in general) necessary to wash out the expired CO 2 from the mask.…”

Evaluation eines neuen Algorithmus zur automatischen CPAP-Therapie beim obstruktiven Schlafapnoe-Syndrom

“…In einer Metaanalyse konnte bestätigt werden, dass sich ± bei gleicher Effektivität ± unter APAP der mittlere therapeutische Druck im Vergleich zur Therapie mit einem fixen CPAP-Druck um 2,2 cm H 2 O senken lässt [11]. Dennoch konnte bei unselektionierten OSAS-Patienten keine höhere Compliance durch eine automatische CPAP-Therapie erzielt werden, sodass die Entscheidung für diese Therapieform individuell getroffen werden muss [23]. Die entscheidende technische Herausforderung der automatischen CPAP-Therapie besteht in der zuverlässigen Erkennung respiratorischer Störungen und in der exakten Differenzierung zwischen obstruktiven und zentralen Ereignissen auf der einen Seite und Artefakten auf der anderen Seite.…”

Respiratory somnology: a clinical update

“…In the second article, PEVERNAGIE et al [2] deal with the application of stable CPAP via the nose (nasal CPAP), as it has been the mainstay of treatment for more than two decades in obstructive sleep apnoea patients. As there is poor treatment compliance and/or refusal in a large proportion of CPAP-treated patients, BOUDEWYNS et al [3], in the third article, describe the selection of patients for the different conservative (oral appliances) and surgical treatment modalities (upper airway surgery by soft tissue resection (uvulopalatopharyngoplasty, etc.)…”