**9.3. Nasal continuous positive airway pressure (nCPAP) device treatment**

It is a device which has a small air pump connected to either a sealed face or nose mask. The device opens the pharyngeal airway and prevents the soft tissues from collapsing and blocking the airway. It is the gold standard treatment option for moderate to severe OSAS cases, and the success rate is about 75%. However, patient compliance is poor because of the pump noise, the irritation of nasal mucosa because of the airflow to the nose, xerostomia, and poor retention. The patient non-compliance ratio was reported to range from 46 to 83%. The ordinary usage of nCPAP device for 4–6 weeks decreases the volume of the tongue and increases the pharyngeal volume. Inclusion criteria for nCPAP therapy are moderate and severe OSAS patients with AHI score greater than 20, mild OSAS patients with AHI scores between 10 and 20 but has excessive daytime sleepiness and cardiopulmonary or cerebrovascular risks, anatomical-based OSAS patients whose medical health condition is inappropriate to surgical treatment, and mild-to-moderate OSA patients who have failed behavioral modification therapy and unable to tolerate oral appliances [1–10, 16, 17].
