Pilot Study of Oral Negative Pressure Therapy for Obstructive Sleep Apnea-Hypopnea Syndrome

Background: Although the continuous positive airway pressure is the gold standard therapy for patients with moderate to severe obstructive sleep apnea-hypopnea syndrome (OSAHS), there are several treatment options such as mandibular advancement devices, tongue-retaining devices, and nasal airway stent devices. Recently, newly developed intraoral pressure gradient therapy system, iNAP® Sleep Therapy System, was introduced as an alternative treatment for OSAHS patients. Purpose: This feasibility study explored the effectiveness of the iNAP® device for patients with mild to moderate OSAHS. Materials and Methods: The iNAP® device consisted of an oral interface, a tube set with a saliva container, and a negative pressure console. Negative pressure is introduced directly from the oral interface and the pressure pulls the tongue anteriorly, resulting in improving the obstruction or narrowing of the upper airway. A total of 5 male and 4 female patients with mild to moderate OSAHS, aged between 32 and 62, with 50.6 years ± 11.7 years were recruited in the study. Results: The baseline apnea-hypopnea index (AHI) was 17.2 events per hour ± 4.7 events per hour, while AHI with the iNAP® device was 12.7 ± 5.4 (p<0.01). Regarding the sleep architecture, a significant reduction in wakefulness after sleep onset (WASO) on the initial night of treatment from 97 min ± 50.0 min to 70.7 min ± 36.9 min (p<0.05) was observed; however, other sleep parameters were not. Conclusion: This study demonstrated that negative pressure therapy with the iNAP® device improved the apnea severity in patients with mild to moderate OSAHS, the degree of whose amelioration of AHI was marginal but significant. Although the number of patients recruited was small, this study is the first report on the effectiveness of the intraoral pressure gradient therapy.