Nasal vs. oronasal mask during PAP treatment: a comparative DISE study.

Purpose: The present study evaluated the upper airway pattern of obstruction in individuals undergoing drug-induced sleep endoscopy (DISE) exam with positive airway pressure (PAP), and compared this effect through a nasal or oronasal mask.

Methods: Prospective study. Patients requiring PAP due to obstructive sleep apnea (OSA) were evaluated through DISE at three different moments: (1) a baseline condition (without PAP); (2) PAP treatment with a nasal mask; and (3) PAP with an oronasal mask at the same pressure. The conditions were compared intra-individually, following VOTE classification. A TOTAL VOTE score (the sum of VOTE scores observed for each anatomical site) was also applied to compare intra-individual results.

Results: Thirteen patients were enrolled in the study. All patients presented multi-level pharyngeal obstruction at baseline condition. In six patients, the pattern of obstruction differed according to the mask. Nasal mask significantly decreased the obstruction score when compared with baseline condition both in velum (P value < 0.05) and oropharynx regions (P value < 0.005). TOTAL VOTE score was also significantly lower during nasal mask evaluation when compared with basal condition (P value < 0.005). Remarkably, oronasal mask with the same pressure was not as effective as nasal masks. Obstruction levels observed at the tongue base or epiglottis levels were more resistant to PAP treatment.

Conclusions: Collapse in velum and oropharyngeal sites is more compliant to PAP than obstruction at lower levels of the pharynx, either with nasal or oronasal masks. Nasal mask is superior to prevent pharyngeal collapse than oronasal devices under the same pressure.