[Pharyngoscopic observation during sleep in patients with obstructive sleep apnea syndrome]

To analyse collapse sites of pharynx and their anatomical causes during sleep in patients with obstructive sleep apnea syndrome(OSAS), and compared with the results of Muller's maneuver.

The pharynges in 43 sleeping patients with OSAS were examined endoscopically. The area changes at each segment(velo-, oro- and hypopharynges) were calculated during the episodes of apnea. A site having greater than 75% narrowing of airway lumen was defined as a narrowing or obstructive site.

1. All patients had obstruction at velopharynx during asleep. Airway collapses at multiple sites in 79% of cases(28% at velo- and oropharynx; 21% at velo- and hypopharynges; and 30% at velo-, oro- and hypopharynges). 2. At each segment the anatomical factors causing obstruction were variable among patients. The common abnormalities were posterior displacement of soft palate or uvula, enlarged tonsil, thicken or posterior displacement of tongue base, collapse of pharyngeal wall, redundant mucosa or lateral bands of pharynx etc. 3. The positivity of pharyngeal obstruction was higher in this study as compared with of Muller's maneuver the latter was taken place while the patient was awaken. Comparison of the positive rate of the narrowing sites determined between sleep observation and Muller's maneuver in same patients: at velopharynx(100% vs 91%), at oropharynx (58% vs 42%) and at hyperpharynx (51% vs 28%).

Multiple obstructions in the pharynx are common. Examination of the pharynx during asleep may be more accurate then while the patient was awaken.