Localization of upper airway collapse during sleep in patients with obstructive sleep apnea.

The present study was conducted to determine the effects of body position and sleep state, as well as the effect of uvulopalatopharyngoplasty (UPPP) on the regions over which the upper airway (UA) collapses during sleep. To accomplish this goal, 18 male patients with obstructive sleep apnea (OSA) underwent overnight polysomnography with simultaneous monitoring of pressures in the posterior nasopharynx, oropharynx, hypopharynx, and esophagus. From the profile of pressures recorded in the UA and esophagus, the regions over which the UA collapses during apneas could be determined. The patients were 54 +/- 14 y of age and were grossly obese with a body mass index of 37 +/- 2 kg/m2. They had moderately severe OSA with a mean apnea plus hypopnea index of 62 +/- 8 per hour. During NREM sleep, 10 of the 18 (56%) patients had collapse confined to the velopharyngeal or retropalatal segment of the upper airway. The remaining 44% of the patients demonstrated collapse of the retroglossal segment of the oropharynx located caudal to the inferior margin of the soft palate. Upper airway collapse at the level of the hyoid bone was not observed during NREM sleep. Observations made during REM sleep in nine patients demonstrated that collapse occurred in a more caudal segment of the UA in seven patients during REM than during NREM sleep. The effect of sleep position was evaluated in 10 patients and found to have little affect on the extent over which the UA collapsed during sleep independent of sleep state. The effects of UPPP on regional UA collapse were evaluated in a small group of six patients.(ABSTRACT TRUNCATED AT 250 WORDS)