ABSTRACT
BACKGROUND AND OBJECTIVES: The aim of this study is to identify differences in polysomnographic findings according to the upper airway obstruction level in patients with obstructive sleep apnea (OSA). SUBJECTS AND METHOD: Eighty-four patients with OSA were included in this study. Every patient underwent polysomnography (PSG) and upper airway pressure measurement using a four-sensor catheter simultaneously. The catheter was positioned at the posterior nasal cavity, uvula tip, tip of the epiglottis, and mid-esophagus level, which was inserted through the nasal cavity down to the esophagus. The patients were categorized into two groups of single site obstruction and multi-site obstruction. RESULTS: Twenty-one patients showed single site obstruction and sixtythree patients showed multi-site obstruction. Apnea-hypopnea index, apnea index, and minimal oxygen saturation showed statistically significant differences between two groups. There was no difference in bony mass index (BMI). CONCLUSION: Upper airway pressure measurement can be a method to evaluate the upper airway obstruction site. This study shows that OSA patients with multisite obstruction have severer sleep apnea than those with single site obstruction.