COMPUTERIZED-TOMOGRAPHY IN OBSTRUCTIVE SLEEP-APNEA - CORRELATION OF AIRWAY SIZE WITH PHYSIOLOGY DURING SLEEP AND WAKEFULNESS

Abstract

Pathophysiologic changes during sleep in patients with obstructive apnea are often associated with alterations in upper airway function during awake periods. To determine whether these functional changes are related to abnormal airway structure, computerized tomography (CT) was performed in 20 awake patients with obstructive apnea and in 10 control subjects. CT scan measurements of cross-sectional areas of the nasopharynx, oropharynx and hypopharynx in apneic patients were significantly reduced (P < 0.05) compared to those in the control subjects. Sites of obstruction varied and apparent airway occlusion occurred in 6 patients. Reduced pharyngeal size correlated with increased sleep-disordered breathing rates (P < 0.05), more severe nocturnal O2 desaturation (P < 0.05) and the presence of a saw-tooth pattern of flow-volume curves obtained during awake periods (P < 0.05). Structural upper airway narrowing is detectable with CT in awake patients with obstructive sleep apnea.