Question of Study: In this study, we examined the oral airway resistance during wakefulness in different degrees of severity of OSAS (Obstructive sleep apnea) with Impulse Oscillometry and investigated whether these changes have any correlation with sleep apnea severity parameters.
Methods: All subjects who were admitted in sleep lab to undergo overnight sleep study were enrolled. Pulmonary function testing and measurement of oral airway resistance [resistance (R) and reactance (X)] by Impulse Oscillometry were done for every subjects. The average number of episodes of apnea and hypopnea per hour of sleep (the apnea-hypopnea index, AHI) were calculated. An AHI of 5 –29 represented mild/moderate OSAS and an AHI > 30 represented severe OSAS.
All parameters were compared between controls and mild/moderate and severe OSAS groups by using one way ANOVA methods.
Results: Patients with severe OSA had significantly lower FVC (P < .05) than healthy subjects; however, the values were within the normal range. Also these Patients had a higher resistance at 5 Hz (P < .05) and lower reactance than control(P < .05).
Conclusion: Impulse oscillometry data may be good predictor of OSA in Iranian patients with sleep apnea.
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