Small airway resistance in obese and nonobese patients with obstructive sleep apnea syndrome using impulse oscillometry

Background/aim: There is limited information on the pathologic changes in the small airways among obese and nonobese patients with obstructive sleep apnea syndrome (OSAS). Impulse oscillometry (IOS) measures airway resistance and reactance independently of patient effort. This study aimed to compare airway resistance in small airways using IOS between obese and nonobese patients with OSAS. Materials and methods: In this real-life cross-sectional study, demographic information was collected from obese and nonobese subjects diagnosed with moderate and severe OSAS without any other underlying diseases. Spirometry and IOS measurements were conducted, and the values of both groups were statistically analyzed. Results: The nonobese group had a mean age of 45.6 +/- 11.7 years (median 45), while the obese group had a mean age of 48.4 +/- 9.5 years (median 47.5). The mean body mass index (BMI) for the nonobese group was 26.2 +/- 2.1 kg/m(2) (median 27 kg/m(2)), and for the obese group, it was 35.6 +/- 6.4 kg/m(2) (median 33 kg/m(2)). Statistically significant differences were observed between the two groups in R5 - R20 percentage, reactance area (AX), and resonant frequency (Fres) values (p < 0.05). Conclusion: Among obese OSAS patients, there is an increase in resistance in small airways as indicated by IOS values. IOS shows promise as a potential screening tool for diagnosing OSAS.