%0 Journal Article %A Hiroshi Handa %A Jyongsu Huang %A Septimiu D. Murgu %A Masamichi Mineshita %A Noriaki Kurimoto %A Henri G. Colt %A Teruomi Miyazawa %T Assessment of central airway obstruction using impulse oscillometry before and after interventional bronchoscopy %D 2013 %R 10.4187/respcare.02094 %J Respiratory Care %P respcare.02094 %X Background: Spirometry is used to physiologically assess patients with central airway obstruction (CAO) before and after interventional bronchoscopic procedures but is not always feasible in these patients, does not localize the anatomic site of obstruction and may not correlate with patients’ functional impairment. Impulse oscillometry (IOS) may overcome these limitations. We aimed to assess the correlation of IOS measurements with symptoms and type of airway narrowing before and after interventional bronchoscopy. A secondary objective was to determine whether IOS parameters could discriminate between fixed and dynamic CAO. Methods: Twenty consecutive patients with CAO underwent spirometry, IOS, computed tomography (CT), MMRC Dyspnea Scale assessment and bronchoscopy before and after interventional bronchoscopy. The collapsibility index (CI) was calculated using morphometric bronchoscopic images on inspiration and expiration during quite breathing to distinguish fixed from variable CAO. The CI in variable CAO was defined as greater than 50% of the luminal area, whereas the CI in fixed CAO was defined as less than 50% of the luminal area. The degree of obstruction was analyzed by CT measurements. Results: After interventional bronchoscopy, all IOS measurements significantly improved, especially resistance (R5), which decreased from 0.67±0.29 kPa/(l/s) to 0.38±0.17 kPa/(l/s) (p<0.001), and reactance (X20), which increased from -0.09±0.11 to 0.03±0.08 (p<0.001). R5, R5-R20 and X5 changes but not spirometry measurements correlated with changes in MMRC Dyspnea Scale. The type of obstruction correlated with the MMRC Dyspnea Scale and showed distinct IOS measurements. Conclusions: IOS measurements correlate with improvement in symptoms post intervention. IOS might be useful to discriminating variable from fixed stenosis. %U https://rc.rcjournal.com/content/respcare/early/2013/07/16/respcare.02094.full.pdf