Assessment of tracheobronchomalacia in relapsing polychondritis using impulse oscillometry
Background: Airway involvement in relapsing polychondritis (RP) includes airway inflammation, airway narrowing and malacia. Systemic corticosteroid and immunosuppressive therapy does not always improve airway involvement making pulmonary interventions such as balloon dilation and stenting necessary. Impulse oscillometry (IOS) measurements can be safely performed in patients with airway involvement during quiet breathing before and after pulmonary intervention. Objectives: To confirm whether IOS can assess airway involvement in RP. Methods: Fifteen patients diagnosed with RP, based on McAdam9s criteria participated in this study. Airway disease including: airway narrowing, airway wall thickness, calcification and malacia were confirmed by computed tomography (CT). IOS was performed in all patients and respiratory resistance (Rrs) and respiratory reactance (Xrs) were calculated in frequency ranges of 5Hz increments from 5 to 35Hz. Results: Five patients developed into tracheobronchomalacia (TBM). R5-R20 and X5 showed a significant difference between patients with TBM and patients with only airway involvement (AI) (R5-R20:TMB 0.48±0.21kPa/(l/s), AI 0.15±0.27 kPa/(l/s), p Conclusions: IOS was useful in the evaluation of airway involvement in RP and R5-R20 and X5 were practical markers to differentiate patients with TBM.