Impulse Oscillometry May Be Useful in Evaluation of Bronchiectasis Severity and Prediction of Airway Reversibility.

Abstract BackgroundImpulse oscillometry (IOS) can be used to evaluateairway impedance in patients with obstructive airway diseases. Previous studies have demonstrated that IOS parameters differ betweenbronchiectasis patients and healthy controls. This study aims to explore the usefulness of IOS in assessing disease severity and airway reversibility in bronchiectasis.MethodSeventy-four patients with non-cystic fibrosis bronchiectasis who visited our Respiratory Medicine outpatient clinic were consecutively recruited. Spirometry, plethysmography and IOS tests were performed. Patients were stratified into mild, moderate and severe disease according to Reiff, Bhalla, BSI, FACED, and BRICS scores. Airway reversibility was measured by bronchodilation test (BDT) and the result was classified as positive or negative.. ROC curves of IOS parameters was used to assess the usefulness of IOS parameters in predicting airway reversibility. Correlations between the IOS, spirometric lung function and bronchiectasis severity parameters were analysed.ResultsMany IOS parameters, such as airway resistance at 5Hz (R5), small airways resistance (R5–R20), total airway reactance (X5), resonance frequency (Fres), total airway impedance at 5Hz (Z5), and peripheral resistance (Rp) increased with increased bronchiectasis severity according to the FACED, BSI and Reiff scores. Large airway resistance (R20) and central resistance (Rc) were not significantly different among groups with differentbronchiectasis severity. The difference between R5 and R20 (R5-R20) showed 81.0% sensitivity, and 69.8%specificity in predicting the airway reversibility in bronchiectasis with AUC of 0.794 (95%CI, 0.672-0.915).ConclusionIOS measurements are useful indicators of bronchiectasis severity and may be useful for predicting the airway reversibility.