Application of impulse oscillometry to adult asthma with preserved lung function = Application of impulse oscillometry to adult asthma with preserved lung function

다국어 초록 (Multilingual Abstract)

Purpose: Spirometry has limitations in evaluating asthma with preserved lung function. Whereas, impulse oscillmetry (IOS) can detect not only airway resistance, but also reactance. Therefore, it is pressumed that IOS can help diagnosis of adult asthma with preserved lung function. However, the application of IOS to these patients have not been adequately investigated. Method:One thousand two hundred fifty-five patients with suspected asthma, who visited the Allergy and Asthma Clinic of Severance Hospital from 2015 to 2018, were enrolled. Patients performed pulmonary function test (PFT) and IOS. Among them, 117 patients were excluded due to parenchymal lung disease or chronic obstructive lung disease (COPD), or asthma- COPD overlap. Five hundred thirty-eight patients with asthma were excluded due to decreased lung function (predicted forced expiratory volume in 1 second < 80%). Six hundred asthma patients with preserved lung function were compared with 195 non-asthma patients. Then, among 600 asthma patients, asthma control status of 277 patients, who performed second PFT, were also analyzed. Result: Most IOS parameters were significantly higher in asthma patients than in non-asthma patients. Among the IOS parameters, Area of Reactance (AX) was the most appropriate parameter for predicting asthma (the area under a receiver operating characteristic curve (AUC) = 0.757). Optimal cut-off value for AX to diagnose asthma was 0.605. Its sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 52.4%, 91.6%, 91.4%, and 52.9%, respectively. Change rate of AX between 1st and 2nd IOS showed highest AUC (0.678) for predicting the stable asthma status. Conclusion: IOS is a useful utility for diagnosis and management of adult asthma with preserved lung function.