Could impulse oscillometry be an easy and practical test for differential diagnosis in healthy adults and patients with asthma and COPD?

Impulse oscillometry (IOS) is a type of oscillation technique that can detect pathological changes in small airways early. While spirometry is still normal in asthma and in patients who will have chronic obstructive pulmonary disease (COPD) in future, IOS can detect increased airway resistance with increased sensitivity in the early stages. The aim of this study is to evaluate IOS in healthy adults and patients with asthma and COPD. In this prospective and observational study; healthy adults without any airway disease and patients with asthma and COPD admitted to the pulmonology outpatient clinic were included. The IOS and spirometry tests were performed simultaneously in all 3 groups, and the test results and demographic data were recorded. Higher AX (kPa/L), Fres (1/s), lower X5 Hz (kPa/L/s), FEV1(L), FEV1/FVC%, MEF 25-75 (L), FEV3 (L), FEV3/FEV6%, FEV3/FVC6% values were found in COPD and asthma patients compared to healthy adults. The resistance difference between 5 and 20 Hz was unaffected in asthma patients whereas it was higher in COPD patients than in healthy adults. R5 Hz (kPa/L/s) was significantly higher in COPD patients than in healthy and asthma patients (P = .01). Our study results suggest that IOS shows significant variations among healthy adults, asthma patients, and those with COPD.