Bronchodilator response in asthma and COPD patients – additional spirometry parameters and their significance

<bold>Introduction:</bold> Bronchodilator response testing is performed in respiratory ill patients and reflects the airway structures and their possible changes after bronchodilator administration. Gold standard in the interpretation of the results are the established methods to assess the change in FEV1 and FVC and a change of >10% is considered a significant bronchodilator responsiveness (BDR). <bold>Aim:</bold> Since the BDR does not accurately differentiate between different types of airway diseases we aimed to determine whether additional spirometry parameters may contribute and have impact. <bold>Methods:</bold> We analyzed spirometry data from 60 hospitalized patients with a clinical diagnosis of asthma and COPD. A bronchodilator responsiveness testing was performed in all patients (33 female) aged 60.2±13.2 years. All patients completed slow and forced spirometry measurements including bronchodilator testing (BDT) with good efforts, complete exhalation, and FET ≥ 6 sec. <bold>Results:</bold> Among our group 25 patients had asthma and 35 patients were diagnosed with COPD. Applying the latest recommendation a significant bronchodilator responsiveness of >10% was found in 16 patients (27%). We measured and analyzed additionally the forced inspiratory flow (FIF) and the expiratory reserve volume (ERV) changes. A significant increase was found only in ERV but not always in combination with positive BDR. <bold>Conclusion:</bold> Bronchodilator response testing in clinical practice may be supported by the change in additional spirometry parameters. The reliability of the increased ERV found in different types of airway diseases needs further research.