Bronchodilator response (BDR)
One measurement according to the aforementioned criteria 15 min after
administration of 400 μg of salbutamol via a metered-dose inhaler with
spacer was selected for both IOS and spirometry. The spirometric BDR was
defined as positive when change of forced expiratory volume in one
second (FEV1) was ≥12% and/or ≥ 200 mL.