On the selection day, the FEV, had to be at least 40 to 80 percent of the individual predicted normal value (based on the guidelines for standardized lung function testing of the European Community for Coal and Steel). As criterion of reversibility, this FEV, had to increase by at least 15 percent after the inhalation of 200 jig of salbutamol from an MDI. Finally, as criterion of stability, the basal FEV, value was not permitted to vary by more than 15 percent on the two study days. Various patients were excluded from the study, such as those with exercise asthma (spirometer asthma), pregnant or lactating women, patients who had recently suffered a respiratory tract infection, those who had hypertension, coronary artery disease, cardiac rhythm disturbances, heart failure, and ST/T segment abnormalities in the ECG.
Moreover, all patients with insulin-dependent diabetes mellitus, recent abnormalities of laboratory values, patients with excessively low serum potassium values (<3.5 mmol*L’) on the day of selection, and those who were known to react abnormally to sympathomimetics were all excluded. Meth-ylxanthine therapy had to be stopped for at least 24 hours before the start of the study period. Beta-mimetic therapy, apart from the study Canadian drugs, had to be stopped 24 hours before the study day if given by mouth, and 8 hours before if given by aerosol as was the case for inhaled anticholinergics.