Maximal Expiratory Flows and Forced Vital Capacity in Normal, Asthmatic and Bronchitic Subjects after Salbutamol and Ipratropium Bromide

Abstract

A total of 2,880 maximum expiratory flow-volume curves were performed in a controlled double-blind cross-over examination designed to evaluate the bronchodilating effects of two different nebulized doses of salbutamol (1.75 and 0.875 mg) and ipratropium bromide (0.175 and 0.0875 mg) inhaled by 8 normal, 8 asthmatic, and 8 bronchitic subjects. FEV₁, FVC, and flows at 50% FVC and at three fixed volumes below TLC have been measured over a period of 6 h on the maximum expiratory flow-volume curve. In the normal subjects, salbutamol seems to have a smaller bronchodilating effect than ipratropium bromide both at high and low lung volumes. After salbutamol the average initial FEV₁ increased from 4.0 to 4.3 liters, whereas after ipratropium bromide it increased to 4.4 liters. In our asthmatic patients the initial response to salbutamol was much larger than to ipratropium bromide. After salbutamol FEV₁ increased from 1.8 to 2.7 liters in 60 min, whereas after ipratropium bromide it increased to 2.4 liters in 120 min. In our bronchitic patients the difference between the two drugs seems to be very small. After both drugs FEV_t increased from 1.6 to 2.1 liters. The choice of drug for treatment of the condition would then depend on how well the individual patients tolerate the two drugs.