A double blind cross-over study of maximal expiratory flows and arterial blood gas tensions in normals, asthmatics and bronchitics after salbutamol and ipratropin.

8 normals, 8 asthmatics and 8 bronchitics inhaled comparable doses of ipratropin and salbutamol. Five different flow-volume parameters were measured before and at intervals from 3 to 360 minutes after inhalation, on a total number of 2880 maximal effort expiratory flow-volume curves. Arterial blood gas tensions were measured before and 60 minutes after inhalation. In all parameters a significant larger effect (p less than 0.05) of ipratropin was found in normals, but in different time intervals. The parameter FEV1 and MEF at 50% of FVC showed the largest effect of salbutamol during the interval from 3 to 60 minutes in the asthma patients. None of the parameters showed significant difference in drug effects in the bronchitis patients. The findings suggested a more peripheral action of ipratropin than of salbutamol in the normals. No significant change in gas tensions were found after inhalation in any of the three groups.