Abstract

Study objectives: To compare the early bronchodilator responses of salbutamol (S), ipratropium bromide (IB), and the combination of salbutamol and ipratropium bromide (S-IB) on spirometric reversibility testing and to determine their role in the differential diagnosis in patients with asthma or COPD.

Design: Prospective, randomized, single blind

Methods: The effects of S, IB, and S-IB on baseline spirometric parameters were evaluated in 47 patients with stable asthma and 32 patients with stable COPD at 30th min in three separate test days after the washout periods. Absolute increments (D) of FVC, FEV1, MMEF, PEFR and change as a percentage of prebronchodilator value (% initial) were recorded and compared both between patient groups and drugs. Number of the reversibility positive patients according to ATS criteria were evaluated for each drug.

Results: All spirometric parameters in asthmatic patients were significantly higher than COPD patients at basaline and 30th min in three separate test days. D and % initial values of FEV1, D and % initial values of MMEF after the S and S-IB inhalations were significantly higher than IB in asthmatic patients. No significant difference was detected among drugs in COPD patients. Average DMMEF values of all drugs in asthma patients were significantly higher than whose in COPD patients. FEV1 % initial and FVC % initial values of S, IB, and S-IB were significantly higher in COPD patients. As for the ratio of reversibility positive patients in COPD group, there was no significant difference between the study drugs. However, S-IB seemed to be superior in asthma group for detecting reversibility positive patients.

Conclusions: IB failed to identify spirometric reversibility in asthmatic patients. Therefore,b agonist or combination of bagonist- anticholinergic agent should be used on early reversibility test for the differantial diagnosis of asthma and COPD.