Influence of different extension-actuator tubes on the bronchodilation effect of a terbutaline sulfate aerosol.

The addition of a tube extension or of a pear-shaped spacer to a conventional metered-dose aerosol for delivering a bronchodilator drug, caused a slightly improved bronchodilation in 12 trained, adult patients with stable, reversible airways obstruction of moderate severity. Although statistically significant, the increase in bronchodilation effect does not appear to be clinically relevant in these patients. Continuous measurement of pulmonary resistance using the airflow interruption method did not reveal differences in the time of onset of the bronchodilation.