Inhaled albuterol powder for pulmonary function testing.

To assess the role of albuterol powder in testing for reversibility of airflow obstruction during routine pulmonary function testing, spirometric data from subjects with baseline FEV1/FVC less than 70 percent and FEV1 less than 80 percent predicted who received inhaled albuterol powder (n = 42) were compared with those who received isoetharine aerosol via metered dose inhaler (n = 49). Prebronchodilator lung function was comparable for the albuterol and isoetharine groups. With albuterol powder, 14 (33 percent) of 42 subjects showed reversibility of airflow obstruction (defined as a 15 percent or greater improvement in either FEV1 or FVC) as compared with 30 (61 percent) of 49 subjects with isoetharine aerosol. The significantly (p less than 0.01) lower rate of improvement with albuterol powder was especially prominent in subjects with moderate airflow obstruction (FEV1/FVC of 45 to 59 percent). These data do not support the substitution of inhaled albuterol powder for isoetharine aerosol in assessing for reversibility of airflow obstruction during routine pulmonary function testing.