SAFETY OF ONE METHOD OF SPUTUM INDUCTION IN ASTHMATIC SUBJECTS

To assess the safety of sputum induction in asthmatic subjects, we con ducted a retrospective review of data from 351 sputum inductions in 78 subjects from our institution. The sputum induction protocol consiste d of baseline FEV1, pretreatment with albuterol 180 mu g, postbronchod ilator spirometry 15 min later, the induction procedure itself (inhala tion of 3% saline for 20 min), and postsputum induction spirometry. We found that sputum induction was usually well tolerated, although some subjects developed wheeze and dyspnea. Overall, 11 of the 78 subjects (14%) had a fall in FEV1 of greater than or equal to 20% from the pos tbronchodilator baseline (''excessive bronchoconstriction'') during th eir first sputum induction (range: -20 to -69%); no subject developed refractory bronchoconstriction requiring hospitalization or emergency room treatment. Only one of the 54 subjects (1.9%) with a baseline pre bronchodilator FEV1 > 80% had excessive bronchoconstriction, whereas 1 0 of the 24 subjects (42%) whose baseline FEV1 was less than or equal to 80% predicted did so. The change in FEV1 during sputum induction wa s significantly correlated with the baseline prebronchodilator FEV1% p redicted, the baseline postbronchodilator FEV1% predicted, the PC20 fo r methacholine, and the percentage of eosinophils in induced sputum. W e conclude that 180 mu g albuterol does not prevent excessive bronchoc onstriction in all asthmatic subjects undergoing sputum induction, esp ecially in asthmatic subjects with a low baseline FEV1. Pulmonary func tion should be monitored regularly during sputum induction in asthmati c subjects to monitor for excessive bronchoconstriction.