LAUSR

ABSTRACT Background: To better understand the changes in pulmonary physiology related to asthma severity following bronchoscopy, we performed scheduled pre- and post-procedure spirometry on subjects undergoing bronchoscopy in our research program. Methods: Control subjects and asthma subjects were recruited for bronchoscopy. On the day of bronchoscopy, subjects underwent spirometry pre-bronchoscopy and then up to three sets within 2 hour following the completion of bronchoscopy. A subset of patients had a second bronchoscopy after 2 weeks of treatment with oral prednisolone (40mg daily). Results: A total of 92 subjects had at least one bronchoscopy (12 control subjects, 56 nonsevere asthma (NSA), 24 severe asthma (SA)). The SA and NSA groups had similar decreases in forced expiratory volume in 1 second (FEV1) (−20±13% vs.−19±16%, p = 0.92) and forced vital capacity (FVC) (−20±12% vs.−20±14%, p = 0.80), but no change in FEV1/FVC ratio. The control and NSA group had more rapid recovery of both FEV1 and FVC by 2 hour compared to the SA group (p = 0.01). In the subset of 36 subjects (22 NSA, 14 SA) who underwent a second bronchoscopy following the administration of oral prednisolone for 14 days, steroids resulted in more rapid recovery of lung function (p < 0.04). Conclusion: Following bronchoscopy the lung function of NSA subjects recovered more quickly than SA subjects. Treatment with oral corticosteroids was associated with a quicker recovery of FEV1 which suggests an inflammatory mechanism for these changes in lung compliance.