Comparative Effectiveness for Bronchodilator Responsiveness Testing

In a recent comparison study, researchers investigated the difference in bronchodilator response rate and efficacy for salbutamol administration via a nebulizer vs a metered dose inhaler with a spacer. The American Thoracic Society (ATS) recommends 4 separate 100 μg of short-acting β2-agonist salbutamol using a metered-dose inhaler (MDI) with a spacer. This study sought to identify the differences and efficacy between each modality to establish a consensus on bronchodilator responsive testing (BDR) protocol. Patients involved in this study were diagnosed with spirometry-confirmed chronic obstructive pulmonary disease (COPD).

Researchers analyzed data from December 1 2021 to June 30 2022 of patients who completed BDR testing at Xiangya Hospital. To be eligible for this study, patients had to be 18 or older, hav a spirometry-defined COPD diagnosis, moderate-to-severe spirometric abnormalities. Patients that had an upper airway obstruction, a past diagnosis of pneumonectomy, or a respiratory tract infection were disqualified from participation.

After sorting through the available participants, they predicted 240 patients were chosen. The primary goal for this analysis was to compare the forced expiratory volume (FEV) and the forced vital capacity (FVC) after and before BRT. They formed two hypotheses for this study: that the results would be identical between the 2 groups or the results would be significantly different. About 90 patients were in each group. The mean and standard deviation (SD) for FEV in the nebulizer group was 18 ± 10 mL, and in the inhaler group it was 16 ± 10 mL. For the FVC group, the SD was defined as 17 ± 10 mL for the nebulizer group and 14 ± 10 mL for the inhaler group. The alternative assumption was 2 mL and the SD was 10 mL. For results to be statistically significant, they established the change as anything 0.5 or over, and the statistical power was defined as 0.80.

In their results, they found that 894 out of the 972 patients fit the criteria for this study. Out of these patients, 578 received a bronchodilator via an MDI with a spacer, and 316 received it via nebulization. They found in the nebulization group that they had a higher proportion of severe impairment of baseline lung function, a higher number of smokers, lower FEV (33.3% vs 37.7%), more severe spirometric abnormalities (57.6% vs 41.5%), lower FVC (81.4% vs 83.8%) than the group with a spacer. They also found that FEV before nebulization was statistically significantly higher in the nebulization group than the spacer group (3.44% vs 2.97%). The nebulization group had a higher BDR rate than the spacer group as well (41.3% vs 30.0%).

“The ATS/ERS guidelines provide the recommended type and dose of bronchodilators for BDR testing. Meanwhile, the guidelines also proposed another dosing option. However, the impact of delivery techniques on BDR testing is yet to be identified,” the authors wrote. “To our knowledge, this is the first study to compare the effects of two delivery models (an MDI with spacer and nebulization) on the results of BDR testing.”

Salbutamol administration via a nebulizer was shown to be the preferrable option in comparison to salbutamol administration via a metered-dose inhaler with a spacer. However, patients must meet certain qualifications to be eligible for the nebulizer option and each individual is different.

Reference:

Lu R, Li Y, Hu C, et al. Nebulization versus metered-dose inhaler and spacer in bronchodilator responsiveness testing: a retrospective study. Therapeutic Advances in Respiratory Disease. 2023;17. doi:10.1177/17534666231214134