The effect of bronchoscopic lung volume reduction on the bronchodilator response

Abstract

Background: Bronchoscopic lung volume reduction (BLVR) is a method of achieving lung collapse in severely emphysematous regions. One of the measures of success is the improvement in post-bronchodilator forced expiratory volume in the first second (FEV₁). The change in bronchodilator response (BDR) following BLVR is typically not reported, however, the changes in lung physiology that accompany endobronchial valve placement may impact aerosol drug delivery and alter the response to bronchodilators. We compared the BDR before and after BLVR to evaluate this effect.

Methods: We performed a retrospective study to analyze the change in BDR following BLVR. We included patients who underwent pulmonary function test (PFT) within 6 months of BLVR and confirmed complete lobar atelectasis. The pre-BLVR BDR for each patient served as the control, which was then compared to the post-BLVR BDR. The mean difference in the BDR before and after valve placement was determined. The comparison between pre- and post-BLVR means was performed using a t-test.

Results: A total of 35 patients were assessed for the study. Fifteen patients were excluded (due to valve removal, incomplete lobar collapse, and no pre- or post-BLVR PFT available). Of the 20 remaining patients, 14 had a positive BDR at baseline before BLVR. Following BLVR, 13 of the 14 patients demonstrated a non-significant increase in the BDR. The mean BDR for pre- and post-valve was 83.6 vs. 116.3 mL, respectively. The mean absolute increase in BDR following BLVR was 32.7 mL [95% confidence interval (CI): -32.5 to 97.8, P=0.31]. When including all 20 patients, the mean BDR pre- and post-BLVR was 47.5 vs. 86.5 mL, respectively, with a mean increase in BDR by 39 mL (95% CI: 22.3 to 100.3, P=0.21).

Conclusions: BLVR may improve the BDR in patients with complete lobar atelectasis.

Keywords: Bronchodilator response (BDR); bronchoscopic lung volume reduction (BLVR); chronic obstructive pulmonary disease (COPD); endobronchial valves.

Figure 1

Increases in BDR after BLVR. (A) Mean BDR pre- and post-valve for all patients and patients that demonstrated a positive BDR. (B) The mean improvement in BDR following BLVR for all patients and patients that demonstrated a positive BDR. BLVR, bronchoscopic lung volume reduction; BDR, bronchodilator response; FEV₁, forced expiratory volume in the first second.