Change in Dynamic Hyperinflation After Bronchoscopic Lung Volume Reduction in Patients with Emphysema

Background and Purpose In patients with severe emphysema, dynamic hyperinflation is superimposed on top of already existing static hyperinflation. Static hyperinflation reduces significantly after bronchoscopic lung volume reduction (BLVR). In this study, we investigated the effect of BLVR compared to standard of care (SoC) on dynamic hyperinflation. Methods Dynamic hyperinflation was induced by a manually paced tachypnea test (MPT) and was defined by change in inspiratory capacity (IC) measured before and after MPT. Static and dynamic hyperinflation measurements were performed both at baseline and 6 months after BLVR with endobronchial valves or coils (treatment group) or SoC (control group). Results Eighteen patients underwent BLVR (78% female, 57 (43-67) years, FEV(1)25(18-37) %predicted, residual volume 231 (182-376) %predicted). Thirteen patients received SoC (100% female, 59 (44-74) years, FEV(1)25 (19-37) %predicted, residual volume 225 (152-279) %predicted. The 6 months median change in dynamic hyperinflation in the treatment group was: + 225 ml (range - 113 to + 803) (p <0.01) vs 0 ml (- 1067 to + 500) in the control group (p = 0.422). An increase in dynamic hyperinflation was significantly associated with a decrease in residual volume (r = - 0.439,p <0.01). Conclusion Bronchoscopic lung volume reduction increases the ability for dynamic hyperinflation in patients with severe emphysema. We propose this is a consequence of improved static hyperinflation.