Abstract
Background: Bronchoscopic lung volume reduction with endobronchial valves(BLVR) in emphysema improves ventilatory mechanics and in exercise capacity. We aimed to examine the effect of BLVR on oxygen uptake(VO2) kinetics in emphysema patients. We hypothesise that reduction of gas trapping would accelerate VO2 kinetics.
Methods: 5 male emphysema patients(age:63.8±8.1 y;FEV1 %predicted:29.2±7.6)who showed a reduction in residual volume(RV)>350ml post BLVR and were able to exercise on cycle ergometer at 75% peak work load for >4 min pre and post BLVR were selected for VO2 kinetics analysis. VO2 dynamics were quantified from the rise time(Tau).
Results: Post BLVR treatment, there was a 19% reduction in the RV(1.2±0.8 L), 29% increase in FEV1 (0.24±0.19 L) and 11% increase in TLCO(0.5±0.8). Exercise time increased by 45%(88 ±236 s) however there was no significant change in tau (41.7±13.3vs.39.5±7.8 s; p=0.78). 1 subject with 2.3L reduction in RV, 0.46L increase in FEV1 and an increase in exercise time of 329s showed faster VO2 kinetics post BLVR(tau: 40.8vs59.4 s).
Conclusions: BLVR improved lung function and presumably V/Q mismatch and O2 delivery without acceleration in VO2 kinetics in the group as a whole. This could be a result of poor muscle oxidative capacity and compromised ability to extract O2 despite improved delivery.
- © 2013 ERS