Acute administration of bronchodilators on exercise tolerance in treated COPD patients

Exercise intolerance is a major feature in patients with Chronic Obstructive Pulmonary Disease (COPD). Bronchodilators increase endurance time (ET) and reduce dynamic hyperinflation (DH). We evaluated whether a single-dose of salbutamol/ipratropium + flunisolide (BD + ICS), added on top of the regular treatment, may improve ET in COPD patients. In a single-blind randomized crossover pilot trial, nebulised BD + ICS or placebo (PL) was administered 30 min before a constant load cardiopulmonary test, in 22 moderate-to-severe COPD patients (FEV1: 53.9% pred). ET was the primary outcome measured. BD + ICS did not improve ET or VO2 peak with respect to PL. BD + ICS increased pre-test FEV1 and pre-test Inspiratory Capacity but did not modify DH. In a retrospective analysis, patients were divided in Improvers (N = 11) and Non-Improvers (N = 11) according to the difference in ET between BD + ICS and PL (>25 s). Improvers had a worst BODE index, a higher static hyperinflation and poorer Vd/Vt ratio at peak of exercise with respect to Non-Improvers. Improvers only had a significant increase from BD + ICS on pre-test FEV1 and IC. In conclusion, although a single-dose BD + ICS did not improve ET in COPD patients under regular treatment, a subgroup of more severe patients may have some benefit from that.