Acute effect of inhaled iloprost on exercise dynamic hyperinflation in COPD patients: A randomized crossover study.

Abstract

BACKGROUND AND OBJECTIVE\nWe tested whether the prostacyclin analog inhaled iloprost modulates dead space, dynamic hyperinflation (DH), and systemic inflammation/oxidative stress during maximal exercise in subjects with chronic obstructive pulmonary disease (COPD) who were not selected based on pulmonary hypertension (PH).\n\n\nMETHODS\nTwenty-four COPD patients with moderate-severe obstruction (age 59\xa0±\xa07 years, FEV1 53\xa0±\xa013% predicted) participated in a randomized, double-blind, placebo-controlled crossover trial. Each subject received a single nebulized dose of 5.0\xa0μg iloprost or placebo on non-consecutive days followed by maximal cardiopulmonary exercise tests. The primary outcome was DH quantified by end-expiratory lung volume/total lung capacity ratio (EELV/TLC) at metabolic isotime.\n\n\nRESULTS\nInhaled iloprost was well-tolerated and reduced submaximal alveolar dead-space fraction but did not significantly reduce DH (0.70\xa0±\xa00.09 vs 0.69\xa0±\xa00.07 following placebo and iloprost, respectively, p\xa0=\xa00.38). Maximal exercise time (9.1\xa0±\xa02.3 vs 9.3\xa0±\xa02.2\xa0min, p\xa0=\xa00.31) and peak oxygen uptake (17.4\xa0±\xa06.3 vs 17.9\xa0±\xa06.9\xa0mL/kg/min, p\xa0=\xa00.30) were not significantly different following placebo versus iloprost.\n\n\nCONCLUSIONS\nA single dose of inhaled iloprost was safe and reduced alveolar dead space fraction; however, it was not efficacious in modulating DH or improving exercise capacity in COPD patients who were not selected for the presence of PH.