Effects of Acute Long-acting Bronchodilation on Oxygenation and Peripheral Ventilation in COPD

The goal of this clinical trial was to compare the action of long-acting ß2-agonists (LABA-olodaterol) and muscarinic antagonists (LAMA-tiotropium) on tissue oxygenation in COPD considering their impact on proximal and peripheral ventilation and, eventually, on lung capillary volume. The hypothesis was that LABA would have a more peripheral effect than LAMA (due to the opposite gradient of their receptors) and better peripheral ventilation would result in a greater oxygenation. Before and after LABA (visit 1) and LAMA (visit 2) inhalation, COPD participants were asked to perform single-breath washout and forced oscillation tests, double diffusion technique and spirometry, while transcutaneous oxygenation was continuously recorded.