Efficacy of Nasal High-Flow Oxygen Therapy in Chronic Obstructive Pulmonary Disease Patients in Long-Term Oxygen and Nocturnal Non-Invasive Ventilation during Exercise Training

High-flow oxygen therapy (HFOT) improves gas exchange and dead space washout and reduces the level of work required for breathing. This study aimed to evaluate pulmonary rehabilitation (PR) combined with HFOT in COPD patients treated with nocturnal non-invasive ventilation (NIV) and long-term oxygen therapy (LTOT). In particular, we sought to discover whether the addition of HFOT during exercise training could improve patients' performance, mainly with regard to their Six-Minute Walking Test (6MWT) outcomes, and reduce the exacerbation rates, periods of rehospitalization or need to resort to unscheduled visits. Thirty-one COPD subjects (13 female) who used nocturnal NIV were included in a randomized controlled trial and allocated to one of two groups: the experimental group (EG), with 15 subjects, subjected to PR with HFOT; and the control group (CG), with 16 subjects, subjected to PR without HFOT. The primary outcome of the study was the observation of changes in the 6MWT. The secondary outcome of the study was related to the rate of exacerbation and hospitalization. Data were collected at baseline and after one, two and three cycles of cycle-ergometer exercise training performed in 20 supervised sessions of 40 min thrice per week, with a washout period of 3 months between each rehabilitation cycle. Statistical significance was not found for the 6MWT distance (W = 0.974; p = 0.672) at the last follow-up, but statistical significance was found for the Borg scale in regard to dyspnea (W = 2.50; p < 0.001) and fatigue (W = 2.00; p < 0.001). HFOT may offer a positive option for dyspnea-affected COPD patients in the context of LTOT and nocturnal NIV.