Nasal High-Flow Therapy As an Adjunct to Exercise in Patients with Cystic Fibrosis: A Pilot Feasibility Trial.

Background: Exercise tolerance in people with CF and advanced lung disease is often reduced. While supplemental oxygen can improve oxygenation, it does not affect dyspnoea, fatigue or comfort. Nasal high-flow therapy (NHFT), thanks to its pathophysiological mechanisms, could improve exercise tolerance, saturation and dyspnoea. This study explores the feasibility of conducting a clinical trial of using NHFT in patients with CF during exercise. Methods: A pilot, open-label, randomized crossover trial was performed, enroling 23 participants with CF and severe lung disease. Participants completed two treadmill walking test (TWT) with and without NHFT at 24-48 h interval. Primary outcome was trial feasibility, and exploratory outcomes were TWT distance (TWTD), SpO(2), transcutaneous CO2, dyspnoea and comfort. Results: Recruitment rate was 2.4 subjects/month with 1.3:1 screening-to-randomization ratio. No adverse events caused by NHFT were observed. Tolerability was good and data completion rate was 100%. Twenty subjects (91%) were included in the exploratory study. Mean difference in TWTD on NHFT was 19 m (95% CI [4.8 - 33.1]). SpO(2) was similar, but respiratory rate and mean tcCO(2) were lower on NHFT (mean difference = -3.9 breaths/min 95% CI [-5.9 - -1.9] and -0.22 kPa 95% CI [-0.4 - 0.04]). NHFT reduced exercise-induced dyspnoea and discomfort. Conclusion: Trials using NHFT in patients with CF during exercise are feasible. NHFT appears to improve walking distance, control respiratory rate, CO2, dyspnoea and improve comfort. A larger trial with a longer intervention is feasible and warranted to confirm the impact of NHFT in training programmes for patients with CF. (C) 2021 The Authors. Published by Elsevier B.V. on behalf of European Cystic Fibrosis Society.