Domiciliary nasal high flow therapy for breathlessness; chronic obstructive pulmonary disease (COPD)

<bold>Introduction/Aim:</bold> Nasal high flow therapy (NHF) is an established treatment for acute respiratory failure, however data regarding benefits of domiciliary NHF in people with COPD are limited. This phase II trial aimed to determine feasibility and acceptability of NHF for people with COPD and severe breathlessness. <bold>Methods:</bold> A single-arm, open label, mixed methods, phase II trial of an 8-day, air-only NHF intervention in adult patients with COPD and severe breathlessness not requiring domiciliary oxygen therapy. <bold>Results:</bold> 15 participants were enrolled (mean age 73.6; 40% women; mean FEV1 41% predicted; mean DLco 43% predicted; mean mMRC 3.7). 87% completed the trial with 54% keeping the device, 20% reported continued use at 8 months post-trial. Adherence varied, with average daily usage higher amongst participants who kept the device compared to those who returned it (6.8±2.3h vs 3.4±3.7h). No significant changes in mean difference at day 8 relative to baseline were detected for worst breathlessness (0.7±1.2 (mean±SD), p=0.109), dyspnoea mastery (0.3±0.6, p=0.176) or fatigue (0.0±2.4, p=1.00). No significant adverse events were reported. Qualitative interviews demonstrated subjective improvements in breathlessness, dry mouth, and sputum production for some, whilst others found NHF uncomfortable. Fear of NHF dependence and concerns regarding long-term running costs were reported. <bold>Conclusions:</bold> Domiciliary NHF was a feasible intervention, with varied adoption and acceptability. Trial implementation outcomes may have affected preliminary effectiveness outcomes. Further research is required to determine what role domiciliary NHF may have for people with COPD and severe breathlessness.