High‐Flow Nasal Oxygen in Early Home Pulmonary Rehabilitation for Exertional Hypoxaemia: A Pilot Randomised Feasibility Trial

BACKGROUND: Patients with exertional hypoxaemia (EH) at hospital discharge face rapid deconditioning risks. However, early pulmonary rehabilitation (PR) is limited by exercise intolerance and access barriers. Optimal PR design for this group remains unclear. High-flow nasal oxygen (HFO) may alleviate EH, but its role in home-based PR is unexplored. We aimed to evaluate an early, intensive, home-based PR program and the integration of HFO during exercise training for EH patients post-hospitalisation. METHODS: In this pilot feasibility trial, EH patients across respiratory conditions were randomised to PR with HFO (HFO-PR) or PR alone (PR-only). Both groups commenced a three-week home-based PR program (two supervised, three self-directed sessions weekly) within 1 week of discharge. Feasibility was assessed using quantitative and qualitative measures. RESULTS: Fifty-two of 56 patients completed follow-up at 4 weeks. Overall PR program acceptance and uptake were 67% and 62%, respectively. Program completion was lower in the HFO-PR group (60%) compared to the PR-only group (89%), primarily due to reduced adherence to self-directed exercise sessions. Among COPD patients, the 1-min sit-to-stand test at 4 weeks improved by 4.6 repetitions in the HFO group and 5.3 in the PR-only group (adjusted difference in mean change -0.8, 95% CI -4.7 to 3.1). Qualitative findings revealed three themes: Transformations following the intervention, Receiving care and education at home, and Experiencing HFO system. Participants reported challenges with HFO during unsupervised exercise. CONCLUSION: Early home-based PR for post-hospitalisation EH patients is feasible and safe. However, the addition of HFO was associated with lower adherence, highlighting implementation barriers to address before further evaluation. TRIAL REGISTRATION: NCT05752370.