Home nasal high-flow following severe COPD exacerbation: a mixed-methods feasibility randomised controlled trial

Home nasal high flow (hNHF) may improve outcomes in hypoxaemic COPD patients. Those recovering from acute exacerbations (AECOPD) are at high risk of readmission or re-exacerbation. We conducted a mixed-methods randomised controlled trial to determine the feasibility of a phase III trial evaluating the effect of hNHF on 30-day readmission following severe AECOPD. Hospitalised COPD patients were randomised to receive usual care or additional hNHF (ISRCTN15949009) following discharge. Feasibility was assessed by recruitment, protocol adherence and acceptability. Progression criteria: ≥40% of eligible patients randomised, complete data in ≥70%, no hNHF-related SAEs. Clinical, patient-reported and physiological outcomes were measured weekly for 30 days and semi-structured interviews performed in week 4. Jun 2019-Mar 2020, 263 screened, 46 eligible (commonest exclusions: age, respiratory failure), 15 declined, 20 recruited, 17 completed follow-up (8 hNHF, 9 controls). Mean±SD age 69±5, 59% male, BMI 23±5kg/m², FEV₁ 32±12%. Complete data in 83%. Adherence to home visits, questionnaires and parasternal EMG (EMG_para) 100%, spirometry 91%. hNHF use 2.4 hours/day, no SAEs. 30-day re-exacerbation/readmission in 5 controls and 2 hNHF patients. At day 30, CAT score improved in controls (31 to 19, p=0.01) and hNHF (33 to 21, p<0.001). Resting mBorg dyspnoea and EMG_para improved in the hNHF (p<0.001, p=0.045), not control arm (p=0.25, p=0.20). Facilitators to hNHF were improved sputum clearance and reduced breathlessness, setup time was a barrier. This study indicates that a phase III trial is feasible and should be performed in this group at high risk of poor post-hospital outcomes.