Article Text
Abstract
Introduction Patients recovering from severe acute exacerbations of COPD (AECOPD) have a 30-day readmission rate of 25%. High-flow therapy (HFT) improves mucociliary clearance, dead space washout and pulmonary mechanics in stable COPD. This study aimed to determine the feasibility of a Phase III randomised control trial (RCT) of home HFT to improve clinical, patient-reported and physiological outcomes following severe AECOPD.
Methods Mixed-methods feasibility RCT (quantitative primacy, concurrently embedded qualitative evaluation) (NCT03899558). Consecutive hospitalised AECOPD patients, aged 40–80, BMI≤35kg/m2, PaCO2≤7kPa, not requiring acute or home mechanical ventilation were randomised to receive usual care or additional home HFT and received weekly home-based follow-up. Semi-structured interviews were performed in week 4. Feasibility outcomes were recruitment, protocol adherence, device acceptability. Progression criteria: ≥40% of eligible patients randomised, complete data in >70%, no device-related serious adverse events (SAE).
Results Feasibility: Between June 2019–March 2020, 263 patients screened, 45 eligible, 15 declined, 18 (40%) randomised (figure 1). Mean±SD/median(IQR) age 69±5, 44% female, BMI 22.5±5kg/m2, FEV132±12%. Discharge HFT settings: 37°C, 25–30L/min. Adherence to assessments, questionnaires and parasternal EMG (EMGpara) 100%, spirometry 91%, complete data in 83%. By week 4, HFT use was 2.4 hours/day. There were no device-related SAE. Four themes relating to HFT acceptability were identified: technical, daily routine, impact on symptoms, sensory-affective influence. Facilitators to use included device simplicity and sputum clearance, barriers were warmup time and excessive flow/temperature. Exploratory: The HFT group had a 59% risk of 30-day re-exacerbation/readmission (OR 0.41, 95%CI 0.05–3.31). Breathlessness (mBorg) and neural respiratory drive index (EMGpara%max.bpm) improved in the HFT group (admission to week 4 change (Δ) and repeated measures ANOVA significance: Δ-5(-6 to -3),p<0.001 and Δ-214±95%.bpm,p=0.02, respectively), not controls (Δ-2±3,p=0.25 and Δ-207±299%.bpm,p=0.10, respectively). Health status (COPD assessment test) improved in the HFT (Δ-12±5,p<0.001) and control groups (Δ-12±7,p=0.01). Total sleep time fell in the HFT group (Δ-84±97min,p=0.02). There were no changes in physical activity.
Conclusions This study design was determined to be feasible, with all progression criteria met. A Phase III RCT is warranted to evaluate the effects of home high-flow therapy on 30-day re-exacerbation/readmission and patient-reported and physiological outcomes in this high-risk cohort.