High-Flow Oxygen Therapy (HFOT) during training in COPD with chronic respiratory failure (CRF): a multicentre randomized controlled trial

We compared in COPD with CRF undergoing training, HFOT (AIRVO2® Fisher&Paykel, (Flow/Temperature ranged 20-60 l/min/30-37°C respectively) vs oxygen Venturi Mask (V-mask) at iso-FiO2 on improving exercise tolerance. 171 patients were allocated to two groups; all used the same high-intensity exercise program (1 session/day for ≥ 20 sessions) with different oxygen device. BMI, spirometry and co morbidities have been collected. Baseline and after training exercise tolerance (Constant Work Rate Exercise Test, CWERT + 6-min walk test, 6MWT), respiratory (MIP/MEP) and biceps/quadriceps muscle strength, blood gases, Barthel Index and Barthel Dyspnoea Index, CAT and MRF-26 were measured. Patients’ satisfaction has been evaluated. 71 and 66 patients were analysed for HFOT and V-mask respectively being 15% and 24% the rate of drop-out. All variables improved after training in both groups with similar satisfaction. Comparing the two groups, only meters at 6MWT resulted statistically higher in HFOT group (p=0.029). HFOT group performed 153 seconds more than V-mask at CWERT, without statistical significance (p=0.057). Improvers (gain > 150 sec at CWERT) were 44% and 56% for V-mask and HFOT, respectively. FEV1% prd higher than 30% (OR 2.44, p=0.025) and higher baseline endurance time (OR 1.15, p=0.024) predicted improvers. Low BMI (OR 0.9298, p=0.038) predicted drop-outs. CWERT improvement was positively related to comorbidities (p=0.025) and CAT (p=0.031), while negatively to PaO2/FiO2 (p=0.04). We have confirmed the strong indication to training program in advanced COPD with CRF; HFOT used during training may further increase exercise tolerance.