Efficacy of four high flow therapy devices in mucus clearance: A bench Study

High-Flow Therapy (HFT) is emerging as a promising treatment in home setting to improve outcomes in chronic respiratory patients with tracheobronchial clearance impairment. However, this clearance has been poorly documented. We used a mechanical lung (ASL5000, IngMarMedical) connecting 4 different HFT devices, 2 with a heated dedicated humidifier and two with a humidifier adapted to a non-invasive ventilation device. All were connected through a M-size cannula to a realistic upper airways mannequin and set at 30L/min, and 37°C for 8 hrs. We simulated over 6000 ventilatory cycles for each device across various respiratory dynamics using a "normal" lung model. We used an artificial polymer (POLYOXWSR Coagulant) to simulate secretions. Main parameters evaluated were mucus displacement (mm/min) toward the mouth or the lungs (positive and negative values, respectively) using a video system to subsequently analyze images (ImageJ software) and hygrometric characteristics, by absolute humidity (mgH2O/L) and temperature (°C). Dedicated devices significantly improved mucus displacement compared to spontaneous breathing (SB) and also compared to adapted devices (0.13±0.21 vs -0.04±0.02 vs 0.02±0.04mm/min; p<0.03). Regarding hygrometry, we similarly observed significant higher levels of mean absolute humidity (32.31±7.27 vs 29.83±1.73mgH2O/L; p<0.001) and mean temperature (32.0±3.47 vs 30.60±0.90°C; p=0.01) between dedicated and adapted devices. <fig><object-id>erj;64/suppl_68/PA2618/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>