Are homecare High Flow Therapy devices equivalent to each other? Description on test bench.

Introduction: High Flow Therapy (HFT) aims to improve carbon dioxide (CO2) clearance from the anatomical dead space and providing comfortable, humidified airflow for chronic obstructive pulmonary disease (COPD) patients. This study aimed to compare the performance of three commercially available homecare HFT devices in terms of CO2 clearance and humidification capabilities. Methods: A dedicated test bench was developed to simulate the respiratory mechanics of a patient with severe COPD (R=25 cmH2O/L/s, C=66 mL/cmH2O). The devices were tested at various flow rates (15-60L/min) and temperature settings (31°C, 34°C, 37°C). Fractional carbon dioxide concentration in expired Air (FeCO2), Positive End Expiratory Pressure (PEEP), temperature, and humidity were continuously measured. Results: All devices demonstrated a flow-dependent reduction in FeCO2, confirming the CO2 clearance effect. Across devices, CO2 clearance was between 3.2-14.9% at 15L/min, 13.9-22.6% at 20L/min, 69.6-80.1% at 30L/min, and above 93.7% at 40 and 60L/min. A strong correlation was observed between increased flow rate and decreased CO2 levels across all devices. Variations in delivered temperature and humidity were observed between the devices. Regarding humidification, the choice of device proved to be the most significant factor. Conclusion: The in-vitro assessment confirms that all three tested HFT devices are effective at CO2 clearance in a simulated severe COPD patient model, with performance being highly dependent on the flow rate. The choice of device significantly influences the level of humidification provided. These findings can help clinicians make informed decisions when selecting HFT devices.