Comparison of Actual Performance in the Flow and Fraction of Inspired O(2) among Different High-Flow Nasal Cannula Devices: A Bench Study

BACKGROUND: High-flow nasal cannula (HFNC) oxygen therapy has been recommended for use in coronavirus disease 2019 (COVID-19) patients with acute respiratory failure and many other clinical conditions. HFNC devices produced by different manufacturers may have varied performance. Whether there is a difference in these devices and the extent of the differences in performance remain unknown. METHODS: Four HFNC devices (AIRVO 2, TNI softFlow 50, HUMID-BH, and OH-70C) and a ventilator with an HFNC module (bellavista 1000) were evaluated. The flow was set at 20, 25, 30, 35, 40, 45, 50, 60, 70, and 80 L/min, and the FiO(2) was set at 21%, 26%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 80%, and 90%. Then, one side of the cannulas was clipped to simulate the compression, bending, or blocking of the nasal cannulas. The flow and FiO(2) of the delivered gas were recorded and compared among settings and devices. RESULTS: The actual-flow and actual-FiO(2) delivered by different settings and devices varied. AIRVO 2 had superior performance in flow and FiO(2) accuracy. bellavista 1000 and OH-70C had good performance in the accuracy of actual-flows and actual-FiO(2,) respectively. bellavista 1000 and HUMID-BH had a larger flow range from 10 to 80 L/min, but only bellavista 1000 could provide a stable flow with an excessive resistance up to 60 L/min. TNI softFlow 50 had the best flow compensation and could provide sufficient flow with excessive resistance at 20–50 L/min. CONCLUSIONS: The variation in flow, FiO(2) settings, and devices could influence the actual-flow and actual-FiO(2) delivered. AIRVO 2 and OH-70C showed better FiO(2) accuracy. TNI softFlow 50, bellavista 1000, and HUMID-BH could lower the risk of insufficient flow support due to accidental compression or blocking of the cannulas. In addition, ventilators with HFNC modules provided comparable flow and FiO(2) and could be an alternative to standalone HFNC devices.