Nasal Cannula, CPAP, and High-Flow Nasal Cannula: Effect of Flow on Temperature, Humidity, Pressure, and Resistance

Abstract Background: Delivery of warm, humidified, supplemental oxygen via high-flow nasal cannula has several potential benefits; however, the high-flow range may not maintain humidification and temperature and in some cases may cause excessive expiratory pressure loading. Objective: To compare the effect of flow on temperature, humidity, pressure, and resistance in nasal cannula (NC), continuous positive airway pressure (CPAP), and high-flow nasal cannula (HFNC) in a clinical setting. Methods: The three delivery systems were tested in the nursery using each instrument's recommended specifications and flow ranges (0–3 L/min and 0–8 L/min). Flow, pressure, temperature, and humidity were measured, and resistance was calculated. Results: For all devices at 0–3 L/min, there was a difference (p CPAP 34.5°C > HFNC 34.0°C), humidity (HFNC 82% > CPAP 77% > NC 57%), pressure (HFNC 22 cmH2O > NC 4 cmH2O > CPAP 3 cmH2O), and resistance (HFNC 636 cmH2O/L/sec > NC 270 cmH2O/L/sec > C...