Comparison of the pharyngeal pressure provided by two heated, humidified high-flow nasal cannulae devices in premature infants

Aims: This study aims to determine if there is a difference in the pharyngeal pressure, measured as a surrogate for continuous positive distending airway pressure, delivered to premature infants between two commonly used heated, humidified high-flow nasal cannulae (HHHFNC) devices: Fisher & Paykel Healthcare HHHFNC and Vapotherm 2000i. Methods: Pharyngeal pressure measurements were taken from stable premature infants receiving HHHFNC for respiratory support. Flow rates of 2-8 L/min were studied. Results: Nine infants had pharyngeal pressure measurements recorded with both HHHFNC devices at flow rates of 2-8 L/min. There was no difference in pharyngeal pressures recorded between devices at flow rates of 2-6 L/min; measured pressure was linearly associated with flow (R-2 = 0.9). At flow rates of 7 L/min, Vapotherm delivered a mean (standard deviation) pharyngeal pressure of 4.7 (2.2) cmH(2)O compared with 4.23 (2.2) cmH(2)O by the Fisher & Paykel device (P = 0.04). At a flow of 8 L/min, the mean pharyngeal pressure via Vapotherm was 4.9 (2.2) cmH(2)O compared with 4.1 (2.3) cmH(2)O with the Fisher & Paykel device (P = 0.05). Conclusions: Both HHHFNC delivered similar pharyngeal pressures at flow rates of 2-6 L/min. The pressure limiter valve of the Fisher & Paykel device attenuated the pharyngeal pressures at flows of 7 and 8 L/min. Vapotherm trended towards higher delivered pharyngeal pressure at flow rates 7 and 8 L/min, but the clinical significance of the difference remains unclear.