Figure 2:

Closed mouth models’ tracheal pressures measured at baseline (spontaneous breathing without flow) and at increasing flows provided with two HFNC systems: Fisher and Paykel Optiflow and Vapotherm Precision Flow. Each data point represents the average of three runs at each flow, with error bars representing standard error between these runs. The data points are fitted with a quadratic, best fit trendline, except preterm neonate Vapotherm system, which has a linear trendline. The horizontal dashed line represents current guidelines for CPAP initiation pressure.