Oxygen delivery using a neonatal self-inflating resuscitation bag: effect of oxygen flow

We evaluated the effect of oxygen (O₂) flow rate on the corresponding delivered fraction of oxygen (FiO₂) during positive pressure ventilation (PPV) when using a neonatal self-inflating bag (SIB).

Fifteen health care professionals administered PPV at a respiratory rate of 40 to 60 breaths per minute and at peak inspiratory pressures of 25 and 35 cm H₂O to a manikin by using a SIB with reservoir connected to an O₂ source equipped with a flowmeter (flow rates: 0-10 L/min). The FiO₂ corresponding to each flow rate was measured at the inflow to the facial mask for 60 seconds.

In total, 2520 FiO₂ data points were collected. At every O₂ flow rate, the FiO₂ gradually increased from time 0 seconds to time 60 seconds, both at 25 cm H₂O and at 35 cm H₂O. After 1 minute of PPV at 25 cm H₂O, the delivered FiO₂ was 31.5% ± 2.1% and 43.1% ± 3.1% at O₂ flow rates of 0.1 and 0.5 L/min, respectively. After 1 minute of PPV at 35 cm H₂O, the delivered FiO₂ was 29.4% ± 2.0% and 42.1% ± 4.6% at O₂ flow rates of 0.1 and 0.5 L/min, respectively. At all O₂ flow rates >5 L/min, the delivered FiO₂ was >85% and >95%, after 1 minute of PPV at 25 and 35 cm H₂O, respectively.

Delivered FiO₂ during PPV depends on 3 factors: oxygen flow rate, peak inspiratory pressures, and time elapsed. These data can be used to develop a scheme correlating the oxygen flow rate and the corresponding delivered FiO₂ when using a neonatal SIB.