Neonatal resuscitation in resource-limited settings: titrating oxygen delivery without an oxygen blender

Objective: To test whether 4 commonly used self-inflating bags with a reservoir in situ can reliably deliver different oxygen concentrations (21%-100%) using a portable oxygen cylinder with flows of ≤5 L/min.

Study design: Four self-inflating bags (from Laerdal, Ambu, Parker Healthcare, and Mayo Healthcare) were tested to provide positive pressure ventilation to a manikin at 60 inflations/min by 4 operators. Oxygen delivery was measured for 2 minutes, combining oxygen flows (0.25, 0.5, 1, 5 L/min) and peak inspiratory pressures (PIPs 20-25, 35-40 cmH2O).

Results: Combinations (n=128) were performed twice. Oxygen delivery depended upon device, oxygen flow, and PIP. All self-inflating bags delivered mean oxygen concentrations of <40% with 0.25 L/min, regardless of PIP. Three self-inflating bags delivered ≤40% with flow 0.5 L/min at PIP 35-40 cmH2O, whereas all delivered >40% at PIP 20-25 cmH2O. With 1 L/min, 3 self-inflating bags delivered 40%-60% at PIP 35-40 cmH2O and all delivered >60% at PIP 20-25 cmH2O. With 5 L/min, all self-inflating bags delivered close to or 100%, regardless of PIP. Differences in oxygen delivery between self-inflating bags were statistically significant (P<.001) even when differences were not clinically important.

Conclusion: Self-inflating bags with a reservoir in situ can deliver a variety of oxygen concentrations without a blender, from <40% with 0.25 L/min oxygen flow to 100% with 5 L/min. The adjustment of oxygen flow may be a useful method of titrating oxygen in settings where air-oxygen blenders are unavailable.