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.
[Show abstract][Hide abstract] ABSTRACT: 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.
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).
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.
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.
Journal of Pediatrics 05/2014; 165(2). DOI:10.1016/j.jpeds.2014.04.020 · 3.79 Impact Factor
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