Title : Oxygen delivery using neonatal self-inflating bags without reservoirs Running title : Oxygen delivery by self-inflating bags

Background Guidelines recommend avoiding excessive oxygen administration during neonatal resuscitation. Recent studies have suggested that oxygen titration can be achieved using a self-inflating bag. However, only a few data have supported the effectiveness of resuscitators used in neonatal ventilation. A cc ep te d A rt ic le This article is protected by copyright. All rights reserved. The aim of this study is to determine the amount of oxygen delivered using several brands of neonatal self-inflating resuscitation bags without reservoirs under several conditions, including different oxygen flow rates, ventilation rates (VR), peak inspiratory pressure (PIP) ranges, and test lung compliances. Methods The oxygen concentrations were measured under a variety of conditions. The combinations of oxygen flow rates (10, 5, 3 and 1 L/min), VRs (40, 60 inflations/min), PIP ranges (20 to 25 cm H2O, 35 to 40 cm H2O), and test lung compliances (0.6, 1, 3, and 5 mL/cm H2O) were examined using six kinds of self-inflating bags. Results The delivered oxygen concentrations distributed widely (30.1-96.7%) and had significant positive correlation with the gas flow rate in all of the bags. The concentrations were also negatively correlated with the PIP in all of the bags and with the VR in some of them. The test lung compliance did not affect the delivered oxygen concentration. Conclusion The use of neonatal resuscitation self-inflating bags without reservoirs resulted in different delivered oxygen concentrations depending on the gas flow rate, VR, PIP, and manufacturer, but not on lung compliance. These results suggest that targeted oxygen concentrations could be delivered, even in lungs with decreased compliance, during resuscitation.