Influence of tidal volume, respiratory rate, and supplemental oxygen flow on delivered oxygen fraction using a mouth to mask ventilation device

Abstract

We examined the influence of the following parameters in determining the FiO 2 delivered to a pediatric lung model using the mouth-to-mask method of resuscitation: rate of ventilation, inspiratory tidal volumes, and supplemental oxygen flow. With a ventilator rate of 20/min and tidal volumes ( V t) ⩽ 100 mL, an FiO 2 of approximately .50 was observed with a supplemental oxygen flow of 5 L/min. Increasing the supplemental oxygen flow to 15 L/m did not appreciably increase the FiO 2 (FiO 2 = .53 versus FiO 2 = .60, respectively), but did cause a significant and unintended increase in V t. Similar results were noted with a ventilator rate of 12/min and VI ⩽ 100 mL (FiO 2 = .68 versus FiO 2 = .73, respectively). We also observed a potentially hazardous situation involving the positioning of the supplemental oxygen port that might result in high inspiratory pressures (stacking of breaths) to the pediatric patient. We believe additional testing is warranted prior to widespread use of this device in children.