When bag-mask ventilating with oxygen connected at 15 L/min, what percentage of oxygen are you delivering?

When bag-mask ventilating with oxygen connected at 15 L/min, what percentage of oxygen are you delivering?

• A. 55%
• B. 45%
• C. 65%
• D. Nearly 100%

Answer: (D)

When you use a bag-valve mask with a reservoir and a high oxygen flow (15 L/min), the reservoir becomes filled with oxygen. During inspiration, the patient mostly breathes from that reservoir, and the device’s one-way valves prevent much room air from sneaking in. Because the oxygen flow is high and the seal is good, the inspired gas is almost all oxygen, approaching 100% FiO2. If the seal were poor or the flow insufficient, you’d entrain more room air and the delivered oxygen percentage would drop. So, delivering nearly pure oxygen is the typical outcome in this setup.

When you use a bag-valve mask with a reservoir and a high oxygen flow (15 L/min), the reservoir becomes filled with oxygen. During inspiration, the patient mostly breathes from that reservoir, and the device’s one-way valves prevent much room air from sneaking in. Because the oxygen flow is high and the seal is good, the inspired gas is almost all oxygen, approaching 100% FiO2. If the seal were poor or the flow insufficient, you’d entrain more room air and the delivered oxygen percentage would drop. So, delivering nearly pure oxygen is the typical outcome in this setup.