What does oxygen percentage delivered by a BVM typically exceed?

The oxygen percentage delivered by a bag-valve-mask (BVM) typically exceeds 40% because the device is designed to deliver a higher concentration of oxygen to a patient who is unable to breathe adequately on their own. When used correctly, a BVM can provide supplemental oxygen during ventilation, especially when it is connected to a source of high-flow oxygen.

In most cases, the concentration of oxygen in ambient air is about 21%, which is not sufficient for patients in respiratory distress; that is why BVMs are utilized in emergency settings to enhance oxygen delivery. The proper technique and seal allow for effective ventilation and the fulfillment of oxygen needs, often yielding a concentration that surpasses 40%. Thus, the correct answer highlights the device's critical role in emergency respiratory support.