When performing mouth-to-mask ventilations set at 15 L/min, what percentage of oxygen is delivered to the patient?

When performing mouth-to-mask ventilations at a flow rate of 15 liters per minute, approximately 55% of oxygen is delivered to the patient. This specific percentage is important to understand in the context of how oxygen delivery systems work.

When using a mask with a proper seal, some room air is still entrained along with pure oxygen due to the nature of the ventilation process. Therefore, the concentration of oxygen delivered is not as high as it would be with a more direct method of oxygen delivery, such as a non-rebreather mask. The 55% oxygen delivery reflects a combination of the high concentration from the oxygen source and the ambient air that mixes with it. This understanding is crucial when determining the effectiveness of ventilation in emergencies, as providers need to be aware of how much supplemental oxygen is truly reaching the patient.

Understanding the performance characteristics of different ventilation methods also aids in making informed decisions in various scenarios you may encounter as an EMT.