When performing mouth-to-mask ventilations with oxygen connected at a rate of 15 L/min, what percentage of oxygen is your patient receiving?

• A. 45%
• B. 50%
• C. 55%
• D. 60%

Answer: (C)

When performing mouth-to-mask ventilations with supplemental oxygen at a flow rate of 15 liters per minute, the patient typically receives a higher concentration of oxygen compared to normal room air due to the oxygen source directly supplying oxygen through the mask.

At a flow rate of 15 L/min, the oxygen concentration delivered can be estimated to be around 55%. This is based on the understanding that as the flow rate of oxygen increases, the percentage of oxygen that the patient receives also increases. The mask creates a seal, which allows for a higher intake of oxygen during the positive pressure ventilation that you provide.

When considering the flow rate of 15 L/min and typical respiratory physiology, it aligns with the figure of approximately 55% oxygen delivery. Lower oxygen flow rates would yield lower percentages, whereas significantly higher flow rates can increase the percentage further. However, at 15 L/min, the effective oxygen concentration is recognized as being around 55%, making it the best choice among the options presented.