How is the accumulation of exhaled CO2 prevented in a nasal CPAP mask?

The accumulation of exhaled CO2 is effectively prevented in a nasal CPAP mask through the incorporation of a purposeful leak built into the mask unit. This design allows for exhaled air, which contains CO2, to escape rather than becoming trapped in the mask.

When the patient exhales, the built-in leak facilitates the release of this exhaled air, ensuring that fresh air can be continuously supplied from the CPAP machine. This not only helps maintain effective ventilation but also supports the overall therapeutic benefit of the CPAP therapy by preventing rebreathing of CO2, which can lead to discomfort or hypercapnia.

This mechanism is vital for ensuring patient safety and comfort during CPAP therapy, as it helps to maintain a proper balance of oxygen and carbon dioxide levels while the patient is asleep. The other options, while potentially plausible, do not accurately describe the effective feature of the nasal CPAP mask in managing exhaled gases.