That means the machine has an airtight mask and could in principle suffocate you if it malfunctions. One of the most popular masks is the ResMed Airfit P10.[1

That means the machine has an airtight mask and could in principle suffocate you if it malfunctions. One of the most popular masks is the ResMed Airfit P10.[1] This is a "nasal pillows mask". It is airtight, but only on your nose. If the mask malfunctions or your nose clogs up, then instead of suffocating, you can open your mouth to breathe. A full-face mask can presumably malfunction, even though it has a "failsafe" feature to let you breathe. [1] https://www.resmed.com/us/en/consumer/products/masks/airfit-p10.html https://www.resmed.com/us/en/consumer/products/masks/airfit-...