What primary method is used to assist with Don Johnson's breathing?

In this scenario regarding Don Johnson's breathing assistance, the use of a simple face mask is significant because it effectively delivers oxygen to the patient, especially in situations where a higher concentration of oxygen is not critical. The simple face mask covers the mouth and nose and can provide supplemental oxygen, making it suitable for patients who do not require intensive respiratory support.

This method allows for a moderate increase in oxygen levels via the gas exchange that occurs when air from the surrounding environment is mixed with the oxygen provided through the mask. It's especially useful for patients who are alert and able to breathe comfortably but may have conditions that necessitate additional oxygen support.

In contrast, other options such as an endotracheal tube are more invasive and are used in cases where a patient cannot breathe on their own or needs respiratory protection. Non-rebreather masks provide a higher concentration of oxygen and are typically reserved for emergencies or more severely compromised patients. Nasal cannulas are less suitable for patients requiring a larger volume of oxygen and would not be the best choice in every situation. The choice of the simple face mask indicates a moderate approach where the patient is still able to breathe independently, but with enhanced oxygenation.