What surrounds the site of intentional expulsion for someone using a nasal cannula?

The area of intentional expulsion for someone using a nasal cannula is effectively surrounded by the mask or cannula itself. The design of the nasal cannula allows for the delivery of medical gases, such as oxygen, directly into the patient's nostrils while simultaneously providing a way for the exhaled air to escape. This means that the cannula is inherently positioned at the point of gas delivery and exhalation, making it the element that contains and directs the expelled air.

Understanding this is crucial in a medical context, as it highlights the specific construction and function of the nasal cannula in managing patient care. Recognizing that the mask or cannula is the immediate area of intentional expulsion helps in understanding issues surrounding airflow and potential contamination in shared spaces, especially in healthcare settings where infection control is paramount. The focus on the mask or cannula emphasizes the importance of ensuring that these devices are correctly fitted and maintained to optimize both patient comfort and the effectiveness of gas delivery.