What is the primary function of a simple mask in oxygen therapy?

The primary function of a simple mask in oxygen therapy is to cover both the nose and mouth for effective delivery of oxygen. This design is essential because it allows for a reliable and consistent flow of therapeutic oxygen into the patient's airway, enhancing the oxygen concentration that reaches the lungs. By encompassing both the nose and mouth, the mask ensures that oxygen can be inhaled effectively regardless of the patient's breathing habits, making it suitable for various situations, including those with shallow or irregular breathing patterns.

While other options touch on aspects related to oxygen delivery or patient behavior, they do not encapsulate the main purpose of the simple mask. It does not specifically prevent the mixing of exhaled air with the oxygen supply as in more advanced masks, nor is its main intent to deliver low concentrations of oxygen; in fact, a simple mask can provide moderate concentrations of oxygen. Encouraging slow breathing is also not a primary feature associated with its use; rather, the focus is on facilitating adequate oxygen therapy through a straightforward method.