What is the primary purpose of a nasal cannula?

The primary purpose of a nasal cannula is to supply a low flow of oxygen, making it an effective and commonly used device for patients needing supplemental oxygen in a comfortable and non-invasive manner. It consists of a lightweight tube that splits into two prongs, which fit into the nostrils, allowing for continuous delivery of oxygen directly to the patient's nasal mucosa.

This method is particularly beneficial for patients with mild to moderate respiratory distress or chronic respiratory conditions, as it enables them to receive a steady supply of oxygen while still being able to talk, eat, and move more freely compared to other forms of oxygen delivery like face masks.

In contrast, high flow oxygen delivery methods provide significantly higher concentrations of oxygen, which is beyond the capability of a standard nasal cannula. Similarly, devices intended for delivering medication directly to the lungs, such as nebulizers or metered-dose inhalers, serve a different purpose altogether. Monitoring blood oxygen levels is also not a function of the nasal cannula; instead, it is done using pulse oximeters or arterial blood gas analysis. Thus, the correct answer accurately reflects the fundamental role of a nasal cannula in oxygen therapy.