Supplemental Oxygen And Oxygen Management Practice Test

Nasal cannulas are designed for low-to-moderate oxygen needs, delivering gas in a flow range that patients can tolerate comfortably. The typical flow range is 1–6 L/min because within this window you get reliable, steady oxygen delivery without causing too much drying or discomfort. Below 1 L/min the delivered FiO2 can be inconsistent and insufficient for many patients. Pushing flow beyond about 6 L/min with a simple nasal cannula doesn’t significantly raise FiO2 and can increase nasal irritation; for higher oxygen needs, clinicians switch to other devices that provide higher and more controlled FiO2, such as masks or high-flow systems. Actual FiO2 also depends on breathing pattern and whether the patient breathes through the nose or mouth, with mouth breathing tending to lower the effective FiO2 from the stated flow.