What does a nasal cannula primarily deliver in terms of oxygen concentration?

A nasal cannula primarily delivers a variable concentration of oxygen. This method of oxygen delivery allows for a range of oxygen concentrations, typically between 24% to 40%, depending on the flow rate of oxygen being provided and the patient's breathing patterns. Because the nasal cannula vents to room air, the actual amount of oxygen that the patient receives can fluctuate with their inhalation and exhalation, which effectively makes it a variable delivery system.

It's also important to consider that while some might think of it as providing low concentrations, the effectiveness can increase with higher flow rates, but it cannot accurately provide a fixed high concentration like more specialized equipment, such as a non-rebreather mask, would. This characteristic of the nasal cannula aligns it more closely with variable concentrations rather than a consistently low or high concentration, making it particularly versatile for patients who require supplemental oxygen without the need for higher flow systems.