What is a CON of high flow nasal cannula?

• A. More effective for mouth breathers
• B. Causes nasal trauma
• C. Requires more energy
• D. Less effective for mouth breathers

Answer: (D)

High flow nasal cannula delivers heated, humidified oxygen primarily through the nasal passages and creates a gentle positive pressure while washing out stale air from the upper airway. Its effectiveness relies on the patient breathing through the nose. When a person breathes predominantly through the mouth, much of the high-flow gas can escape through the oral cavity instead of reaching the lower lungs, reducing the delivered FiO2 and the airway pressure that HFNC provides. That means the therapy is less effective for mouth breathers, which is why this is considered a drawback.

In contrast, concerns like nasal trauma are possible but not the main limitation of HFNC, and the idea that it would be more effective for mouth breathers isn’t supported by how the device delivers gas. The notion that it requires more energy isn’t a primary clinical drawback compared to the impact of mouth breathing on delivery.