What is the primary function of a Venturi mask?

• A. To humidify inspired air.
• B. To provide precise, fixed FiO₂ settings.
• C. To deliver variable oxygen concentrations.
• D. To remove carbon dioxide.

Answer: (B)

Venturi masks are designed to deliver a specific, fixed oxygen concentration by using calibrated adapters that entrain a precise amount of room air. This setup creates a stable FiO2 that does not vary much with how deeply or rapidly a patient breathes, which is crucial for patients who require exact oxygen levels, such as those with COPD where too much oxygen can be harmful. Humidification isn’t the primary purpose of this device, though it can be added if needed. The mask does not provide a variable oxygen concentration, and it doesn’t remove carbon dioxide; those functions are related to ventilation and gas exchange, not the delivery device’s main role.