Which device delivers high-flow oxygen (10-15 L/min)?

• A. Nasal Cannula
• B. Simple Mask
• C. Nonrebreather Mask
• D. Bag-Valve Mask

Answer: (C)

Nonrebreather masks are designed to deliver a high concentration of oxygen at high flow, typically around ten to fifteen liters per minute. The mask includes a reservoir bag and one-way valves that prevent room air or exhaled air from diluting the gas being breathed in. When flow is enough to keep the reservoir inflated, the inhaled gas remains rich in oxygen, yielding a high FiO2 suitable for rapidly improving oxygenation in emergencies. In contrast, a nasal cannula provides only low flow (usually up to about six liters per minute) with lower and more variable oxygen concentration; a simple mask offers moderate flow but doesn’t consistently maintain a high FiO2 or a full reservoir; a bag-valve mask can deliver very high flow and ventilation but is used for assisted breaths rather than continuous oxygen delivery to a spontaneously breathing patient.