Which device is usually the preferred method of oxygen administration in prehospital care and is considered high-flow, delivering up to 90% O2 at 10-15 L/min?

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

Answer: (A)

High-flow oxygen delivery with a nonrebreather mask is the standard choice for spontaneously breathing patients who need a high concentration of oxygen. When connected to a 10–15 L/min source and sealed properly, the mask fills its reservoir and delivers up to about 90% oxygen. The one-way valves prevent room air from diluting the mix, and exhaled air exits through the mask’s ports, keeping the inhaled FiO2 high.

Nasal cannulas provide lower oxygen concentrations, typically up to about 44% at higher flow rates, and are less effective for patients requiring substantial oxygen. Simple face masks can deliver more than a nasal cannula but usually max out around 40–60% FiO2 and depend on flow rate and fit. Bag-valve masks can deliver near-pure oxygen, but they are designed for ventilating patients who aren’t breathing adequately or at all, requiring manual compression, so they’re not the usual method for a patient who is breathing adequately on scene.