Non-Rebreather delivers which range of oxygen concentration?

• A. 100%
• B. 24%-44%
• C. 60%-90%
• D. 0%-5%

Answer: (C)

Non-rebreather masks deliver a high concentration of oxygen by using a reservoir bag and one-way valves that limit room air from diluting the inhaled gas. The exact percentage you deliver isn’t fixed; it depends on how well the bag stays inflated and how aggressively the patient breathes. When the bag is fully inflated and the patient inhales with typical effort, the inspired oxygen is in the high range, but it can vary—usually about 60% to 90%. If the bag deflates or the patient breathes very rapidly, the concentration drops toward the lower end. This is why the standard description covers a broad range rather than a single number.