Partial rebreather mask has FiO2 of what range on a flow rate of 6-10 L/min?

• A. 0.40-0.60+, 6-10 L/min
• B. 0.20-0.40, 4-6 L/min
• C. 0.70-0.90, 12-15 L/min
• D. 0.30-0.50, 2-4 L/min

Answer: (A)

Partial rebreather masks deliver a moderate FiO2 by using a reservoir bag that mixes some of the exhaled gas with fresh oxygen. When the flow is set at 6–10 L/min, the bag stays adequately inflated, and the patient typically inhales an oxygen concentration around 40% to 60% (FiO2 about 0.40–0.60). The exact amount can vary with how deeply and rapidly the person breathes and how well the mask seals, but this mid-range is the usual delivery for that flow. This is lower than what a non-rebreather mask can provide at higher flows, and higher than what a simple mask or nasal cannula typically deliver.