Which oxygen delivery system provides 12–15 L/min and 85–100% O2 with a tight-seal mask?

Which oxygen delivery system provides 12–15 L/min and 85–100% O2 with a tight-seal mask?

• A. Partial Re-Breather
• B. Non Re-Breather
• C. Bag Valve Mask - O2 Powered
• D. Simple Face Mask

Answer: (B)

Delivering a high concentration of oxygen to a patient who is breathing on their own requires a mask that seals well and supplies a high flow. The non-rebreather mask is designed for this. It uses a tight-fitting mask plus a reservoir bag and one-way valves that prevent exhaled gas or room air from entering the bag. When oxygen is delivered at about 12–15 L/min, the bag remains inflated during inspiration, so the air the patient inhales is largely from the oxygen reservoir. This setup yields an inspired oxygen concentration near 85–100% when the seal is good, making it the best choice for achieving the highest FiO2 in spontaneously breathing patients. In contrast, a partial rebreather mask also has a reservoir but lacks complete one-way valve protection, so some exhaled gas can mix back in, leading to lower FiO2 (often significantly less than the non-rebreather). A simple face mask covers the nose and mouth but without a reservoir or valves, so it delivers a much lower FiO2 (generally well below 85% even at higher flows). A bag-valve-mask setup can deliver near 100% O2, but it’s intended for manual ventilation and requires active squeezing of the bag, not a fixed high-flow delivery for a patient who is simply breathing spontaneously.

Delivering a high concentration of oxygen to a patient who is breathing on their own requires a mask that seals well and supplies a high flow. The non-rebreather mask is designed for this. It uses a tight-fitting mask plus a reservoir bag and one-way valves that prevent exhaled gas or room air from entering the bag. When oxygen is delivered at about 12–15 L/min, the bag remains inflated during inspiration, so the air the patient inhales is largely from the oxygen reservoir. This setup yields an inspired oxygen concentration near 85–100% when the seal is good, making it the best choice for achieving the highest FiO2 in spontaneously breathing patients.

In contrast, a partial rebreather mask also has a reservoir but lacks complete one-way valve protection, so some exhaled gas can mix back in, leading to lower FiO2 (often significantly less than the non-rebreather). A simple face mask covers the nose and mouth but without a reservoir or valves, so it delivers a much lower FiO2 (generally well below 85% even at higher flows). A bag-valve-mask setup can deliver near 100% O2, but it’s intended for manual ventilation and requires active squeezing of the bag, not a fixed high-flow delivery for a patient who is simply breathing spontaneously.