Which oxygen delivery system uses an oxygen reservoir bag to provide higher FiO2?

Which oxygen delivery system uses an oxygen reservoir bag to provide higher FiO2?

• A. Reservoir masks
• B. Simple face mask
• C. Venturi mask
• D. Nasal cannula

Answer: (A)

The ability to deliver a higher inspired oxygen concentration comes from having an oxygen reservoir that the patient can draw from each breath. A reservoir mask (the non-rebreather type) includes a bag that fills with oxygen. During inhalation, the patient pulls from that bag, while exhaled air exits through one-way valves, preventing it from entering the bag. This setup minimizes dilution with room air and allows FiO2 to approach the oxygen supply, giving a higher fraction of inspired oxygen than other common masks when the flow is set correctly. In contrast, a simple face mask has no reservoir—its FiO2 depends on how well the mask fits and the flow rate, generally providing a moderate, variable concentration. A Venturi mask delivers a precise, fixed FiO2 by mixing oxygen with room air but still lacks a reservoir, so it isn’t designed for the highest possible FiO2. A nasal cannula delivers oxygen through prongs with no reservoir, and while increasing flow raises FiO2, it cannot achieve the high concentrations provided by a reservoir mask.

The ability to deliver a higher inspired oxygen concentration comes from having an oxygen reservoir that the patient can draw from each breath. A reservoir mask (the non-rebreather type) includes a bag that fills with oxygen. During inhalation, the patient pulls from that bag, while exhaled air exits through one-way valves, preventing it from entering the bag. This setup minimizes dilution with room air and allows FiO2 to approach the oxygen supply, giving a higher fraction of inspired oxygen than other common masks when the flow is set correctly.

In contrast, a simple face mask has no reservoir—its FiO2 depends on how well the mask fits and the flow rate, generally providing a moderate, variable concentration. A Venturi mask delivers a precise, fixed FiO2 by mixing oxygen with room air but still lacks a reservoir, so it isn’t designed for the highest possible FiO2. A nasal cannula delivers oxygen through prongs with no reservoir, and while increasing flow raises FiO2, it cannot achieve the high concentrations provided by a reservoir mask.