Which oxygen delivery device provides FiO2 approximately 24–44%?

Which oxygen delivery device provides FiO2 approximately 24–44%?

• A. Simple face mask 40–60%
• B. Nasal cannula 24–44%
• C. Partial rebreather mask 60–90%
• D. Venturi mask 24–50%

Answer: (B)

FiO2 with low-flow delivery depends on the device and how much oxygen you push in. A nasal cannula delivers oxygen directly through the nostrils and, as you increase the liter flow, the FiO2 climbs roughly from 24% at about 1 L/min to about 44% at around 6 L/min. That puts its typical FiO2 squarely in the 24–44% range, which is exactly what this question is asking for. Other devices push FiO2 higher. A simple face mask generally provides about 40–60% FiO2, which starts above the lower end of the range. A partial rebreather mask delivers even higher FiO2, around 60–90%. A Venturi mask can deliver a precise FiO2 across a wide range, commonly described as 24–50% or similar, but its purpose is to tailor FiO2 to a specific value, and the range isn’t as tightly tied to the 24–44% window as the nasal cannula is.

FiO2 with low-flow delivery depends on the device and how much oxygen you push in. A nasal cannula delivers oxygen directly through the nostrils and, as you increase the liter flow, the FiO2 climbs roughly from 24% at about 1 L/min to about 44% at around 6 L/min. That puts its typical FiO2 squarely in the 24–44% range, which is exactly what this question is asking for.

Other devices push FiO2 higher. A simple face mask generally provides about 40–60% FiO2, which starts above the lower end of the range. A partial rebreather mask delivers even higher FiO2, around 60–90%. A Venturi mask can deliver a precise FiO2 across a wide range, commonly described as 24–50% or similar, but its purpose is to tailor FiO2 to a specific value, and the range isn’t as tightly tied to the 24–44% window as the nasal cannula is.