What is the estimated FiO2 delivered by a nasal cannula at 2 L/min?

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Multiple Choice

What is the estimated FiO2 delivered by a nasal cannula at 2 L/min?

Estimating FiO2 from a nasal cannula uses a simple rule: start with room air FiO2 of about 0.21 (21%), and add roughly 0.04 (4 percentage points) for each liter per minute of flow. At 2 L/min, that’s 0.21 + (2 × 0.04) = 0.29. So the estimated FiO2 is about 0.29 (29%). Keep in mind this is an approximation—the actual FiO2 can vary with how deeply you breathe, mouth versus nose breathing, and how well the cannula fits. But 0.29 is the standard estimate for 2 L/min.

Estimating FiO2 from a nasal cannula uses a simple rule: start with room air FiO2 of about 0.21 (21%), and add roughly 0.04 (4 percentage points) for each liter per minute of flow. At 2 L/min, that’s 0.21 + (2 × 0.04) = 0.29. So the estimated FiO2 is about 0.29 (29%).

Keep in mind this is an approximation—the actual FiO2 can vary with how deeply you breathe, mouth versus nose breathing, and how well the cannula fits. But 0.29 is the standard estimate for 2 L/min.

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