P/F ratio calculation: PaO2 85 mmHg, FiO2 0.40. What is the P/F ratio?

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P/F ratio calculation: PaO2 85 mmHg, FiO2 0.40. What is the P/F ratio?

The P/F ratio shows how well oxygen is moving from the lungs into the blood, calculated as PaO2 divided by FiO2, with FiO2 expressed as a decimal. Here, PaO2 is 85 mmHg and FiO2 is 0.40, so 85 ÷ 0.40 = 212.5. Rounding to the nearest whole number gives 213, making the P/F ratio about 213. This reflects oxygenation efficiency, useful for assessing respiratory status and ARDS severity.

The P/F ratio shows how well oxygen is moving from the lungs into the blood, calculated as PaO2 divided by FiO2, with FiO2 expressed as a decimal. Here, PaO2 is 85 mmHg and FiO2 is 0.40, so 85 ÷ 0.40 = 212.5. Rounding to the nearest whole number gives 213, making the P/F ratio about 213. This reflects oxygenation efficiency, useful for assessing respiratory status and ARDS severity.

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