Medical calculators

P/F Ratio

PaO₂/FiO₂ Ratio

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How it is calculated

P/F Ratio = PaO₂/FiO₂. Normal >400. These are ARDS severity bands, not a diagnosis: ARDS (Berlin) also needs PEEP or CPAP of at least 5, bilateral opacities, onset within a week, and oedema not explained by cardiac failure.

About

PaO2 divided by FiO2, the standard measure of oxygenation impairment and part of the ARDS definition.

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