PaO₂/FiO₂ Ratio Calculator
P/F ratio and Berlin Definition oxygenation category
Version 1.0.0
PaO₂ units
P/F ratio
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mmHg
P/F ratio
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kPa
Berlin oxygenation category
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For the Berlin definition, mild ARDS (P/F 201–300 mmHg) may meet the oxygenation support criterion with PEEP or CPAP ≥ 5 cm H₂O; moderate and severe ARDS require PEEP ≥ 5 cm H₂O. Diagnosis additionally requires the definition's timing, bilateral chest-imaging opacities and oedema-origin criteria.
No clinical values are intentionally saved by this control.
Equations
PaO₂/FiO₂ ratio in mmHg
P/F (mmHg) = PaO₂ (mmHg) ÷ [FiO₂ (%) ÷ 100]FiO₂ is converted from percentage to a fraction before division. The calculated P/F ratio is rounded to the nearest whole mmHg for display and Berlin oxygenation-category assignment: severe ≤ 100 mmHg, moderate 101–200 mmHg, mild 201–300 mmHg, and > 300 mmHg above the Berlin hypoxaemia range. Mild ARDS may meet the oxygenation support criterion with PEEP or CPAP ≥ 5 cm H₂O; moderate and severe ARDS require PEEP ≥ 5 cm H₂O. Full ARDS diagnosis also requires the Berlin timing, bilateral chest-imaging opacities and oedema-origin criteria.
Pressure conversion
Displayed P/F (kPa) ≈ displayed whole-mmHg P/F ÷ 7.50062The secondary kPa display is an approximate conversion of the displayed whole-mmHg P/F value. Berlin oxygenation-category thresholds are applied to the displayed whole-mmHg value.
References
- ARDS Definition Task Force, Ranieri VM, Rubenfeld GD, Thompson BT, et al. Acute respiratory distress syndrome: the Berlin Definition. JAMA. 2012;307(23):2526-2533. PMID: 22797452 DOI: 10.1001/jama.2012.5669