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Oxygenation Index Calculator

Work out oxygenation index instantly with clear inputs, formula shown and shareable results.

About Oxygenation Index Calculator

Combines mean airway pressure with inspired oxygen and arterial oxygen tension, the index used in paediatric acute lung injury grading.

Formula

Oxygenation index

OI = FiO2 (%) x mean airway pressure (cmH2O) / PaO2 (mmHg)

Worked example

With the default values below, Oxygenation Index Calculator returns Oxygenation index of 12.86. Change any input above and every figure here is recalculated in your browser.

Inputs used

Inspired oxygen fractionaccepts 21–100 %
60 %
Mean airway pressureaccepts 3–40 cmH2O
15 cmH2O
PaO2accepts 20–400 mmHg
70 mmHg

Results

Oxygenation index
12.86
Severity band
Moderate
PaO2/FiO2 ratio for comparison
117

Step by step

  1. 1Values used
  2. 2Oxygenation index
  3. 3Oxygenation index= 12.86
  4. 4Severity band= Moderate
  5. 5PaO2/FiO2 ratio for comparison= 117

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
  • This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

Why include airway pressure?

It reflects the ventilator support required to achieve the oxygen level, which a P/F ratio alone ignores.

What bands are used?

PALICC grades paediatric ARDS as mild 4-8, moderate 8-16 and severe 16 or above.

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