Oxygenation Index Calculator

Form

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Results

PaO₂/FiO₂ ratio

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Oxygenation Index

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What is Oxygenation Index?

Oxygenation index combines inspired oxygen, mean airway pressure and arterial oxygen pressure.

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How to Use This Calculator

  1. Enter or select FiO₂, MAP, PaO₂.
  2. Check the unit beside each measurement. For a percentage or rate, use the scale and time period stated in the form.
  3. Choose Calculate, then compare the output with the formula and example below. If you change a value or option, calculate again to update the result.
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Formula Used

OI = FiO₂ as a fraction × mean airway pressure(cm H₂O) × 100/PaO₂(mmHg).
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Variables Explained

InputWhat it means
FiO₂Use the observed finding or laboratory value for this criterion, following the definition shown in the form.
MAPUse the observed finding or laboratory value for this criterion, following the definition shown in the form.
PaO₂Use the observed finding or laboratory value for this criterion, following the definition shown in the form.
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Worked Example

FiO₂=0.5, mean airway pressure 10 and PaO₂=100 give OI=5.

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Why Use This Calculator?

Use the calculation to make the method and its inputs easier to check with a healthcare professional. Its meaning depends on the clinical setting and on whether the underlying method is appropriate for that person.

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Common Mistakes

    • MAP here means airway pressure, not mean arterial pressure. Distinguish FiO₂ fractions from percentages.
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Frequently Asked Questions

Is this result a diagnosis or treatment instruction?

No. It describes a calculation or score from the supplied information. A qualified clinician must check the measurements, the method’s applicability and the wider clinical picture.

Can I enter the units from any lab report?

Use the units specified in the form and select a conversion only where the page provides one. Different substances need different conversion factors; a mismatch can produce a plausible but incorrect result.

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Sources & References