Oxygen Index (OI)

Oxygen Index

Oxygenation Index = (FiO2 * Mean Airway Pressure) / PaO2
The oxygenation index is used to assess the intensity of ventilatory support required to maintain oxygenation. It is used in neonates / pediatrics to assess the need for potential ECMO therapy.

Fraction of inspired oxygen (FiO2) in %:
Mean airway pressure (MAP) in mmHg:
Partial pressure of oxygen (PaO2) in mmHg:
Oxygenation Index (OI)

0-25 index : Good outcome
25-40 index : Chance of death > 40%
30-1000 index : > 4 hours – Increased risk of worsening / death
40-1000 index : Consider ECMO (extracorporeal membrance oxygenation)

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M Van Haperen . “The Oxygenation Index compared with the P/F ratio in ALI/ARDS”. Critical Care.
http://ccforum.com/content/16/S1/P91 (30 May, 2012)

Brudno DS, Boedy RF, Kanto WP Jr. Compliance, alveolar-arterial oxygen difference, and oxygenation index changes in patients managed with extracorporeal membrane oxygenation. Pediatric Pulmonology 1990; 9(1): 19–23 . PubMed PMID: 2388774.


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