What OI thresholds indicate ECMO candidacy?

An OI ≥40 for ≥3 hours, or OI ≥30 for ≥6 hours, is commonly used as a threshold for considering venovenous ECMO referral in adults with refractory ARDS. In neonates, OI ≥40 is the primary criterion for ECMO initiation. The OI incorporates mean airway pressure, making it more comprehensive than P/F ratio for assessing ventilator-dependent oxygenation.

How does Oxygenation Index differ from P/F ratio?

The P/F ratio (PaO2/FiO2) only accounts for the inspired oxygen fraction. The Oxygenation Index additionally incorporates mean airway pressure (MAP), reflecting the total ventilatory support required to achieve oxygenation. Higher MAP for the same P/F ratio indicates more severe underlying lung disease; thus OI better captures overall respiratory failure severity in mechanically ventilated patients.

Oxygenation Index Calculator

Calculate the Oxygenation Index (OI = FiO2 × Mean Airway Pressure × 100 / PaO2) to assess respiratory failure severity and guide ECMO or inhaled nitric oxide candidacy.

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Frequently Asked Questions

What OI thresholds indicate ECMO candidacy?

How does Oxygenation Index differ from P/F ratio?