Oxygenation Index Calculator

Oxygenation Index Equation:

\[ OI = \frac{FiO_2 \times MAP}{PaO_2} \]

FiO2 (Fraction of Inspired Oxygen):

unitless

MAP (Mean Airway Pressure):

cmH2O

PaO2 (Arterial Oxygen Partial Pressure):

mmHg

Oxygenation Index (OI):

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1. What is the Oxygenation Index?

The Oxygenation Index (OI) is a measure used in critical care medicine to assess the severity of lung disease, particularly in patients requiring mechanical ventilation. It provides an indication of how effectively the lungs are oxygenating the blood relative to the pressure being applied.

2. How Does the Calculator Work?

The calculator uses the Oxygenation Index equation:

\[ OI = \frac{FiO_2 \times MAP}{PaO_2} \]

Where:

\( FiO_2 \) — Fraction of inspired oxygen (unitless)
\( MAP \) — Mean airway pressure (cmH2O)
\( PaO_2 \) — Arterial oxygen partial pressure (mmHg)

Explanation: The equation calculates the ratio of oxygen delivery pressure to arterial oxygen content, providing a measure of oxygenation efficiency.

3. Importance of OI Calculation

Details: OI is crucial for assessing respiratory failure severity, guiding ventilator management, and determining the need for advanced respiratory support such as ECMO. Higher OI values indicate worse oxygenation and more severe lung disease.

4. Using the Calculator

Tips: Enter FiO2 as a decimal (0.21-1.0), MAP in cmH2O, and PaO2 in mmHg. All values must be positive and within physiological ranges.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal Oxygenation Index value?
A: Normal OI is typically less than 5. Values between 5-15 indicate mild to moderate lung injury, 15-25 moderate to severe, and above 25 severe respiratory failure.

Q2: How does OI differ from PaO2/FiO2 ratio?
A: OI incorporates mean airway pressure, making it more comprehensive for patients on mechanical ventilation, while PaO2/FiO2 is simpler but doesn't account for ventilator pressure.

Q3: When is OI most commonly used?
A: OI is primarily used in pediatric and neonatal intensive care, and for assessing acute respiratory distress syndrome (ARDS) in all age groups.

Q4: What are the limitations of OI?
A: OI may be less accurate in patients with significant hemodynamic instability or those receiving high levels of positive end-expiratory pressure (PEEP).

Q5: How often should OI be monitored?
A: In critically ill patients on mechanical ventilation, OI should be monitored regularly (every 4-6 hours) or with significant changes in ventilator settings or clinical condition.