PAO2 (Alveolar Oxygen)

The alveolar gas equation calculates the partial pressure of oxygen in the alveoli (PAO2). This is essential for computing the A-a gradient and assessing oxygenation status.

Disclaimer

This calculator is for educational purposes only. Always verify with clinical judgment.

Calculator

FiO2 (fraction, e.g. 0.21)

PaCO2 (mmHg)

Atmospheric Pressure (mmHg)

Water Vapor Pressure (mmHg)

Respiratory Quotient (RQ)

Formula

PAO2 = FiO2 × (Patm - PH2O) - (PaCO2 / RQ)

References

West JB. Respiratory Physiology: The Essentials, 10th Edition.
Hess DR, Kacmarek RM. Essentials of Mechanical Ventilation, 4th Edition.