Aa Gradient

Assess gas exchange efficiency.

Medical Disclaimer

This tool is for educational and screening purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

Gas Exchange Inputs

FiO2 (Decimal, e.g. 0.21)

PaCO2 (mmHg)

PaO2 (mmHg)

Atm Pressure (mmHg)

Alveolar-arterial Gradient

4.7mmHg

Expected: (Age / 4) + 4

An elevated gradient suggests a V/Q mismatch, diffusion defect, or shunt.

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About Aa Gradient

The Alveolar-arterial (A-a) oxygen gradient is a vital diagnostic tool designed to precisely assess the efficiency of pulmonary gas exchange. By quantifying the difference between the partial pressure of oxygen in the alveoli and that in the arterial blood, this gradient provides crucial insights into the functional integrity of the alveolar-capillary membrane. Primarily utilized by pulmonologists, intensivists, and other healthcare professionals, the Aa Gradient is indispensable for differentiating the underlying causes of hypoxemia. Its value lies in its ability to distinguish between hypoventilation and true impairment in oxygen transfer, such as ventilation-perfusion mismatch, shunting, or diffusion defects. This tool empowers clinicians to accurately diagnose various respiratory conditions, thereby guiding targeted treatment strategies and improving patient outcomes.