A/A Ratio Calculator

Formula

To calculate the A/A Ratio:

\[ \frac{PAO2}{PaO2} \]

Where:

\(A/A\) is the A/A Ratio
\(PAO2\) is the Partial Pressure of Oxygen in Alveoli
\(PaO2\) is the Partial Pressure of Oxygen in Arterial Blood

What is the A/A Ratio?

The A/A Ratio, also known as the Alveolar-arterial Oxygen Gradient, is a measure used in respiratory physiology to assess the efficiency of oxygen transfer from the alveoli to the blood. It is calculated by dividing the partial pressure of oxygen in the alveoli (PAO2) by the partial pressure of oxygen in arterial blood (PaO2). This ratio helps in identifying issues related to gas exchange in the lungs.

Example Calculation 1

Let's assume the following values:

PAO2 = 100
PaO2 = 80

Using the formula:

\[ \frac{100}{80} = 1.25 \]

The A/A Ratio is 1.25.

Example Calculation 2

Let's assume the following values:

PAO2 = 95
PaO2 = 75

Using the formula:

\[ \frac{95}{75} = 1.27 \]

The A/A Ratio is 1.27.