PaO2/FiO2 Ratio Calculator

Formula

To calculate the PaO2/FiO2 Ratio (P/F Ratio):

\[ \text{P/F Ratio} = \frac{\text{PaO2}}{\text{FiO2}} \]

Where:

\(\text{P/F Ratio}\) is the PaO2/FiO2 Ratio
PaO2 is the partial pressure of oxygen in arterial blood (mmHg)
FiO2 is the fraction of inspired oxygen (expressed as a decimal)

What is the PaO2/FiO2 Ratio?

The PaO2/FiO2 Ratio (P/F Ratio) measures the efficiency of oxygen transfer in the lungs. It is commonly used to assess the severity of acute respiratory distress syndrome (ARDS) and other conditions affecting lung function[^1^][^2^].

Example Calculation 1

Let's assume the following values:

PaO2 = 90 mmHg
FiO2 = 40%

Using the formula:

\[ \text{P/F Ratio} = \frac{90}{0.40} = 225 \]

The PaO2/FiO2 Ratio is 225.

Example Calculation 2

Let's assume the following values:

PaO2 = 80 mmHg
FiO2 = 50%

Using the formula:

\[ \text{P/F Ratio} = \frac{80}{0.50} = 160 \]

The PaO2/FiO2 Ratio is 160.