What is Oxygen Saturation?

Oxygen saturation (SO₂) is a vital clinical parameter that measures the percentage of hemoglobin binding sites in the bloodstream occupied by oxygen. In healthy individuals, arterial oxygen saturation (SaO₂) typically ranges between 95% and 100%. This measurement is crucial because it indicates how effectively your respiratory system is delivering oxygen to the blood, which is then transported to the heart, brain, and other vital organs.

How This Calculator Works

This calculator utilizes the Severinghaus equation, a widely accepted mathematical model that describes the oxyhemoglobin dissociation curve. The relationship between the partial pressure of oxygen (PaO₂) and the actual saturation percentage is not linear; it is sigmoidal (S-shaped). This means that at very high pressures, saturation plateaus, while at lower pressures, small changes in PaO₂ lead to significant drops in oxygen saturation.

How to Use the Calculator

Using this tool is straightforward. Simply obtain your Partial Pressure of Oxygen (PaO₂) value, usually provided by an Arterial Blood Gas (ABG) test. Enter the numerical value in mmHg into the input field above and click "Calculate Saturation." The tool will immediately provide an estimated percentage of your oxygen saturation levels.

Frequently Asked Questions

What is a normal PaO2 level? A normal PaO₂ for a healthy adult at sea level is typically between 75 and 100 mmHg.

What is Hypoxemia? Hypoxemia occurs when the oxygen levels in the blood are lower than normal. This is usually defined as a PaO₂ lower than 60 mmHg or a saturation level below 90%.

Can I use this instead of a Pulse Oximeter? This calculator estimates saturation based on partial pressure. While pulse oximeters measure SpO₂ directly through the skin, this tool is helpful for clinicians or students interpreting lab results like ABGs.