How does a Pulse Oximeter work

The measurements are obtained by simply shining two wavelengths of light (1 is a visible red beam, the other an invisible infrared beam) at the fingertip. By measuring how much light has been absorbed by the oxygen in the blood, an oxygen saturation or “sats” reading is established and displayed as a percentage of the maximum amount of oxygen the blood could carry.

The oximeter looks for minute changes in absorption as the blood is pumped past the measurement site by the beating of the heart, so selecting somewhere with strong pulse is important. A weak pulse or restricted blood flow may limit the oximeter’s ability to obtain accurate measurements.

In the same way, introducing false pulses of blood, such as extreme movement of the measurement site, could equally affect the oximeter’s performance. It is important to understand what the oximeter is doing to ensure you get the best out of your oximeter.