How does pulse oximetry work?

Pulse oximetry is a non-invasive medical test that measures the oxygen saturation of a patient's blood. It works by shining a light through a patient's finger or earlobe and measuring the amount of light that is absorbed by the blood. The amount of light that is absorbed depends on the amount of oxygen in the blood, and by measuring the amount of absorbed light, the oxygen saturation can be calculated.

The basic principle behind pulse oximetry is that oxygenated blood absorbs more red light than infrared light, while deoxygenated blood absorbs more infrared light than red light. A pulse oximeter uses two light sources, one red and one infrared, which are shone through a patient's finger or earlobe. The light that passes through the tissue is then detected by a photodiode, which converts the light into an electrical signal. This electrical signal is then processed by a microprocessor, which calculates the oxygen saturation and displays it on a screen.

Pulse oximetry is a very simple and painless procedure that can be used to quickly and easily measure a patient's oxygen saturation. It is often used in hospitals, clinics, and other medical settings, and can also be used at home by patients who have certain medical conditions.