What does a pulse oximeter measure?

A pulse oximeter is a non-invasive device used primarily to measure the percentage of oxygen saturation in a patient's blood. It works by passing light through a relatively thin part of the body, typically a fingertip or an earlobe, and measuring the amount of red and infrared light that is absorbed by the blood. This absorption correlates with the amount of oxygen bound to hemoglobin in the red blood cells, allowing the device to determine the oxygen saturation level.

The primary function of a pulse oximeter is to provide a quick and reliable assessment of how effectively oxygen is being transported in the bloodstream, which is crucial for evaluating a patient's respiratory and overall physiological status. By indicating the percentage of hemoglobin that is saturated with oxygen, clinicians can assess whether a patient is receiving adequate oxygenation, which is vital for diagnosing and managing various medical conditions.

Understanding this concept is essential for emergency medical technicians and healthcare providers, as monitoring oxygen saturation helps guide treatment decisions and can indicate the need for supplemental oxygen or other interventions in acute respiratory events.