What does a pulse oximeter primarily measure?

A pulse oximeter primarily measures the oxygen saturation level of a patient's blood. It does this by using light absorption principles to determine the proportion of hemoglobin that is saturated with oxygen in the arterial blood.

When a pulse oximeter is placed on a thin part of the body, such as a fingertip or earlobe, it emits light wavelengths through the tissue and measures the light that is transmitted. It calculates the ratio of oxyhemoglobin to deoxyhemoglobin, which allows it to provide a percentage that indicates how much oxygen is being carried by the hemoglobin in the blood.

This measurement is critical in monitoring patients, particularly during procedures requiring anesthesia, as it helps ensure that they are receiving adequate oxygenation. A normal oxygen saturation level typically ranges from 95% to 100%, and deviations from this range can indicate hypoxemia or other respiratory concerns.

Other measurements, such as heart rate, blood pressure, and carbon dioxide levels, are important for overall patient assessment but are not the primary function of a pulse oximeter. Heart rate may be observed through other means, blood pressure is measured using a sphygmomanometer or similar devices, and carbon dioxide levels are generally assessed via capnography or arterial