What does a pulse oximeter primarily measure?

A pulse oximeter primarily measures the level of oxygenated hemoglobin compared to total hemoglobin in the blood. This measurement is crucial for assessing a patient's respiratory function and overall oxygenation status. The device utilizes light absorption properties of hemoglobin; as oxygenated hemoglobin absorbs light differently than deoxygenated hemoglobin, the pulse oximeter can calculate the oxygen saturation (SpO2) by analyzing the wavelengths of light that pass through a peripheral site, such as a finger or earlobe.

This measurement is vital in many medical contexts, especially during surgical procedures and in monitoring patients with respiratory issues. By providing a non-invasive and real-time assessment of blood oxygen levels, it enables timely interventions if a patient's oxygen saturation levels fall below acceptable ranges, thus ensuring patient safety and supporting effective management of their care. Other measurement parameters, such as heart rate, blood pressure, or body temperature, are not the primary focus of a pulse oximeter's function, as these are assessed using different instruments and methods.