What does pulse oximetry measure?

Pulse oximetry primarily measures the percentage of bound hemoglobin, specifically how much hemoglobin in the blood is saturated with oxygen. This is critical for assessing oxygenation status in patients, as it helps determine how effectively oxygen is being transported to tissues throughout the body.

The device works by using light absorption characteristics of oxygenated and deoxygenated hemoglobin, providing a non-invasive way to monitor a patient's oxygen saturation in real-time. This measurement is essential for identifying hypoxemia, or low levels of oxygen in the blood, which can lead to tissue damage and other serious complications if not addressed promptly.

In contrast, other measurements mentioned, such as heart rate and rhythm or respiratory rate and effort, while important for overall patient assessment, are not captured by pulse oximetry. Additionally, pulse oximetry does not directly measure carbon dioxide levels; that function requires different monitoring tools, such as a capnometer.