How does a pulse oximeter function?

A pulse oximeter functions by detecting the amount of oxygen in the bloodstream using light absorption. This device operates on the principle of spectrophotometry, which involves measuring the absorption of specific wavelengths of light as it passes through the blood in peripheral tissues, typically a fingertip or earlobe.

Oxygenated and deoxygenated hemoglobin absorb light differently; thus, the pulse oximeter emits red and infrared light to determine the ratio of oxygenated to deoxygenated hemoglobin in the blood. The device then calculates the oxygen saturation level (SpO2), usual values being between 95% and 100% in healthy individuals. This non-invasive method is crucial during anesthesia and other medical procedures, as it provides real-time monitoring of a patient's oxygenation status, allowing for timely interventions if necessary.

The other options do not describe the function of a pulse oximeter accurately. For instance, measuring heart rate and blood pressure falls under the purview of different monitoring devices (like an electrocardiogram and sphygmomanometer), and monitoring body temperature or analyzing respiratory patterns are also unrelated to the core function of a pulse oximeter, which is specifically focused on assessing oxygen levels in the blood.