Final answer:
A pulse oximeter is used primarily to determine the oxygen saturation level in the blood, not to measure heart rate, blood pressure, or respiratory rate directly. It functions by projecting light through a body part and measuring light absorption to report a percentage of oxygen saturation.
Step-by-step explanation:
A pulse oximeter is a device used to measure the oxygen saturation (SpO2) level in the blood, which is a critical indicator of oxygen delivery to peripheral tissues. It functions by sending two wavelengths of light through a relatively transparent area of the body, like a fingertip, and measuring the differential absorption of hemoglobin with and without oxygen by using a photodetector. The resulting data is displayed as a percentage, with normal readings typically between 95-100 percent.
Despite also being capable of measuring heart rate, the primary function of a pulse oximeter is indeed to determine oxygen saturation. It does not measure blood pressure or respiratory rate directly, although blood oxygen levels can have an influence on respiratory rate and are detected by peripheral chemoreceptors, which can trigger adjustments in breathing if oxygen levels drop significantly.