What device is typically used to monitor a patient's oxygen saturation levels?

The device used to monitor a patient's oxygen saturation levels is a pulse oximeter. This tool is non-invasive and operates by shining light through a patient's skin, typically on a fingertip or earlobe, to measure the absorption of light by oxygenated and deoxygenated hemoglobin in the blood. By analyzing how much light passes through the tissue, the pulse oximeter can provide a real-time reading of the oxygen saturation level, which is crucial for assessing a patient’s respiratory status and ensuring they receive adequate oxygenation.

The other options focus on different physiological measurements. A sphygmomanometer is used for measuring blood pressure, a stethoscope is utilized for auscultation to listen to internal sounds of the body, such as heartbeats and lung sounds, and a thermometer measures body temperature. While all these devices are important in clinical settings, they do not measure oxygen saturation levels, which specifically requires a pulse oximeter for accurate readings.