Which device is used to measure the oxygen saturation in the blood?

The pulse oximeter is the correct tool for measuring the oxygen saturation in the blood. This non-invasive device clips onto a patient's fingertip or earlobe and utilizes light-emitting diodes to measure the percentage of hemoglobin molecules in the blood that are saturated with oxygen. The readings provided by a pulse oximeter are vital for assessing a patient's respiratory status, especially in emergency situations, where understanding hypoxia can guide intervention strategies.

The other devices have distinct purposes: a stethoscope is primarily used for auscultation to listen to heart and lung sounds, enabling clinicians to evaluate cardiac and respiratory function. A sphygmomanometer measures blood pressure, which is an important but separate physiological parameter. Lastly, a capnometer measures the concentration of carbon dioxide in exhaled air, providing insights into a person's ventilation status but not directly measuring oxygen saturation. Understanding the specific functions of these devices is essential for effective patient assessment and care in emergency medical settings.