What monitoring equipment is often used to measure oxygen saturation non-invasively?

The pulse oximeter is the instrument used to measure oxygen saturation non-invasively. This device works by using light sensors to assess the changes in light absorption of oxygenated and deoxygenated hemoglobin in the blood, providing a quick and accurate measurement of the percentage of hemoglobin that is saturated with oxygen.

Monitoring oxygen saturation is crucial in various clinical settings, as it helps determine how well oxygen is being transported throughout the body and is essential for managing patients with respiratory or cardiovascular issues. In contrast, other options do not measure oxygen saturation: an electrocardiogram monitors the heart's electrical activity, a stethoscope is used for auscultation to listen to the body’s sounds, and a blood pressure cuff measures arterial blood pressure. Thus, among the available choices, the pulse oximeter is the clear choice for non-invasive measurement of oxygen saturation.