An instrument used to monitor the oxygen saturation of sedated patients is called a/an?

A pulse oximeter is the correct choice because it measures the oxygen saturation level in a patient's blood. This non-invasive instrument is especially important for sedated patients, as their respiratory function may be compromised, and monitoring their oxygen levels can help ensure that they are receiving adequate oxygen during sedation. The pulse oximeter works by using light sensors placed on the skin (commonly on a fingertip) to estimate the amount of oxygenated versus deoxygenated hemoglobin in the blood, providing real-time feedback on the patient's respiratory status.

The other instruments listed serve different purposes. A blood pressure cuff is used to measure blood pressure, which is not directly related to monitoring oxygen saturation. An electrocardiogram (ECG or EKG) records the electrical activity of the heart and is used to assess cardiac function, not oxygen levels. A thermometer is utilized to measure body temperature, which again does not provide information about oxygen saturation. Each of these tools plays a crucial role in patient monitoring, but only the pulse oximeter is specifically designed for assessing oxygen saturation levels.