Final answer:
During anesthesia, the amount of oxygen in the blood is measured using a pulse oximeter, which provides oxygen saturation levels, or through an arterial blood gas test measuring partial pressure of oxygen.
Step-by-step explanation:
During anesthesia, the monitoring of oxygenation involves measuring the amount of oxygen in the blood. This is critically important to ensure that the patient is receiving sufficient oxygen while under anesthesia. To measure oxygen levels, medical professionals use a pulse oximeter, a device that estimates the percentage of oxygen saturation in hemoglobin. The pulse oximeter operates by sending red and infrared light through a thin part of the body, such as a fingertip, to measure the differential absorption of light by oxygenated and partially oxygenated hemoglobin. Normal readings typically range from 95-100 percent. Values below this range are indicative of hypoxemia, signifying low blood oxygen. Alternatively, blood oxygen can also be measured through an arterial blood gas test, which measures the partial pressure of oxygen (pO₂) in the blood, usually in millimeters of mercury (mm Hg). The peripheral chemoreceptors, which sense oxygen dissolved in the blood, can trigger an increase in respiratory rate if these levels fall significantly.