A pulse oximeter is a medical device that is used to measure the percentage of oxygen in the blood. The device is typically worn on the fingertip of a user's non-dominant hand. The sensor is typically a light-emitting diode (LED) that shines through the finger's nail and into the capillaries, where it measures the amount of hemoglobin in the blood. The sensor emits light and then measures how long it takes for the light to be absorbed by the blood, which is then converted into a measurement of the oxygen saturation. Pulse oximeters are often used in hospitals to monitor the oxygen levels of patients in a variety of settings, including intensive care units and emergency rooms.
