A pulse oximeter is a device that checks how much oxygen is in the blood.
A small
clip is put on a finger, toe, or earlobe. The light beam in the clip measures
the oxygen of the red blood cells that move through the cells in the finger,
toe, or earlobe. The person's oxygen level can be read on the display.
The pulse oximeter often has an alarm for blood oxygen levels that
fall below a safe level.