Checking the respiratory rate and listening to the lungs do not always give health care providers a clear picture of how the lungs are functioning, so the pulse oximeter was invented.

A pulse oximeter is a small device that painlessly clips onto a person’s fingertip or earlobe. A special light is beamed from one side of the probe to the other, and measures the heart rate and the amount of oxygen in the blood. A normal oxygen saturation reading is 95 percent or above.