A pulse oximeter is a photo-electric instrument; most recognizably a small electronic clip worn on the finger during hospital stays that measures oxygen saturation in the blood. It is attached to a medical monitor, via the clip, for staff to see a patient's oxygenation at all times and usually displays the heart rate as well.
This is a noninvasive method widely used in hospitals on newborns, patients with pulmonary disease, and those undergoing pulmonary and cardiac procedures. The pulse oximeter, like the Nellcor Systems N-595 Pulse Oximeter also measures oxygen levels and can be used during exercise, surgery or other medical procedures.
The pulse oximeter measures the difference between levels of the red pigment hemoglobin which carries oxygen in your blood. Oxygenated hemoglobin and non-oxygenated hemoglobin in your blood are two different colors.
To perform it's reading the finger clip has two light-emitting diodes – one that sends out invisible light and one red light. The monitored signal bounces in time with the heart beat because the arterial blood vessels expand and contract with each heartbeat.
By examining only the varying part of the absorption spectrum, subtracting minimum absorption from peak absorption, a monitor can ignore other tissues and discern only the absorption caused by arterial blood. Doctors find this information useful to figure out if your heart, lungs and blood are all working together to get oxygen delivered to all the various parts of the body.
Systems like the Nellcor Systems N-560 Pulse Oximeter are widely used in most hospitals and in research laboratories that study pulmonary function. Oximeters are used in hospital settings such as intensive care units, pulmonary units, and in health care centers. Nellcor Systems N-65 Handheld Pulse Oximeter portable hand-held devices are available, and are used to spot check patients for in-home use under the supervision of a physician.