A pulse oximeter is a mobile, non-invasive instrument that indirectly measures the oxygen saturation in a person’s blood. The device provides a reading which indicates the SpO2 (oxygen saturation) level and pulse rate of the user. Through an electronic display, the pulse oximeter shows how much oxygen is being carried in the bloodstream and thus being transmitted throughout the body.
Using a Pulse Oximeter
Who uses a pulse oximeter?
Oximeters are used by individuals who require regular monitoring of their oxygen level on a day to day basis. Pulse oximeters are used medically by doctors, nurses, dentists, EMTs and various other medical professionals who perform regular or periodic “spot checks” on patients. Persons using concentrated oxygen, or those with chronic illnesses of the respiratory or cardiac system benefit from knowing how well oxygenated they are. Oximeters can also be used for health monitoring by athletes, climbers, pilots and divers to guarantee they are getting properly oxygenated blood.
How does a pulse oximeter work?
An oximeter has a pair of small light-emitting diodes (LEDs) shining through a translucent part of the patient's body, usually a fingertip. One LED is red, and the other is infrared. Absorption of these wavelengths differs significantly between oxygenated blood and deoxygenated blood. The photodiode on the side opposite of the LEDs measures how much red and infrared light has been transmitted to calculate the oxygen saturation. In some pulse oximeters, the LEDs and the measuring photodiode are on the same side and a reflective technology is used to bounce the light waves back to the same side of the device.
Because blood circulates in momentary pulses, accurate measurements of oxygen levels adjust to the pulse rate, which is why pulse readings are also taken and displayed by a pulse oximeter.
There are two different methods by which light can be transmitted and read by a pulse oximeter. It has not been proven that one method is more effective than the other. Reflectance technology allows oximetry readings to be taken at more locations on the body, which could be helpful in a few unique situations.
Aside from differences in light detection, there are also differences in size, shape, and typical usage purposes between pulse oximeters.
Fingertip: Most common type used at home and outside of the clinic. They provide oximetry and pulse reading on the top of the area that clips onto the finger. Usually can run on AAA or AA batteries and can be transported easily because they are very light and small.
Handheld: Usually more sophisticated than a fingertip oximeter and are most commonly recommended for use at a clinic. They feature a fingertip sensor that is attached to a handheld display device. Care providers can monitor results, store and replay information, and use continuously as opposed to taking intermittent spot checks.
Wrist: Also provide a reliable reading for individual users, but use a display that attaches like a watch to a user’s wrist. They can make readouts and regular usage much easier for patients who do not wish to constantly carry around a fingertip oximeter.
Tabletop: Used frequently in labs and hospitals to monitor patients and conduct sleep studies. These also utilize fingertip probes that are attached to a hardware device which provides useful information to medical professionals. These are much bigger than other pulse oximeters.