Animal Pulse Oximeters

Using spectrophotometry, pulse oximeters are a non-invasive method of measuring the oxygen saturation in percent in the hemoglobin of arterial blood. To achieve this, a probe simultaneously passes two different wavelengths of light through the tissues: red and infrared. Since oxygenated blood absorbs more of the infrared light, the result is more red light passing through. The opposite is true of deoxygenated hemoglobin, which absorbs more red light and allows more infrared to pass through the tissues. When the difference between the light absorption is calculated, you are left a percent often referred to as SpO2%.

Considerations with animal pulse oximeters

One of the things to consider is the placement of the probe. Typically, you want the area to have an arteriolar bed, be minimally-pigmented, and lack hair. Such places include the pinnae, prepuce, interdigital space and lips. There are also things which can interrupt or cause the oximeter to display false reading which need to be kept in mind. These include subject movement, highly pigmented skin, thin tissue areas, and interference, such as from extra light sources.