Pulse Oximeter, Capnograph Most Effective For Anesthesia

"Both the pulse oximeter and the capnometer, or capnograph—those tools are both probably most effectively used in patients under anesthesia," says Jamie M. Burkitt, DVM, DACVECC, assistant professor of clinical surgical and radiological sciences at the University of California, Davis.

"Pulse oximeters by far perform the best when the patient is completely still and the only movement signal that that processor has to think about is the pulsation of blood, which makes it very handy for animals under anesthesia who are not moving. Now granted, we always want to monitor pulse oximetry in animals that are anesthetized, but we would also really like to be able to use that monitor in animals that are awake and conscious pets. That can be a lot more challenging.

In those cases, we usually recommend using the toe or the toe web, the prepuce, or the vulva as the best spot to attach the clip, or to use a rectal probe-if you have a rectal probe-to monitor pulse oximetry. Those sites tend to be more reliable in the conscious animal than the lip or than the the pinna-the pinna is really, really unreliable.

The way that I would use them is in every anesthetized patient—the pulse oximeter in every anesthetized patient. And then ideally in any animal that comes into your emergency room that is having a difficult time breathing so that you can tell whether or not they really are hypoxemic, whether or not their pulse ox really is abnormal, and if it is abnormal, how abnormal is it? Then if you put oxygen on, does it respond?

The thing to remember of course is to minimize movement of the patient, and if they're asleep or you're able to, use the tongue-which is by far the best sight. If the tongue is not available, try the feet, actually, the prepuce and the vulva before you move to the lip and the ear."