Using Pain as a Clinical Parameter for Veterinary Patients

How can veterinarians use pain as a clinical parameter? Ralph Harvey, DVM, MS, DACVAA, previous associate professor of small animal clinical sciences at the University of Tennessee College of Veterinary Medicine, explains,

"With regard to using pain as a clinical parameter, it's been considered for some time now as either the fourth or fifth vital sign, if you will. And sometimes, the fourth final sign-if we do not include blood pressure-the fifth vital sign if you do so: temperature, pulse, respiration, blood pressure, and pain. So, pain is accepted as a fundamental characteristic of the welfare of the animal, if you will, and a parameter that needs to be evaluated.

The focus of my own discussion in today's symposium was on the recognition of clinical pain, the scoring or scaling of pain using validated systems, and sometimes systems that have not yet been validated but at least offer us a window of opportunity to assess the animal's pain and quite often those methods of assessing their pain are based on our ability to observe behaviors that the behavioral scientists have observed, have documented to be associated with pain. So, we look at a variety of different behaviors that are characteristic in dogs or cats or horses or cattle or pigs or research animals or, indeed, people. So, species-specific behaviors associated with pain. And we try to ascribe based on an accumulation of species-specific behaviors some sort of recognition-and it might be a graded recognition on a point system or a combination or composite point system. Many of those scoring implements or tools or devices, the systems have not been scientifically validated but they offer a way of assessing pain that relies on a subjective appreciation of observational behaviors.

There are some objective measures of pain that are becoming available now. One of them is the PainTrace device from the BioTraceIT corporation that will offer us the opportunity to measure pain in a quantitative fashion. In most instances right now, we are using these validated and sometimes non-validated subjective evaluations based primarily on the animal's behavior, and always tied to an interactive assessment. So, we'll not just look at the animal and observe it, actually go there and approach the animal, see how they respond to our approach and our touch and our hands-on evaluation."