What is pain?
I am asked almost daily, “How do I know if my pet is in pain?” My response to this question is rarely brief and depends on many different factors. I have struggled over the years to come up with a simple answer. The reason for that is many pets do their best to avoid showing any symptoms at all, and when they do, the symptoms may be inconsistent, just like with people. This inconsistency can lead to misinterpreting the problem as resolved. I have collected some useful information through reading and experience, but even now, I rely on owners’ detailed histories and intimate knowledge of their pets’ routines as indicators of the problem’s source.
One obvious symptom of pain is avoidance of use, even if it’s inconsistent. However, the reliability of this symptom is quite low. In fact, it is common for pets not to display any symptoms while in our office due to excitement or fear (white coat syndrome). I regularly ask owners to take a video of their pet at home displaying the symptom. Additionally, we commonly perform imaging (radiographs, CT or MRI) to accurately diagnose problems due to a lack of consistent symptoms or as a means to plan a procedure. These tools, along with physical exam findings such as increased heart rate, respiratory rate, pupil dilation, panting, inability to find a comfortable and relaxed position, body posture, lip and ear position, and vocalization during manipulation, can all be indicators of pain. More objective measurements such as blood pressure, cortisol level, and reaction to painful stimuli can be useful in confirming a tentative diagnosis. Pain scales and measuring devices have also been used in research settings, but these are much harder to use in daily practice and are rarely used.
One of the primary responsibilities of a veterinary surgeon is to minimize or eliminate sources of pain such as torn ligaments, broken bones, or invasive tumors. Through a combination of surgery and medication administration, we are usually able to improve your pets’ comfort and potentially restore normal function. Unfortunately, to alleviate suffering, some level of surgical pain is commonly necessary.
A surgical approach to minimizing pain often begins days or weeks prior to the procedure. Using medications in categories like opioids, NSAIDs, steroids, and GABA analogs is useful in maintaining appropriate levels of comfort in anticipation of surgical intervention. These medications work quickly and synergistically to minimize painful stimuli and inflammation.
At the time of surgery, the approach to pain management in pets is very similar to how it is addressed in humans. The plan is traditionally divided into three separate categories: premedication, intraoperative, and postoperative medications are all considered for each case, with the timing of these medications adjusted based on the patient’s temperament and anticipated procedure-induced discomfort.
Premedication is usually given to relax the patient in combination with minimizing surgically induced discomfort. Multiple categories of medications are given concurrently, with each of them acting at different points in the pain pathway (multimodal analgesia). Once these medications have had time to work, the next phase of the procedure is initiated.
Many procedures require full anesthesia, so gas anesthetics are commonly used in veterinary surgery. These drugs have little to no pain-relieving properties. Therefore, most patients are maintained on some type of pain-relieving medication during the procedure. Intraoperative analgesia can be administered intravenously, locally, and even intrathecally (epidural). The dosage of these medications is calculated based on the patient’s body weight, preexisting medical conditions (heart disease, liver disease, anemia), genetic drug sensitivities, and anticipated procedural length.
Postoperative pain relief is divided into medications administered while in the hospital and those anticipated to be necessary following discharge. Most of these medications are administered orally. However, recent advances in pharmacology have allowed injections administered at the time of surgery to have a continued effect for up to three days. Transdermal administration is also commonly used in patients who may be difficult to medicate or have other reasons for avoiding oral administration. As with medications given during all phases, the goal is to interfere with pain development and progression both in the central nervous system and at the site of the operation.
Effective pain control and minimization of inflammation are essential components of successful surgical treatment. Understanding how pets display pain and the best ways to treat it are prioritized in all our patients. We rely on extensive and thorough communication with our pets’ owners to ensure the smoothest and pain-free recovery.