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Epstein M, Rodan I, Griffenhagen G. AAHA/AAFP Pain Management Guidelines for Dogs and Cats. J Fel Med Surg 2015. 17, 251–272.
Guidelines are more extensive but focusing here on ECC scenarios with acute/short-term pain.
Update to the last set of guidelines published in 2007
“The recommendations of the Guidelines Task Force are evidence based in so far as possible and otherwise represent a consensus of expert opinion.”
1. Pain management must be central to our clinical practice
Part of initial assessment of emergency patients; address during initial stabilisation
Pain management important as it improves patient welfare – ethical and professional obligation; also has implications for clinical morbidity, progression, recovery and potentially outcomes.
Uncontrolled pain has both adverse psychological and physiological consequences.
2. Pain physiology should be considered when implementing our pain management
Pain response is unique to each individual.
Try as much as possible to individualise pain management; adjust and amend protocol based on individual patient’s response.
Staff must communicate to one another information about each individual patient’s pain response and management needs; verbal communication and in medical record.
“Pain is the endpoint of nociceptive input and can only occur in a conscious animal. However, there is also involvement of autonomic pathways and deeper centers of the brain involved with emotion and memory. Hence, pain is a multidimensional experience; it is not just what you feel but also how it makes you feel.”
Underlying causes of pain can be classified as:
- Nociceptive pain: occurs when peripheral neural receptors are activated by noxious stimuli (e.g. surgical incisions, trauma, heat or cold).
- Inflammatory pain: results gradually from activation of the immune system in response to injury or infection.
- Pathological pain, also called maladaptive pain: occurs when pain is amplified and sustained by molecular, cellular and microanatomic changes, collectively termed peripheral and central hypersensitisation or “wind up”.
- Sensitisation is characterised by hyperalgesia, allodynia, expansion of the painful field beyond its original boundaries and protracted pain.
- As far as wind up is concerned, anticipatory analgesia provided prior to pain onset is more effective than analgesia provided once pain has occurred. Get the pain of painful emergency patients under control as soon as possible and keep them as pain-free as possible.
Neuropathic pain can be considered a disease of the central nervous system.
3. The patient’s behaviour is key to pain assessment
Approach to pain management based on anticipating when pain is likely to be present, regular assessment, and at times making assumptions.
“It is now accepted that the most accurate method for evaluating pain in animals is not by physiological parameters but by observations of behavior.”
Use behaviour essentially as a means of non-verbal communication, to try and learn to interpret behaviour as tell-tale signs of on-going pain.
“Because behavioral signs of pain are often overlooked or mistaken for other problems, the healthcare team must be vigilant in recognizing those anomalies in the total patient assessment.”
4. Pain scoring tools can be useful
Improve objectivity in pain assessment and consistency between individuals.
But also ensures that regular pain assessment actually occurs!
“Although there is currently no gold standard method for assessing pain in dogs and cats, the Guidelines Task Force strongly recommends utilizing pain scoring tools both for acute and chronic pain. It should be noted that those tools have varying degrees of validation, acute and chronic pain scales are not interchangeable, and canine and feline scales are not interchangeable.”
5. Multimodal (balanced) analgesia is another key strategy in pain management
Use analgesic agents from different classes with the intention of targeting multiple points in the pain pathways.
Combining agents hopefully allows lower doses of each individual drug and thereby minimises potential for side effects associated with any single drug.
Some analgesic agents may work synergistically.
6. Opioids are the best analgesics in many emergency patients
“Opioids are the most effective drug class for managing acute pain”. More specifically the authors say that “Full µ agonists [– so drugs such as methadone, morphine, hydromorphone etc.] – elicit greater and more predictable analgesia than partial µ agonists or κ agonists. In dogs, the µ antagonist/κ agonist butorphanol, in particular, appears to provide limited somatic analgesia and a very short duration of visceral analgesia.”
Likely consensus that buprenorphine is a useful analgesic in mild-to-moderate or even severe pain. BUT has a comparatively slower onset of peak effect (20-45 minutes) compared to pure opioids so not ideal as first line analgesic in patients with moderate-to-severe pain.
7. Non-steroidal anti-inflammatory drugs (NSAIDs) may be contraindicated in emergency patients
“The majority of conditions that cause pain have an inflammatory component….NSAIDs should be used for their central and peripheral effects in both dogs and cats after consideration of risk factors. There is no indication that any one of the veterinary-approved NSAIDs is associated with any greater or lesser incidence or prevalence of adverse events.”
NSAIDs can be very effective; possible synergism with opioids in particular.
But potential contraindications relatively common in emergency patients – hypovolaemia, dehydration, significant gastrointestinal disease etc.
Guidelines also mention local anaesthetics, ketamine, systemic lidocaine, tramadol and a variety of other agents.
8. Don’t overlook non-pharmacological measures
“Increasingly, evidence-based data and empirical experience justify a strong role for non-pharmacologic modalities for pain management. A number of those should be considered mainstream options and an integral part of a balanced, individualized treatment plan.
Examples of non-pharmacologic treatments supported by strong evidence include, but are not limited to, cold compression, weight optimization and therapeutic exercise. Treatment options gaining increasing acceptance include acupuncture, physical rehabilitation, myofascial trigger point therapy and therapeutic laser….”
9. DON’T OVERLOOK TLC!
“Non-pharmacologic adjunctive treatment includes an appreciation of improved nursing care, gentle handling, care-giver involvement….There is strong evidence that the stress of hospitalization inhibits normal behaviors in animals, including eating, grooming, sleeping and elimination….Fear, anxiety, stress and distress lead to hyperalgesia in both humans and animals…Strategies to mitigate hyperalgesia, therefore, include providing bedding, blankets or clothing from home with familiar scents; allowing visitation of hospitalized pets; separating the dogs from the cats; placing cages so that animals do not see each other; using species-specific synthetic pheromones; and proper handling, especially during procedures”.
10. Conflicts of interest
“These Guidelines were supported by an educational grant to AAHA from Abbott Animal Health, Elanco Companion Animal Health, Merial and Zoetis.”
“Mark Epstein has previously consulted for Abbott, Elanco and Merial. Sheilah Robertson is a key opinion leader for Novartis Animal Health.”