Overview

This fascinating webinar explores the importance of species specific analgesia. This is a great recap of how pain is felt with an in-depth look into the types of analgesic drugs available including how they work, most common uses and contraindications. The webinar also focuses on the importance of understanding behaviour. By knowing the subtle signs exhibited by both predator and prey species, this can allow us to stay one step ahead and reduce the detrimental effects that pain and stress can cause to the patient, both physically and mentally. It highlights the important link between analgesia and welfare as well as discussing a range of observational protocols and less traditional pain modifying treatments such as acupuncture and laser therapy.

Welfare Implications

The webinar starts with the very important reminder that the current WSAVA guidelines state that all animals should be given at least three days of post-operative analgesia as standard. Sadly, it has been found that this is only the case for about a third of cats and far less for exotics. This can partially be attributed to the fact that there are currently no UK licensed analgesic drugs and partially because many exotics are not considered to feel pain. However, there is research that clearly shows pain pathways for birds, reptiles, amphibians and fish do exist and pain relief should be provided. This research, as well as the efficacy of the different types of analgesia, is mainly based on anecdotal evidence but there are some evidence-based studies available. It is important to research thoroughly and this includes extrapolating from cat and dog research too.

Identifying Pain

Failing to recognise pain and/or failing to give appropriate analgesia directly lowers patient welfare. As such, it is vital that we understand how to identify pain. This is not as simple as purely monitoring the animal’s clinical parameters but needs an all-encompassing approach that includes assessing behaviour, posture, grimace and vocal cues to enable you to get the best understanding. This should be used in conjunction with a detailed patient history. It is important to know what is normal for the species and vitally, for the individual patient.

Predator vs Prey

Animals that are higher up the food chain are more likely to show obvious signs of pain or distress earlier, unlike prey species who avoid drawing attention to themselves, resulting in it being tricky to adequately assess the pain level of a prey animal. By the time they are showing obvious clinical signs then the disease process is already quite advanced. So, we need to be able to pick up on the more subtle indicators and this involves a lot of quiet observation, often more beneficial if undertaken from a distance. These subtle indicators are ‘inactive pain behaviours’ and comprise of things like twitching, wincing, flinching and belly pressing. These symptoms are often slight and fleeting at first and it takes patience and training to be able to spot them effectively. It is also important to remember that there will be a marked difference in how domesticated animals will show pain as opposed to their wild counterparts.

The Underpinning Science

Pain causes stress and distress and results in a physiological response. Molly describes what happens on a cellular level when tissues are damaged and the consequences of this. Acute stress releases adrenaline which triggers the body’s natural ‘fight or flight’ response. Blood will be diverted to the major organs whilst gut and urinary functions are slowed. This can have serious and sometimes fatal consequences in some species. We also need to consider chronic stress too. This results in an increase in cortisol levels which, over a prolonged period, can induce a range of problems including cardiomyopathy.

Therapeutic Considerations

An important step in choosing the correct analgesia is understanding how each drug works, its contraindications and which species it is suitable for. There is a fair amount of research showing that non-steroidal anti-inflammatories (NSAIDs) are well tolerated in most species. However, this becomes more difficult when looking at opiates because different species have different pain receptors. For example, birds have a different set of receptors to reptiles therefore morphine, methadone and fentanyl do not work as well. Reptiles are even more difficult as their receptors can also vary according to their breed.

Other medications

The use of tramadol, gabapentin and paracetamol is increasing and seem to be working well for many of the exotics. Paracetamol seems to be relatively safe, effective and has some published dose rates.

Constant rate infusions (CRIs) are generally underused and can provide excellent titrated analgesia. It is something that it worth considering if you have the relevant equipment already within the clinic.

Local analgesia is very well tolerated by most species and can be used in a variety of ways. Again, this is widely underused in practice. It is important to always be aware of the total safe dose for each patient and be careful not to go over this threshold.

Take Home Messages

1.   Species specific multimodal analgesia is vital for all patients

2.   Pain causes stress and distress, both leading to physical and mental problems

3.   Learn how each species shows normal, painful and stressed behaviours

4.   Understand the negative impact of pain so you can pre-empt it

5.   Consider using less traditional therapy (i.e. laser and physio) as well as medication

Reflection

As a result of this webinar, I will look into learning the specific behaviour traits of different species which will allow me to recognise the signs of pain and stress earlier. I can then combine this with the current pain scoring system to encompass more than one set of measured changes. I am interested in finding out more about combining alternative and traditional methods of pain relief to provide greater coverage. I hope to discuss my findings with the whole veterinary team and come up with a range of protocols for the different species that are seen most often.

Author

Jo Hinde RVN

Jo has worked in the veterinary industry since 2007 and has always had a special interest in rabbits. She started her own company LagoLearn, that provides rabbit specific CPD to veterinary professionals in both the UK and internationally She also spends a significant amount of voluntary time working with charities and parliamentary groups to highlight animal welfare and is proud to be a council member and officer of the British Veterinary Nurse Association. Jo attends many events, gives lectures and writes articles for the veterinary industry as well as the general public and schools. She has received several awards over the years including the Blue Cross Veterinary Nurse of the Year in 2014, an RCVS I
nnovation Award winner in 2017 and the IFAW Animal Advocate Award in 2017.

VOL 33 • October 2018 • Veterinary Nursing Journal