Minimising risks of anaesthesia for exotic pets

Mixed and small animal practitioners are being presented with ‘exotic’ pets on an increasingly regular basis. Rabbits have been the third most popular mammalian pet in the UK for several years, but there is a lack of familiarity in treating them for some veterinarians as the popularity of the species is not always reflected in the amount of teaching on undergraduate courses. The problem is even more marked with less common species.

Far too often clients tell me that they’ve been told by the profession that ‘exotic’ anaesthesia is a risky endeavour. However there are as many, if not more, indications that anaesthetising ‘exotics’ enables a number of diagnostic and treatment procedures.

Advantages of exotic anaesthesia

It is important to be honest with clients and acknowledge that risk factors are often higher than they are for cats and dogs, but certainly not so high that things should not be attempted.

Information gained from a clinical examination of a number of ‘exotics’ can be limited, in comparison to that gleaned from domesticated species, subsequently we are more reliant on findings from diagnostic procedures. This only strengthens the need to anaesthetise as safely as possible, rather than not bothering at all. Indeed, for some exotics species/procedures it is much less stressful for the procedure to be carried out under anaesthesia in a controlled and safe manner.

More and more owners are, quite rightly, expecting the same level of care and treatment that their cats and dogs receive to be extended to their exotic pets, and the profession should be prepared and eager to meet these needs.

Is exotic anaesthesia really that risky?

The majority of exotic species do not readily show signs of illness, or at least signs that we recognise. Presumably this has developed alongside evolution to try to minimise predation, thus when an 'exotic' animal appears to be ‘acutely’ ill there is often a chronic component that has to be considered.

Unfortunately for a number of cases pathology may have progressed so far that the situation cannot be reversed and yes, for these individuals anaesthesia risks will be high, but in a number of ways that is no different than a similarly affected cat or dog - it’s just that sometimes we only find this out retrospectively.

However there are a number of things we can do to try to minimise the risks in the first place. One of these is suitable patient selection or pre-anaesthetic support.

Case study of a rabbit

A rabbit presents early in morning surgery with reduced appetite for the preceding few days. The owner is unsure if any faeces have been passed in the last 24 hours. The rabbit is a little quiet when presented, but there are obvious signs of excess salivation, and on oral examination there is an obvious lingual spur on the lower left arcade.

The rabbit is admitted and anaesthetised the same day to burr down the spur - sadly the rabbit does not survive the anaesthetic. More proof about how risky ‘exotic’ anaesthesia is? Not necessarily.

The rabbit is likely to be in a negative energy balance (hepatic lipidosis can start to occur as quickly as 10-12 hours in an anorexic rabbit). Fluid balance and gut function is also likely to be significantly affected, and from the above history ileum has probably started to occur. All these factors add up to significantly increased risk factors.

Not many of us would be happy to proceed with an anaesthetic on a dehydrated cat or dog that has not eaten for 5 days or more, unless absolutely necessary, without attempting to stabilise the patient first. It should be no different for the rabbit. With analgesia, fluid and nutritional support and use of appropriate pro-kinetics for a sufficient period pre-anaesthetic the anaesthetic, dental procedure and recovery can all be improved.

What about anaesthetising other exotic species?

Familiarity with anatomy, physiology and common problems of other species all help patient assessment and can reduce anaesthetic risk and mortality issues.

Oxygen uptake (hence gaseous anaesthetic) in birds is much more efficient than in mammals, but their ability to respire can be reduced up to 60% by poor positioning alone.

Respiratory drive for reptiles is not related to a build up of CO2 as it is in mammals, but a lack of oxygen. Thus the ‘drive’ to breath is often greatly reduced when volatile agents are used during anaesthesia, as the carrier gas is 90+% oxygen.

Ian Sayers

Learn more about exotic anaesthesia

Join us in Bristol on 9 June 2016 for High-risk exotic anaesthesia? It doesn't need to be - hear more about how to make anaesthesia safer for rabbits, rodents, ferrets, birds, reptiles and fish so that you can offer an improved service to meet your clients, and their pets', needs. 

You can also read Ian's In Practice articles Approach to preventive health care and welfare in rabbits and Phlebotomy in reptile and avian patients

Written by Ian Sayers
BVSc CertZooMed MRCVS RCVS Advanced Practitioner in Zoological Medicine

Ian's interest in ‘exotics’ started with keeping terrapins when he was 9 years old, which he continued to do for over 30 years. Since becoming a vet Ian has undertaken research work with cheetah in the Serengeti, worked at Bristol Zoo, and lectured around the world. He also taught at Bristol Veterinary School where he set up and ran the Rabbit Welfare Association and Fund clinic. Ian currently works at Silverton Vets whilst also offering support to Paignton Zoo and being a guest lecturer at the Royal Veterinary College.