In search of evidence in small animal emergency medicine - a speciality of its own
Over the last few years there has been increasing emphasis on the practice of evidence based medicine (EBM) in veterinary practice. Whilst there are detractors as well as proponents, EBM can only be beneficial for our patients. The value and practice of EBM has been recently discussed in this journal (Ness 2009) and rather than repeat its pros and cons, this editorial highlights how, and if, we can incorporate EBM into an area of veterinary medicine where the evidence base is limited, namely emergency medicine. There has been a growing interest in veterinary emergency medicine in recent years, an area traditionally not considered to be a speciality in its own right. With growing specialisation within disciplines – such as nephrology and urology – is it time to consider emergency medicine a speciality of its own? In medical practice it is well described that what you do at first presentation can make a difference to outcome.
Whilst there has been rapid expansion in the veterinary evidence base, in the smaller fields such as emergency medicine there is still little published information to guide decision making. The advent of pet insurance and wide availability of veterinary information on the internet has created more informed and demanding clients. Enhanced owner expectation is driving a need to improve the evidence base in areas such as emergency and critical care medicine.
Improving the evidence base
So how can we improve our evidence base? The Journal of Small Animal Practice covers the full scope of veterinary medicine. Looking through the articles from the last year there are numerous articles covering surgical, medical and imaging topics yet only a handful cover areas pertinent to emergency medicine (a subject relevant to most of the readership). This is not a criticism of the journal, it simply reflects a lack of submission of good quality articles in this area. Most articles published in veterinary journals come from specialist practices, only a few are published each year from general practice. Emergency medicine is a speciality of general practitioners and there is limited interest and scope in the veterinary specialist practices for research in this area. If we are to tackle this problem we need to start simply and look for answers to basic questions.
- •What are common emergency problems?
- •What common therapeutics are used in these situations?
There are a large number of studies on some common emergency topics such as gastric dilation and volvulus and urinary obstruction in cats. However many of these are retrospective studies and, rather than define best practice therapies, they are best used to describe patient populations, management techniques and measures of outcome. We need to ask how we can use this information. One retrospective showed that a high blood lactate concentration is associated with gastric necrosis and a poorer prognosis in canine GDV (de Papp and others 1999), but how do we apply this to our patient populations? In this case the information is probably best used to provide hypotheses for prospective evaluation rather than as a definite guide for clinical practice.
Applying our knowledge
Where information is available we need to ask how much of this can be applied to our own emergency patients? Similar to the case presented by Malcolm Ness in his recent editorial (Ness 2009), can we apply therapies that work in the hands of experts or experimental situations to real clinical practice where the practitioner may have differences in experience or equipment?
Much of the information in textbooks is based on clinical experience and experimental work. A lot of the knowledge of emergency medicine accrued by veterinary practitioners is experiential rather than based on EBM. Of course, experience is a form of evidence; unfortunately it is a form of evidence that breeds dogma. Whilst a sound understanding of the basis of disease can inform decisions there are some situations in which research has uncovered counterintuitive results. Ultimately many of us rely, not only on this learnt clinical knowledge, but also on a sound understanding of pathophysiology to allow us to make decisions without the need for experimental evidence – we all know it is a bad idea to jump out of a plane without a parachute (Smith and Pell 2005).
It would seem logical that 0·9% sodium chloride would be the most appropriate fluid choice in cats presenting with hyperkalaemia as a result of urethral obstruction (since many other isotonic fluids contain potassium). Yet a randomised prospective trial identified that administration of a balanced isotonic potassium containing fluid was associated with an equal rate of decline of blood potassium and conferred a potential benefit by more rapidly correcting the patient’s acid-case status (Drobatz and Cole 2008).
So how can we improve the evidence base in emergency practice? We are looking for small and subtle changes in patient populations that are not uniform. Studies need to have large numbers to show any kind of meaningful results. Single centre research in emergency medicine in the UK is challenging and suffers from a lack of clinical cases. Multi-centre research is even more challenging as it requires significant organisational input. Furthermore obtaining owner consent for clinical trials is challenging in the high stress emergency situation. This is not to say all is hopeless. All good quality research adds to the evidence base, even that showing negative results. So whilst it will be difficult we need to start somewhere, and maybe now is the time!
Sophie Adamantos is a lecturer in Emergency and Critical Care at the Royal Veterinary College. She is a diplomate of the American College of Veterinary Emergency and Critical Care and an RCVS recognised specialist in Emergency and Critical Care. She has worked at the Queen Mother Hospital for Animals within her specialty for the last 7 years where her main interest is emergency medicine. Her research interests include the clinical presentation of A. vasorum, particularly the effects of the parasite on coagulation.