Our enigmatic and mysterious webinar reviewer know only as The Stethoscope is back with another critique of a new webinar. Here, she discusses Cardiopulmonary resuscitation by Derek Flaherty.

Having spent several weeks watching the classic 1990’s series ‘ER’ with my husband, we feel we both know all there is to know about human CPR. The words ‘start chest compressions’, ‘IV adrenaline push’ and ‘bag him’ seem very familiar terms. But can we translate what happens in the human field over to veterinary medicine and has advice on how to effectively perform CPR changed over the years. Obviously deciphering the most up to date CPR policy based on ‘ER’ is not to be recommended. We have however learnt from the medical profession that formulating evidence based CPR guidelines is the best way to maximise your chances of a successful outcome. The RECOVER guidelines have been spearheaded by a team of veterinary emergency and critical care specialists and are the first evidence based veterinary CPR guidelines to be compiled. It is these guidelines along with some recent updates to human CPR which Professor Derek Flaherty BVMS,DVA,DipECVIM,MRCA,FHEA,FRCVS discussed within last weeks webinar offering a practical insight into how the whole veterinary team can respond effectively to a patient in cardiopulmonary arrest.

When to commence CPR seems like a sensible place to start with Professor Flaherty discussing how to assess a patient for cardiopulmonary arrest (CPA). Non responsiveness, apnoea, the absence of heart sounds and the absence of a palpable pulse are all signs consistent with a CPA. However it has been shown in the human field that even with experienced clinicians less than 2% can detect a pulse within 10 seconds. It has also been shown that in around 35 % of patients clinicians will think there is a pulse when in fact there isn’t one. For this reason, Professor Flaherty advises, if a patient is unresponsive and apneoic, chest compressions should be started straight away (this has shown only to have deleterious effects in 2% of people). Another assumption which could be drawn from watching one too many medical dramas is that the presence of fixed dilated pupils means the continuation of CPR is pointless. It has however been shown in monkeys that pupils can remain dilated for several hours post return of circulation indicating full resuscitation attempts should continue despite the presence of fixed dilated pupils.

Basic life support (BLS) should always be instigated when a CPA is suspected by implementing the A-B-C (airway, breathing, circulation) sequence. The order of this has however now changed to C-A-B in the human field as intubation in humans can be more challenging than animals and chest compressions will also result in compression of the lungs. It must also be remembered that CPA in humans usually results from cardiovascular disease which will be addressed to a certain degree with chest compressions. Cardiovascular disease is not a common cause of CPA in animals who are also usually much simpler to intubate compared to humans. For this reason Professor Flaherty advises still prioritising the establishment of a patent airway in animals alongside initiating chest compressions. The patient should be given 100% oxygen if possible at a rate of 10 breaths per minute regardless of its size. The position of chest compressions however will vary according to the size of the animal with hands being placed directly over the heart for patients less that 15kgs and compressions being performed at the widest part of the chest in animals larger than 15kgs (unless they are narrow chested animals such as sight hounds). Most animals are fine in left or right lateral recumbancy but barrel chested animals are really better being given sternal compressions in dorsal recumbancy. Compressions should be delivered at a rate of 120 compressions per minute whilst aiming to compress the chest by 30-50% allowing full recoil between each compression. This can be very tiring and compressors should be changed every two minutes.

Professor Flaherty went on to discuss the initiation of advanced life support (ALS) after implementing basic life support. This comes in the form of drugs for treating arrhythmias as well as electrical defibrillation. The presence of a specific arrhythmia needs to be assessed using an ECG and Professor Flaherty gave examples which included ventricular asystolie, pulseless electrical activity (PEA), pulseless ventricular tachycardia and ventricular fibrillation. PEA and asystolie are the most common arrhythmias in animals with ventricular fibrillation being the most common arrhythmia in people which has, unfortunately for the animal, but fortunately for the human, the best prognosis. Defibrillation is the treatment of choice for ventricular fibrillation and is why defibrillators are commonly used in humans and rarely useful in animals.

The use of drugs and fluid therapy was also integral to Professor Flaherty’s discussion. Intravenous fluid’s have been shown to be detrimental in euvolaemic animals as it has been shown to worsen the neurological outcome by increasing cerebral oedema and also decreases the blood pressure to the myocardium. For this reason intravenous fluid’s should only be given in cases of confirmed hypovolaemia. Due to its ability to maintain vasoconstriction and maximise blood flow to the brain and heart, Epinephrine is obviously a drug high on the list for use in patients with CPA. It is however very short acting and should be given very 3-5 minutes with Professor Flaherty suggesting administering epinephrine at every second compressor change. Doses for epinephrine were discussed in greater detail within the webinar. Atropine is another drug commonly used but Professor Flaherty stated that it has now been removed from the human guidelines for use in asystolie. However Professor Flaherty explained its use in animals is unlikely to be detrimental and may be of use in bradycardic animals prior to arrest and in bradycardic animals after the return of electrical activity. The use of vasopressin and sodium bicarbonate were also discussed within this webinar.

Professor Flaherty went on to discuss how we measure successful outcomes in CPR and how to maintain these patients once they have been resuscitated. The changes in human guidelines discussed by Professor Flaherty such as the avoidance of hyperoxaemia and the process of active cooling to reduce tissue oxygen demand make for fascinating listening and will hopefully transfer over to the veterinary sectors once more evidence becomes available. It is hoped that the RECOVER guidelines which were formulated in 2012 will be updated in 2020 and will make for yet another invaluable resource. This webinar also makes for an invaluable resource and it really is a watch I would highly recommend. It was even worth the sacrifice of an hour away from the talented Mr Clooney in ‘ER’.

Watch this webinar now!