With veterinary medicine offering ever higher levels of care, allowing sicker patients to be treated, witnessing cardiopulmonary arrest is not uncommon in practice and veterinary practitioners and their support staff should be ready to perform cardiopulmonary resuscitation (CPR). However, while hands-on training in veterinary CPR techniques is increasingly available, less emphasis has been placed on the importance of preparation at a practice level so that CPR can be initiated without delay. This article discusses some of these practical preparations and the importance of training the veterinary team to deliver effective CPR if needed.
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Alessandra Mathis qualified from the University of Perugia in Italy in 2003 and worked in general veterinary practice in Italy for three years. Having developed an interest in anaesthesia, she undertook an internship and then a three-year residency in anaesthesia and analgesia at the Royal Veterinary College in London during which time she gained the RCVS certificate in veterinary anaesthesia. She joined Willows Veterinary Centre and Referral Service in 2011 and became a Diplomate of the European College of Anaesthesia and Analgesia in 2012.
In a recent prospective study, McIntyre and others (2014) evaluated factors associated with the outcome of in-hospital cardiopulmonary resuscitation (CPR) in dogs and cats. They found that 58 per cent of patients attained return of spontaneous circulation (ROSC) but only 5 per cent were discharged alive from the hospital. In comparison, statistics published by the American Heart Association indicate that, in 2016, the survival rate (to hospital discharge) in human adult patients undergoing in-hospital CPR was 24.8 per cent (AHA 2016). Although many factors – including the actual cause of cardiac arrest and veterinary or human medical training (with the latter being more speciality specific) – play a role in generating this discrepancy, it is still undeniable that CPR (and post-CPR care) can and must be improved in small animal patients.
In 2012, the RECOVER (REassessment Campaign On VEterinary Resuscitation) Initiative presented a series of evidence-based consensus guidelines for veterinary CPR in cats and dogs (Fletcher and others 2012). These guidelines cover CPR-related topics in five domains:
Preparedness and prevention;
Basic life support;
Advanced life support;
Post-cardiac arrest care.
During the course of the RECOVER Initiative, major knowledge gaps were identified in many variables around cardiopulmonary arrest (CPA) and the success of CPR and the need for further studies was emphasised.
Training and preparation
Several differences between human CPR and veterinary CPR come to mind, including the level of monitoring and postoperative care available to patients, but a factor that is too often overlooked is the difference in training received by people performing CPR in human patients and those in the veterinary world. When CPR is taught in veterinary courses or conferences, most attention is naturally directed to basic and advanced life support; some is focused on post-CPR care, but very little is said about the importance of being prepared and effectively trained to perform CPR.
There is evidence from the human literature (Hoadley 2009) that training for CPR can improve patient outcome in many ways, including through better adherence to CPR guidelines.
Therefore, preparation for CPR therefore includes not only the process of setting up a ‘ready’ area where basic and advanced life support will be performed, but also ensuring personnel training and debriefing after any CPA or CPR (real or booster practical training session) effort has occurred. Optimising patient outcome requires a coordinated team with in-depth knowledge of the latest CPR guidelines, tidy, organised and functional equipment, and the ability to provide 24/7 post-ROSC care.
Any delay in starting CPR is associated with significant reductions in survival to discharge from hospital and with neurological status decay (Fletcher and others 2012). Having an area of the practice that is always ready, organised and functional for CPR will facilitate its initiation in a timely manner.
If a practice does not have an intensive care unit (ICU), this ‘ready’ area will often be the prep room or wherever the endotracheal tubes are stocked and readily available alongside kits to place intravenous (IV) cannulas and administer IV fluids. An easily accessible, organised crash trolley (Fig 1a, b, c) is the preferred option but, due to space restrictions, in most practices a crash box is adopted (Fig 1d). When the latter is used, it should contain only drugs and equipment that are not quickly reachable in the crash area (Table 1). If too much is stocked in a small box then it is difficult for it to be organised and valuable when it is needed. A compromise could be to use a plastic tower storage unit and label the different drawers as seen in Fig 1e.
The most frequent cause of equipment-related delay in initiating CPR is missing equipment (failure to return it after use, incomplete stocking, etc). Therefore, equipment and supplies must be prestocked and regularly audited (Fig 1f). Sealing the box or trolley (Fig 2) can help ensure that supplies are available and used only if needed.
Other factors that can also result in equipment-related delays include:
Basic device failure, such as intrinsic design faults;
External factors, such as power supply failure; and
Human error, such as an inability to use specific instruments. Staff must be familiar with the crash trolley or box (Fig 3) and must be trained in using the related equipment (such as the defibrillator) .
If there are several areas in the same practice or hospital where CPR may be performed (eg, the ICU and the prep room), the crash trolleys/boxes in each area should contain the same equipment in the same places, as this will minimise delays in finding the correct piece of equipment or drugs. Ideally, if multiple defibrillators are present, these too should be similar so as to diminish the need to learn how different equipment works.
Checklists and drug dosing charts are also very useful timesavers. Longer, more comprehensive, checklists have been shown to improve outcome over shorter checklists or no checklists at all (Ward and others 1997). Unfortunately, checklists are still rarely used in CPA situations. Bould and others (2009) found that the reasons for this include: lack of clarity of checklists; believing that checklists are unnecessary; lack of specifics; time pressure; unfamiliarity; difficulty of using a checklist in the middle of a CPR scenario; and disagreement with the content of a checklist.
The 2012 RECOVER guidelines (Fletcher and others 2012) contain a number of useful checklists and charts, including an algorithm delivering step-by-step prompts to the veterinary rescuer during CPR and summarising the most relevant clinical guidelines. A post-cardiac arrest algorithm is also available, summarising a comprehensive treatment protocol for post-cardiac arrest care. Finally, a CPR emergency drugs and doses chart provides a quick reference tool, with the drugs separated by indication (arrest drugs, antiarrhythmic drugs, reversal drugs and defibrillation energy) and the volumes required provided by bodyweight to help reduce calculation errors in stressful situations. However, before using this chart, veterinary professionals should check that the concentrations of the drugs in the chart correspond to those of the drugs in use in their practice.
According to the RECOVER guidelines, during the first two-minute cycle of CPR, drugs such as adrenaline should not be administered and only basic life support should be performed. Depending on the rhythm identified on the ECG at the end of the first cycle, adrenaline, lidocaine or atropine may be administered during the second two-minute cycle.
Some institutions prefer to have drugs preloaded into syringes and these are then discarded every week/month. The decision to preload syringes may be based on the number of staff available during CPR – if enough people are present then, to minimise wastage, drugs can be drawn up during the first cycle of CPR. However, if, at any time of the day, there are fewer than three people in the practice available to perform CPR, it would be advisable to preload drugs into syringes.
The stability of lidocaine and adrenaline in polypropylene syringes has been demonstrated for up to 90 days (Storms and others 2002, Rawas-Qalaji and others 2009), hence it would be advisable to store these for no more than a few months.
Data concerning atropine stored in polypropylene syringes are slightly less clear, with some studies showing a 50 per cent decrease in atropine concentration by day 3 (Lewis and others 1994) while others suggest that atropine is stable for up to eight days when stored into polypropylene syringes (Driver and others 1999).
In the light of these studies, it would be recommended to discard preloaded atropine every week.
High-quality basic life support consists of early recognition of CPA and administration of two-minute cycles of chest compressions and ventilation. The compressions must be of adequate rate and depth, with the giver’s hands and the patient properly positioned, and the ventilation provided must be adequate. Performing basic life support in an effective, organised manner requires both cognitive and psychomotor skills. In fact, the RECOVER guidelines state that ‘CPR training should be targeted at both cognitive performance and hands-on practice with quality feedback.’
The CPR team should be structured and should have a clear leader. In human medicine, there is no evidence that a more experienced team leader (ie, medically trained or not) improves the success of CPR (Olasveengen and others 2009) but there is compelling evidence, at least in simulation scenarios, that specific leadership training will improve CPR performance.
Leadership itself is difficult to describe but the main role requisite is being able to adapt and to coordinate tasks that change during the resuscitation process. Leadership skills can be better performed if an observing and coordinating role, rather than a hands-on role, is adopted during CPR. This will allow the leader to have a broader view on the situation and think about the steps required.
The leader’s first responsibility is, of course, to establish leadership. Following this, team members should be given roles as they arrive and, at the same time, basic life support should be implemented. The leader must also maintain a global perspective of the situation and ensure that the CPR guidelines are properly followed, prompting cooperation among the team members and minimising interruptions. The leader should step down and quickly and efficiently hand over leadership if a more competent individual becomes available to take over (Tschan and others 2014).
Successful leaders are extrovert, self-confident, flexible, calm and interested in improving team performance through training. These are the traits leadership training should aim to develop (Graham and others 2015).
Team training on CPR techniques must be standardised as this has been shown not only to improve success rates but also the feeling of competence in individuals performing CPR (McMichael and others 2012). In recent years, the awareness of CPR guidelines and the importance of hands-on training has been raised through teaching in vet schools and at conferences, as well as by recognised specific veterinary online courses.
In training for human CPR, high-fidelity manikins and other feedback devices have improved the initial learning of some of the psychomotor skills. These are not readily available for the veterinary market but some CPR dog manikins can be found. In these manikins, it is possible to place IV cannulas, intubate the trachea (Fig 5), inflate the lungs with ventilation and palpate femoral pulses. The most advanced manikins also have a light system indicating correct ventilation and compression pressure and correct hand position for chest compressions or beeps indicating excessive pressures.
Non-cognitive skills that should be taught during team training include clear closed-loop communication and standardised crash calls and cross-checks to ensure, for example, that other team members are clear of a patient before defibrillation.
In addition to initial CPR training, booster training is recommended to avoid deterioration of acquired skills. In fact, it has been shown that competency in CPR skills starts to deteriorate within weeks of learning, returning to pretraining levels within one to two years.
The RECOVER Initiative recommends refresher training at least every six months. Impromptu practice sessions (Fig 6) and refresher sessions using high-fidelity manikins can help to prolong the retention of psychomotor skills (Wik and others 2002).
In practices where a high-fidelity simulator is not available, simple simulations that run every three to six months on low-fidelity manikins will still improve the retention of CPR skills.
A structured performance assessment is recommended after every CPR training or refresher session. It has been shown that testing at the end of a resuscitation skills course for medical students increases learning outcome compared to spending an equal amount of time practising the skills (Kromann and others 2009).
Early debriefing after each real resuscitation attempt will improve individuals’ cognitive skills and also their CPR performance (Edelson and others 2008). Debriefing consists of allowing the individuals who participated in the CPR effort to critique their own and the team’s performance, identifying both their strengths and weaknesses.
Debriefing can also help identify factors that, if improved, may facilitate quicker, more effective and organised CPR in the future (eg, ECG leads tangled or hanging over the monitor, equipment to add or remove from the crash trolley, etc).
It is evident – mostly from human studies – that any delay in initiating CPR can have serious deleterious effects on the likelihood of ROSC. The keys to a prompt and effective response are having organised, prestocked arrest stations, a standardised training programme on high-fidelity manikins, including leadership and communication training, and, finally, post-CPR debriefing sessions.
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