If a person arrests in a hospital setting, their chance of survival to discharge is approximately 20%. In dogs and cats, that number drops to 6%.1 One of the reasons for this discrepancy is that human health care has evidence-based guidelines and requirements for routine training of professionals. In 2012, the veterinary community also received evidence-based guidelines titled RECOVER (Reassessment Campaign on Veterinary Resuscitation). These guidelines allow veterinary professionals to streamline their resuscitation and make it more efficient.
One of the most important factors in improving CPR outcome is one of the easiest to implement. Every hospital should have an “arrest station” including a fully stocked crash cart which is regularly maintained. Posters which outline the CPR algorithm as well as emergency drug dosages can be posted nearby (https://veccs.org/product-category/posters/).
Another important element is ensuring that the entire veterinary team is prepared for an arrest and is ready to intervene swiftly. This can be accomplished by in-hospital training and frequent review (RECOVER recommends every 6 months).1 During CPR, a team should be formed which contains a CPR leader, a compressor, a ventilator, a record keeper, and a drug handler.1 If fewer people are available, some of these jobs will need to be combined. Ideally, the compressor and ventilator will switch roles every two minutes to prevent fatigue.
Communication during and after CPR is also helpful to minimize mistakes and learn from each case. Closed-loop communication is recommended to cut down on errors. This occurs by the CPR leader requesting an action and the person being spoken to repeating back the request. When CPR is finished, it is also helpful to debrief. This allows for questions such as “what went well?” and “what could have been done differently?”.1.
Basic Life Support
When an arrest is suspected, a patient assessment should be completed quickly (no longer than 10-15 seconds). Because performing compressions in a patient who has not arrested is thought to cause minimal injury, CPR should occur immediately. We know that delaying the start of compressions can lead to a lower rate of return of spontaneous circulation (ROSC).
Chest compressions should be performed at a rate of 100–120 compressions per minute and should compress the chest by ⅓ to ½ of its width. Compressions should be performed in lateral recumbency with an exception for flat-chested dogs (ex: bulldogs), who can have better compression performed over the sternum (in dorsal recumbency). Because appropriate compressions only produce up to 30% of normal cardiac output, CPR should only be interrupted to assess the patient every two minutes (during this time, the compressor should switch out to avoid fatigue).2
Once compressions have been started, the airway should be evaluated. If more than one person is assisting in CPR, the patient should be intubated and ventilated at 10 breaths per minute. Hyperventilation should be avoided as a low CO2 level can cause vasoconstriction leading to decreased cerebral perfusion. If CPR is being performed by one person, mouth-to-snout ventilation can be used at a ratio of 2 breaths per 30 chest compressions.2
Advanced Life Support
Advanced life support encompasses the use of monitoring equipment, drug therapy, and defibrillation. The two forms of monitoring that prove useful during CPR is the electrocardiogram (ECG) and end-tidal carbon dioxide (ETCO2) monitoring.4 An ECG is useful to help determine whether the cardiac rhythm would respond to defibrillation and the ETCO2 gives you feedback on the efficacy of the compressions. If ETCO2 increases abruptly, ROSC is likely to have occurred. Other equipment such as non-invasive blood pressure monitors and pulse oximeters are not useful during CPR.
There are many drugs that can be used in CPR, but vasopressors are indicated regardless of what cardiac rhythm the patient has. Epinephrine is used to increase systemic vascular resistance, therefore helping to optimize perfusion. Low-dose epinephrine is advisable (0.01 mg/kg), with high-dose (0.1 mg/kg) being reserved for prolonged duration of CPR.3 Atropine has been shown to have little benefit, but there is also no evidence of harm.3 Specific types of arrest can also benefit from other treatments, such as reversal drugs during an anesthetic arrest and IV fluids if the patient is hypovolemic.
Electrical defibrillation is needed in patients with ventricular fibrillation or pulseless ventricular tachycardia. Defibrillation should only be performed in between compression cycles to minimize interruptions to compressions. This also allows time for the defibrillator to recharge.
Post CPR care:
If CPR is successful, the patient should be closely monitored and treated for possible complications as well as any underlying condition that may have led to the arrest. Preventing hypoxia/hyperoxia, maintaining hemodynamic stability, and treating increased cerebral pressure are all factors in goal-directed therapy.5 This type of care will often require 24-hour monitoring.
- Maureen McMichael, Jennifer Herring, Daniel J. Fletcher, et al. RECOVER evidence and knowledge gap analysis on veterinary CPR. Part 2: Preparedness and prevention.. J Vet Emerg Crit Care. 2012;22(Suppl 1): http://onlinelibrary.wiley.com/doi/10.1111/j.1476-4431.2012.00752.x/full
- Kate Hopper, Steven E. Epstein, Daniel J. Fletcher, et al. RECOVER evidence and knowledge gap analysis on veterinary CPR. Part 3: Basic life support. J Vet Emerg Crit Care. 2012;22(Suppl 1):S26–S43. S13–S25.http://onlinelibrary.wiley.com/doi/10.1111/j.1476-4431.2012.00752.x/full
- Elizabeth A. Rozanski, John E. Rush, Gareth J. Buckley, et al. RECOVER evidence and knowledge gap analysis on veterinary CPR. Part 4: Advanced life support. J Vet Emerg Crit Care. 2012;22(Suppl 1):S44–S64. http://onlinelibrary.wiley.com/doi/10.1111/j.1476-4431.2012.00755.x/full
- Benjamin M. Brainard, Manuel Boller, Daniel J. Fletcher, et al. RECOVER evidence and knowledge gap analysis on veterinary CPR. Part 5: Monitoring. J Vet Emerg Crit Care. 2012;22(Suppl 1):S65–S84 http://onlinelibrary.wiley.com/doi/10.1111/j.1476-4431.2012.00751.x/full
- Sean D. Smarick, Steve C. Haskins, Manuel Boller, et al.RECOVER evidence and knowledge gap analysis on veterinary CPR. Part 6: Post-cardiac arrest care.. J Vet Emerg Crit Care. 2012;22(Suppl 1):S85–S http://onlinelibrary.wiley.com/doi/10.1111/j.1476-4431.2012.00754.x/full