Page 36 - Feline Cardiology

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Cardiopulmonary Arrest and Cardiopulmonary

Cerebral Resuscitation

Key Points

• Whenever cardiac arrest is suspected, immediate measures to be taken include 1) confirming unconsciousness via stimulation,
and 2) placing intravenous catheter, endotracheal tube, and electrocardiographic (ECG) leads for monitoring.
• The cornerstone of treatment of ventricular fibrillation is immediate electrical defibrillation.

CARDIOPULMONARY ARREST provide the rhythm diagnosis during cardiac arrest, but
it is the combination of ECG and assessment of circula-
Popular culture equates cardiac arrest with asystole. This tion, including palpation of the pulse and measurement
misleading association conveys the impression that of the arterial blood pressure, that is necessary to confirm
cardiac arrest is purely a disorder of cardiac rhythm cardiac arrest and initiate treatment.
when in fact it is, more accurately, a disorder of cardiac Cardiopulmonary arrest (CPA) consists of cardiac
function: several arrhythmias are consistent with cardiac arrest with cessation of effective respirations. In feline
arrest. Cardiac arrest is the cessation of circulation, medicine, most cases of cardiac arrest evolve to CPA
depriving the vital organs of oxygen (ECC 2005). The within seconds or are preceded by respiratory arrest.
central feature of cardiac arrest is otherwise terminal
circulatory dysfunction regardless of cardiac rhythm. DIAGNOSIS
This end-stage circulatory collapse may occur with 1)
severe bradycardias/asystole (the most common cardiac Since it involves cessation of effective circulation and
rhythm in arrested small animal patients: 72%) (Waldrop respiration, CPA is recognized by loss of consciousness
et al. 2004; 2) severe tachycardias, during which the ven- and recumbency. A palpable pulse is not felt, the mucous
tricles cannot fill adequately during diastole and in membranes are pale or cyanotic, and respirations cease.
which case the heartbeat is ineffective because of In CPA, the blood pressure is too low to be measured
decreased stroke volume; or 3) relatively normal cardiac noninvasively. Electrocardiography may demonstrate a
rhythms in which the electrical activity of the heart is variety of rhythms (above) and should be used for
not translated into mechanical force of contraction (i.e., guiding therapeutic intervention during cardiopulmo-
pulseless electrical activity [PEA], formerly called elec- nary cerebral resuscitation (CPCR).
tromechanical dissociation, EMD). In other words, the DIFFERENTIAL DIAGNOSIS
ECG in cardiac arrest may demonstrate, respectively, 1)
asystole or bradycardias of sinus, atrial/junctional, or An important differential diagnosis for effective respira-
ventricular origin; 2) ventricular tachycardia (VT) or tions during arrest is agonal breathing. Agonal breaths
ventricular fibrillation (VF); or 3) sinus rhythm or other are defined by an opening of the mouth but no appre-
supraventricular rhythms when PEA is present (ECC ciable filling and emptying of the chest and, in intu-
2005; Rush and Wingfield 1992). The ECG alone can bated patients, no appreciable flow of air through the

Feline Cardiology, First Edition. Etienne Côté, Kristin A. MacDonald, Kathryn M. Meurs, Meg M. Sleeper.
© 2011 John Wiley & Sons, Inc. Published 2011 by John Wiley & Sons, Inc.

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