Efficacy and Safety of Fixed-Energy (50-J) Biphasic Waveform Defibrillation in Pediatric Dogs with Cardiac Arrest
College of Veterinary Medicine, Kangwon National University, Chuncheon-si, Gangwon-do, Korea
There has been a report showing the effectiveness of transthoracic biphasic defibrillation for sudden cardiac arrest in dogs. However, most research focused on animal model studies to identify the optimal energy and shock waveform for human adults or children.
For adults, 150-J fixed-energy, impedance-compensating biphasic truncated exponential (ICBTE) shocks are now effectively used in automated defibrillators. However, the high energy levels delivered by adult automated defibrillators preclude their use for pediatric patients. Accordingly, we evaluated adult automated defibrillator (LIFEGAIN CU-HD1, CU Medical, Korea) adapted to deliver a 50-J ICBTE shock for pediatric defibrillation.
We initially investigated four groups of anesthetized, mechanically ventilated dogs weighing < 10 kg and between 10–20 kg. Ventricular fibrillation was induced with an AC current delivered to the right ventricular endocardium. After 7 min of untreated ventricular fibrillation, a conventional manual defibrillator was used to deliver up to three 50-J ICBTE shocks. If ventricular fibrillation was not reversed, a 1-min interval of precordial compression preceded a second sequence of up to three shocks. The protocol was repeated until spontaneous circulation was restored, or for a total of 15 min.
All animals were successfully resuscitated. Postresuscitation hemodynamic and myocardial function quickly returned to baseline values in both experimental groups, and all animals survived. Although there were transient elevations of cardiac biomarkers and serum enzymes related to myocardial damage, all these elevations returned to baseline values.
The 150-J biphasic adult automated defibrillators in which energy-reducing electrodes delivered 50-J shocks successfully resuscitated animals ranging from 3.6 to 20 kg without compromise of postresuscitation myocardial function or survival.