Introduction:
Pediatric sudden cardiac arrest may require the delivery of a defibrillating shock to promote return of spontaneous circulation (ROSC). Fear of harm is a barrier for the use of automated external defibrillators by lay personnel, particularly when the patient is a child. The aim of this study was to observe the effects of delivering pediatric defibrillation shocks to pediatric weight swine who are in a perfusing rhythm or ventricular fibrillation (VF).
Methods:
Eight swine (10.3-26.8 kg) were studied under anesthesia. Up to 30 shocks were applied using modified samaritan AEDs (HeartSine, UK) to animals either in sinus rhythm or after 30 seconds of VF. Shocks delivered in sinus rhythm were unsynchronized. Four different shock types were applied, utilizing two different waveforms (Waveform-A at 50 J, Waveform-A at 75 J, Waveform-A at 90J and Waveform-B at 50 J). Left ventricular (LV) pressures were recorded invasively (Millar, USA). If the shock was successful, the animal entered a rest period of approximately 5 minutes, after which the next shock was applied.
Results:
Data presented in Table 1. Out of a total of 77 shocks delivered in sinus rhythm, 2 (2.6%) resulted in conversion to a cardiac arrest rhythm. Analysis of LV pressures demonstrated no significant differences in the change of LV dP/dt from baseline at 1, 10 and 60 seconds post-shock. There was no significant difference in shock success or ROSC between the shock types for defibrillation of VF. Analysis of LV pressures demonstrated no significant differences in the change of LV dP/dt from baseline at at 1, 10 and 60 seconds post-shock between the groups.
Conclusions:
The results of this study indicate defibrillation shocks applied to swine in sinus rhythm rarely result in conversion to an arrhythmia. Additionally, the variety of shock types demonstrated similar levels of safety and efficacy in this porcine model.
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