Attenuating the defibrillation dosage decreases postresuscitation myocardial dysfunction in a swine model of pediatric ventricular fibrillation.
OBJECTIVE
The optimal biphasic defibrillation dose for children is unknown. Postresuscitation myocardial dysfunction is common and may be worsened by higher defibrillation doses. Adult-dose automated external defibrillators are commonly available; pediatric doses can be delivered by attenuating the adult defibrillation dose through a pediatric pads/cable system. The objective was to investigate whether unattenuated (adult) dose biphasic defibrillation results in greater postresuscitation myocardial dysfunction and damage than attenuated (pediatric) defibrillation.


METHODS
Laboratory animal experiment.


METHODS
University animal laboratory.


METHODS
Domestic swine weighing 19 +/- 3.6 kg.


METHODS
Fifty-two piglets were randomized to receive biphasic defibrillation using either adult-dose shocks of 200, 300, and 360 J or pediatric-dose shocks of approximately 50, 75, and 85 J after 7 mins of untreated ventricular fibrillation. Contrast left ventriculograms were obtained at baseline and then at 1, 2, 3, and 4 hrs postresuscitation. Postresuscitation left ventricular ejection fraction and cardiac troponins were evaluated.


RESULTS
By design, piglets in the adult-dose group received shocks with more energy (261 +/- 65 J vs. 72 +/- 12 J, p < .001) and higher peak current (37 +/- 8 A vs. 13 +/- 2 A, p < .001) at the largest defibrillation dose needed. In both groups, left ventricular ejection fraction was reduced significantly at 1, 2, and 4 hrs from baseline and improved during the 4 hrs postresuscitation. The decrease in left ventricular ejection fraction from baseline was greater after adult-dose defibrillation. Plasma cardiac troponin levels were elevated 4 hrs postresuscitation in 11 of 19 adult-dose piglets vs. four of 20 pediatric-dose piglets (p = .02).


CONCLUSIONS
Unattenuated adult-dose defibrillation results in a greater frequency of myocardial damage and worse postresuscitation myocardial function than pediatric doses in a swine model of prolonged out-of-hospital pediatric ventricular fibrillation cardiac arrest. These data support the use of pediatric attenuating electrodes with adult biphasic automated external defibrillators to defibrillate children.
Berg
Marc D
MD
University of Arizona Steele Children's Research Center, Tucson, AZ, USA. marcb@peds.arizona.edu
Banville
Isabelle L
IL
Chapman
Fred W
FW
Walker
Robert G
RG
Gaballa
Mohammed A
MA
Hilwig
Ronald W
RW
Samson
Ricardo A
RA
Kern
Karl B
KB
Berg
Robert A
RA
D000818:Animals; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation*; D006333:Heart Failure / Q000209:etiology; D013318:Stroke Volume; D013552:Swine; D014336:Troponin / Q000097:blood; D014693:Ventricular Fibrillation / Q000628:therapy*
D014336:Troponin