Pediatric defibrillation doses often fail to terminate prolonged out-of-hospital ventricular fibrillation in children.
BACKGROUND
The recommended dose for pediatric defibrillation is 2 J/kg, based on animal studies of brief duration ventricular fibrillation (VF) and a single pediatric study of short duration in-hospital VF. In a piglet model of out-of-hospital (prolonged) cardiac arrest, this recommended dose was usually ineffective at terminating VF. We, therefore, hypothesized that pediatric dose defibrillation may be less effective for prolonged out-of-hospital pediatric VF.


METHODS
We evaluated retrospectively all cardiac arrests in children less than 13 years old in Tucson from November 1998 to April 2003, with special attention to all children in ventricular fibrillation. We determined the rate of ventricular fibrillation termination after pediatric dose shocks in this cohort, and compared this rate with a published historical pediatric in-hospital defibrillation control group. A pediatric dose shock was defined as 2 J/kg (+/-10 J). All shocks in both groups were provided as monophasic damped sinusoidal waveforms.


RESULTS
Thirteen of 151 (9%) children with out-of-hospital cardiac arrest had documented VF. Eleven children received a total of 14 pediatric dose shocks. The median minimum untreated dispatch-to-shock time in unwitnessed arrest or collapse-to-shock in witnessed arrest for those 11 children was 11 min (interquartile range 25-75%; 9-15.5 min). Seven of the 14 pediatric dose shocks terminated the VF (six to asystole, one to pulseless electrical activity). Nine children (68%) died in the emergency department and four (31%) in the pediatric intensive care unit; none survived to hospital discharge. Failure to terminate VF after a pediatric dose shock in this study group with prolonged out-of-hospital ventricular fibrillation was substantially more common than the previously reported in-hospital data (7/14 versus 5/57; OR 10.4; 95% CI 2.6-42; P=0.001).


CONCLUSIONS
Termination of VF after a pediatric defibrillation dose is substantially worse for prolonged pediatric out-of-hospital VF cardiac arrest compared with in-hospital (short duration) ventricular fibrillation. The optimal pediatric defibrillation dose for prolonged VF is not known.
Berg
Marc D
MD
Sarver Heart Center, University of Arizona College of Medicine, Tucson, AZ 85724, USA. marcb@peds.arizona.edu
Samson
Ricardo A
RA
Meyer
Robyn J
RJ
Clark
Lani L
LL
Valenzuela
Terence D
TD
Berg
Robert A
RA
D000293:Adolescent; D000367:Age Factors; D016887:Cardiopulmonary Resuscitation / Q000379:methods; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D047548:Defibrillators; D004554:Electric Countershock / Q000379:methods*; D004562:Electrocardiography; D004632:Emergency Medical Services; D005260:Female; D006323:Heart Arrest / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D006801:Humans; D008297:Male; D011336:Probability; D012016:Reference Values; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D015996:Survival Rate; D017211:Treatment Failure; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy*