Resuscitation 67 (2005) 63–67 Pediatric defibrillation doses often fail to terminate prolonged out-of-hospital ventricular fibrillation in children  Marc D. Berg a,b,∗ , Ricardo A. Samson a,b , Robyn J. Meyer a,b , Lani L. Clark a , Terence D. Valenzuela a,c , Robert A. Berg a,b a Sarver Heart Center, University of Arizona College of Medicine, Tucson, AZ 85724, USA b Steele Memorial Children’s Research Center, Department of Pediatrics, Tucson, AZ 85724, USA c Department of Emergency Medicine, Tucson, AZ 85724, USA Received 19 January 2005; received in revised form 27 April 2005; accepted 27 April 2005 Abstract 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. © 2005 Elsevier Ireland Ltd. All rights reserved. Keywords: Ventricular fibrillation; Cardiac arrest; Heart arrest; Defibrillation; Children; Pediatric  A Spanish translated version of the Abstract of this article appears as Appendix at 10.1016/j.resuscitation.2005.04.018. ∗ Corresponding author. Present address: Steele Memorial Children’s Research Center, Department of Pediatrics, P.O. Box 245073, 1501 N Camp- bell Ave., Tucson, AZ 85724, USA. Tel.: +1 520 626 5485; fax: +1 520 626 6571. E-mail address: marcb@peds.arizona.edu (M.D. Berg). 1. Introduction Adult out-of-hospital cardiac arrests are commonly due to ventricular fibrillation (VF), so the initial focus is on prompt rhythm diagnosis and defibrillation [1]. In contrast, the initial electrocardiogram (ECG) for pediatric cardiac arrests usu- ally reveals a “non-shockable” rhythm, asystole or pulseless electrical activity [2]. Therefore, the initial focus for out-of- hospital pediatric cardiac arrests has been provision of rescue breathing and chest compressions; whereas rhythm diagnosis 0300-9572/$ – see front matter © 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2005.04.018