Defibrillation

Energy Doses for Pediatric Defibrillation During Resuscitation

Last Full Review: ILCOR 2025

In pediatric cardiac arrest cases, shockable ventricular arrhythmias—specifically ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT)—occur less frequently than nonshockable rhythms, such as asystole and pulseless electrical activity (PEA). However, when VF or pVT is present, the chances of survival are notably higher compared to nonshockable rhythms. Prompt defibrillation is crucial in treating these shockable rhythms, but there is ongoing debate regarding the optimal energy levels for both initial and subsequent defibrillation attempts. Some countries and resuscitation councils recommend 4 joules (J) per kilogram (kg) for the initial and subsequent shocks, while others recommend 2 J/kg or a range of 2 J/kg to 4 J/kg. A recent systematic review by the International Liaison Committee on Resuscitation (ILCOR) looked at the evidence for different initial energy doses for pediatric defibrillation.

 

Evidence Summary

A 2025 ILCOR systematic review (Acworth et al. 2025, 100991) and Consensus on Science with Treatment Recommendations (CoSTR) (Acworth et al. 2025; Scholefield et al.2025, S116) sought evidence for the use of an initial defibrillation dose of approximately 2 J/kg (1.5 to 2.5 J/kg) compared with an initial defibrillation dose of greater than 2.5 J/kg, less than 1.5 J/kg or any other specified dose in infants and children (excluding newborns) who are in VF or pVT during out-of-hospital or in-hospital cardiac arrest. Outcomes that were sought included survival to hospital discharge, return of spontaneous circulation (ROSC) and termination of VF/pVT. Seven observational studies were included in the review; the evidence from these studies was rated as very low certainty.

For defibrillation at less than 2 J/kg compared with defibrillation at approximately 2 J/kg, no significant difference was shown for survival to hospital discharge (two studies, 225 children) (Hoyme et al. 2020, 88; Rodríguez-Núñez et al. 2014, 387), for ROSC (four studies, 266 children) (Hoyme et al. 2020, 88; Rodríguez-Núñez et al. 2014, 387; Tibballs et al. 2011, 14; Tibballs et al. 2006, 310), or for termination of VF/pVT (two studies, 265 children) (Gutgesell et al. 1976, 898; Meaney et al. 2011, e16).

For defibrillation at greater than 2 J/kg compared with defibrillation at approximately 2 J/kg, no significant difference was shown for survival to hospital discharge (two studies, 225 children) (Hoyme et al. 2020, 88; Rodríguez-Núñez et al. 2014, 387), for ROSC (six studies, 596 children) (Hoyme et al. 2020, 88; Meaney et al. 2011, e16; Rodríguez-Núñez et al. 2014, 387; Rodríguez-Núñez et al. 2006, R113; Tibballs et al. 2011, 14; Tibballs et al. 2006, 310), or for termination of VF/pVT (two studies, 265 children) (Gutgesell et al. 1976, 898; Meaney et al. 2011, e16).

A weak recommendation by ILCOR suggests the use of an initial defibrillation dose of 2 J/kg to 4 J/kg for infants or children in VF or pVT cardiac arrest (Acworth et al. 2025; Scholefield et al. 2025, S116).

Insights and Implications

Data from currently available observational studies, while of very low certainty, suggest that the outcomes evaluated in this systematic review are not significantly better or worse with an initial defibrillation dose of less than 2 J/kg or greater than 2J/kg compared with an initial dose of approximately 2 J/kg. In most studies, the energy dose selection was limited by the defibrillator, and the dose used was either 2 J/kg or 4 J/kg. Current Red Cross guidelines call for an initial energy setting of 2 J/kg for shockable rhythms in children and infants, which is consistent with the ILCOR recommendations. The ILCOR review did not look at evidence for second or subsequent defibrillation doses. A 2020 ILCOR review (Maconochie 2020, S140) on this topic noted that there is insufficient evidence on which to base a recommendation for second and subsequent defibrillation doses. The Red Cross good practice statement for using an escalating energy dose for a second and subsequent shocks is based on expert opinion and is consistent with other resuscitation councils.

Single Versus Stacked Shocks for Pediatric Defibrillation

Last Full Review: ILCOR 2025
Last Update: 2010

Since 2010 the International Liaison Committee on Resuscitation (ILCOR) has recommended a single-shock strategy in pediatric patients with ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT) followed by immediate chest compressions. The previous three-shock strategy was recommended as older monophasic defibrillators had a low rate of conversion with the first shock, and it was thought that transthoracic impedance was reduced after each shock. This topic has not undergone a systematic review by ILCOR since 2010.

 

Evidence Summary

A 2024 ILCOR systematic review and Consensus on Science with Treatment Recommendations (CoSTR) (Tiwari et al. 2024; Scholefield et al. 2025, S116) sought evidence to support the use of more than one (stacked) shock(s) for the initial or subsequent defibrillation attempt(s) in infants and children who are in VF or pVT during in- or out-of-hospital cardiac arrest, compared with a single shock for each defibrillation attempt. Survival outcomes and return of circulation (ROC) were selected outcomes of interest for this review. The search failed to identify any pediatric trials, observational studies or case series comparing single versus stacked shock in children with cardiac arrest with VF or pVT in any setting. The previous 2005 ILCOR recommendation for delivery of stacked shocks was withdrawn for 2025, and a new good practice statement was made for infants and children with out-of-hospital or in-hospital cardiac arrest in VF or pVT that suggests a single-shock strategy followed by immediate CPR beginning with chest compressions (Tiwari et al. 2024 ILCOR; Scholefield et al. 2025, S116).

Insights and Implications

In discussion, the scoping review authors note that there is a first-shock success rate of up to 90% with current biphasic defibrillators, and that a stacked, three-shock sequence results in a delay of up to 37 seconds between the first shock and the first post-shock chest compression (Tiwari et al. 2024; Scholefield et al. 2025, S116). By using a single-shock strategy, if the initial shock fails, chest compressions may be provided, allowing delivery of oxygen to the myocardium and making the next shock more likely to result in defibrillation. The Red Cross guidelines continue to recommend a single-shock strategy for children and infants in cardiac arrest with a shockable rhythm and resuming CPR with chest compressions immediately following delivery of the shock and between any subsequent shocks.

Pad Size and Placement in Infants and Children

Last Full Review: ILCOR 2025

Standard manufacturer defibrillator electrode pads for adults are typically 8 to 12 centimeters (cm) in diameter, while for children and infants they measure around 7.0 cm x 11.2 cm. Pad sizes and shapes can vary by manufacturer, and some pads are the same size as adult pads but have an attenuator on the cord to step down the voltage applied to the pad. The proper position of automated external defibrillator (AED) or defibrillator pads should anatomically encompass the heart while ensuring good skin contact. An anterior-lateral position on the chest (avoiding breast tissue) or an anterior-posterior position have been recommended in past guidelines for adults, while for children and infants, an anterior-posterior position has been recommended. New studies have been published, triggering an updated systematic review by the International Liaison Committee on Resuscitation (ILCOR).

 

Evidence Summary

A 2025 International Liaison Committee on Resuscitation systematic review (Ristagno et al. 2025, 101030) and Consensus on Science with Treatment Recommendations (CoSTR) (Lopez-Herce et al. 2024; Scholefield et al.et al.2025 In Press), conducted with the ILCOR Basic and Advanced Life Support Task Forces, sought evidence with clinical outcomes for the use of any specific pad size/orientation and position in adults and children in cardiac arrest in any setting and with a shockable rhythm at any time during CPR, compared with the use of reference-standard pad size/orientation and position. No studies were identified for pediatric cardiac arrest. Studies from the adult population were used as indirect evidence.

For pad size, one observational pre-post implementation study (Yin et al. 2023, 109754) in adults did not find a significant difference in defibrillation success with a large pad size (113 centimeters [cm]²) compared with a small (65 cm²) pad size.

For pad position, two observational studies (Lupton et al. 2024, e2431673; Steinberg et al. 2022, 16) were identified studying different pad positions for adult out-of-hospital cardiac arrest (OHCA). The cohort study by Lupton et al. (Lupton et al. 2024, e2431673) was performed by a single emergency medical services agency with a protocol that initially placed pads in the anterior-posterior position, if feasible, with a change to the anterior-lateral position after three consecutive failed shocks. For the outcomes of favorable neurological outcome at hospital discharge and survival to hospital discharge, among 255 OHCAs, no significant benefit was shown from the initial anterior-posterior pad position compared with the initial anterior-lateral position. The same study found significant benefit for the outcome of return of spontaneous circulation (ROSC) from an initial anterior-posterior pad position compared with an initial anterior-lateral position (74.1% versus 50.5%; aOR, 2.64; 95% CI, 1.50–4.65).

A before-after study by Steinberg (Steinberg et al. 2022, 16) used recorded defibrillator data from OHCAs with initial ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT) to evaluate defibrillation success with anterior-posterior pad placement (207 patients, 1024 shocks) and subsequently with anterior-lateral (standard) pad placement (277 patients, 1,020 shocks). There was no significant difference in defibrillation success between the two pad positions.

For vector change, indirect evidence from adult studies were evaluated from a cluster-randomized controlled trial (Cheske et al. 2022, 1947) for refractory VF (persistent VF or pVT after three consecutive anterior-lateral defibrillations). Vector change was defined as defibrillation with a new set of pads placed in the anterior-posterior position for refractory VF. The trial compared vector-change defibrillation with standard anterior-lateral defibrillation in 280 adult OCHAs and was stopped early due to the coronavirus disease 2019 (COVID-19) pandemic. No significant difference was found for ROSC or survival to hospital discharge with favorable neurological outcome between the two groups. However, improved survival to discharge (21.7% versus 13.3%) and a higher rate of termination of VF (79.9% versus 67.6%; aRR, 1.18; 95% CI, 1.03–2.36) were both shown with vector change to anterior-posterior pad position compared with anterior-lateral pad position.

ILCOR developed good practice statements (Lopez-Herce et al. 2024; Scholefield et al.2025, S116) directed towards manufacturers of defibrillators including:

• Manufacturers should consider the standardization of pad size for infants, children and adults.
• Manufacturers of AEDs should standardize pad placement in an anterior-posterior position for infants and young children, with one pad anteriorly, over the left precordium and the other pad posteriorly to the heart just inferior to the left scapula.
• Manufacturers should include instructions to ensure proper contact between the pad and the skin and to ensure that their pad position diagrams clearly indicate the ILCOR-recommended pad positions.

 

For cardiopulmonary resuscitation (CPR) providers using an AED:

• A good practice statement advises following the AED’s specific guidance and instructions for pads placement in infants and children (Lopez-Herce et al. 2024; Scholefield et al.2025, S116).

 

For CPR providers trained in manual defibrillation:

• A good practice statement advises that for infants and children, pads should be placed in an anterior-posterior position as described above (Lopez-Herce et al. 2024; Scholefield et al. 2025, S116).

 

A recommendation could not be made for or against the use of vector change for the treatment of refractory VF or pVT in infants and children.

Insights and Implications

The Red Cross recommendation for the use of an anterior-posterior pad position in infants and children is unchanged and informed by the ILCOR treatment recommendations and the indirect evidence from adults that this pad position may improve ROSC. Placing pads in an anterior-posterior position is easier in infants and young children than for adults, so there should be little or no delay in defibrillation and chest compressions. Pads are often used as real-time feedback devices in pediatric cardiac arrest for assessment of the quality of chest compressions, and they typically require an anterior-posterior position for metric measurement. Vector change is currently not possible for children and infants due to difficulty fitting two sets of pads on a child’s thorax. In addition, the incidence of refractory VF in children and infants is not known.