BLS 2605 Anticipatory charging of the defibrillator: TF SR

Conflict of Interest Declaration

The ILCOR Continuous Evidence Evaluation process is guided by a rigorous ILCOR Conflict of Interest policy. The following Task Force members and other authors were recused from the discussion as they declared a conflict of interest: None applicable

The following Task Force members and other authors declared an intellectual conflict of interest and this was acknowledged and managed by the Task Force Chairs and Conflict of Interest committees: Ziad Nehme

CoSTR Citation

Nehme Z, Pocock H, Norii T, Olasveengen T, Bray J, on behalf of the International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force. Anticipatory charging of the defibrillator: a systematic review Consensus on Science with Treatment Recommendations [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force, 2025 December 1. Available from: http://ilcor.org

Methodological Preamble and Link to Published Systematic Review

This nodal review, conducted by the Basic Life Support (BLS) and Advanced Life Support (ALS) Taskforces, is the first systematic review on anticipatory charging undertaken by the International Liaison Committee on Resuscitation (ILCOR). A previous scoping review performed by the ALS Task Force in 2019 concluded that "anticipatory manual defibrillator charging appears to be feasible in the clinical setting, although its impact on clinical outcomes is uncertain."(Otto 2020) That review identified only one clinical study addressing anticipatory charging in in-hospital cardiac arrests, alongside three manikin-based simulation studies.

Since that time, additional studies have been published, including a clinical investigation conducted in the out-of-hospital setting.(Iversen 2021) Furthermore, studies that evaluated anticipatory charging as part of a high-performance cardiopulmonary resuscitation (CPR) bundle may have been overlooked in the earlier scoping review.(Nehme 2021) The previous review also focused exclusively on manual defibrillators, potentially omitting research related to anticipatory charging with automated external defibrillators (AEDs), such as the study by Partridge et al.(Partridge 2015)

In the present review, we updated the search strategy originally used by Otto et al.(Otto 2020) and conducted a comprehensive search from database inception through November 24, 2025. Both adult and pediatric populations were included. Due to the heterogeneity of the identified clinical and simulation studies, a meta-analysis was not performed. Instead, the results are presented as a qualitative synthesis of findings.

Systematic Review

Nehme Z, Pocock H, Norii T, Olasveengen T, Bray J, on behalf of the International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force. Anticipatory charging of the defibrillator: a systematic review [in progress]

PICOST

The PICOST (Population, Intervention, Comparator, Outcome, Study Designs and Timeframe)

Population: Adults and children with cardiac arrest in any setting

Intervention: Charging the defibrillator prior to rhythm analysis

Comparators: Charging the defibrillator after rhythm analysis

Outcomes: Survival to hospital discharge, 30 days or greater than 30 days with good neurological outcome, and survival to hospital discharge 30 days or greater than 30 days were ranked as critical outcomes. Return of spontaneous circulation (ROSC) and event survival was ranked as an important outcome. Other outcomes considered were defibrillation success, pre-shock pause, hands-off time, post-shock pause, peri-shock pause, compression-fraction, hands-on time and provider safety (inadvertent shocks).

Study Designs: Randomised controlled trials (RCTs) and non-randomized studies (non-randomized controlled trials, interrupted time series, controlled before-and-after studies, cohort studies) are eligible for inclusion. Unpublished studies (e.g., conference abstracts, trial protocols) are excluded. Manikin and animal studies exploring the impact of anticipatory charging on resuscitation quality outcomes (e.g. hands-off time) were also considered for inclusion. All relevant publications in any language are included as long as there is an English abstract.

Timeframe: Literature search was conducted from database inception to November 24, 2025

PROSPERO Registration CRD420251068149

Consensus on Science

A search strategy was executed using Ovid Medline, EMBASE and the Cochrane Central Register of Controlled Trials from their commencement to 24 November 2025. The search identified 268 non-duplicate titles, of which 33 studies were deemed relevant and underwent full-text review. We excluded 24 studies, including 14 conference abstracts. A total of 11 studies were eligible for the review, including two studies identified through snowballing of reference lists.

Of the 11 included studies, five were clinical studies in humans,(Iversen 2021, Nehme 2021, Alqudah 2022, Edelson 2010, Hopkins 2016) of which four involved out-of-hospital and one in-hospital cardiac arrest populations. All clinical studies were observational (retrospective) studies. None of the five studies included paediatric populations specifically. The remaining six studies included five randomised controlled simulation trials and one a non-randomised prospective simulation study.(Nehme 2021, Barash 2011, Coggins 2018, Hansen 2013, Kohn 2016, Kemper 2019)

Figure 1 (supplementary file) shows the methods of charging described in the included studies. Among the five clinical studies, five compared anticipatory charging to standard charging while two also compared anticipatory charging to the ERC/AHA2010 method. Three of the five clinical studies also involved bundled resuscitation interventions including the introduction of anticipatory charging.(Nehme 2021, Alqudah 2022, Hopkins 2016) Among the six included simulation studies, four compared anticipatory charging to standard charging while another three compared anticipatory charging to the ERC/AHA2010 charging method.

Due to significant variation in the interventions used, and the reporting of both adjusted and unadjusted differences for some outcomes, a meta-analysis was not undertaken.

CLINICAL STUDIES

Favourable neurological survival at discharge or 30-days

For the critical outcome of favourable neurological survival at discharge or 30-days, we identified very low certainty evidence (downgraded for risk of bias and indirectness) from one cohort study.(Hopkins 2016) In a retrospective study of 737 OHCA, patients receiving a bundled intervention including anticipatory charging were associated with higher risk-adjusted odds of neurologically intact survival at discharge (CPC 1 or 2) compared with patients not treated with the bundle (AOR 2.3, 95% CI: 1.3, 4.0).(Hopkins 2016)

Survival to hospital discharge or 30-day survival

For the critical outcome of survival to hospital discharge or 30-day survival, we identified very low certainty evidence (downgraded for risk of bias, indirectness and imprecision) from three cohort studies. (Iversen 2021, Nehme 2021, Alqudah 2022) In a before-and-after study of 178 adult OHCA patients, anticipatory charging was not associated with improved survival to hospital discharge compared with a combination of standard charging and the ERC 2010 charging method (absolute difference = 4.6%, 95% CI: -9.7%, 18.9%).(Iversen 2021) Conversely, two studies from Victoria, Australia, conducted over the same time period, including one involving 10600 adult OHCA (excludes EMS witnessed patients)(Nehme 2021) and another including 1981 EMS witnessed OHCA,(Alqudah 2022) found that the introduction of a bundle of care, including anticipatory charging, was associated with improved survival to hospital discharge compared with standard charging using semi-automatic defibrillation (AOR 1.33, 95% CI 1.11, 1.58 and AOR 1.37, 95% CI: 1.00, 1.88, respectively).

Return of spontaneous circulation (ROSC) and event survival

For the important outcome of return of spontaneous circulation, we identified very low certainty evidence (downgraded for risk of bias, indirectness and imprecision) from four cohort studies. (Iversen 2021, Nehme 2021, Alqudah 2022, Hopkins 2016) A before-and-after study of 178 adult OHCA patients found that anticipatory charging was not associated with improved ROSC compared with a combination of standard charging and the ERC 2010 charging method (absolute difference = –1.0%, 95% CI: –16.0%, 14.0%).(Iversen 2021) Another retrospective study of 10600 adult OHCA found that the introduction of a bundle of care, including anticipatory charging, was associated with improved ROSC (AOR 1.13, 95% CI: 1.01, 1.27) and event survival (AOR 1.21, 95% CI: 1.07, 1.36) compared with standard charging using semi-automatic defibrillation.(Nehme 2021) Another study from the same region/period,(Alqudah 2022) involving 1981 EMS witnessed OHCA, found that the introduction of the same bundle of care was not associated with improved ROSC (AOR 0.85, 95% CI: 0.67, 1.10) or event survival (AOR: 1.03, 95% CI: 0.80, 1.32) compared with standard charging using semi-automatic defibrillation. In another retrospective study of 737 OHCA, patients receiving a bundle of care, including anticipatory charging, achieved higher ROSC (absolute difference = 13.7%, 95% CI: 6.8% to 20.6%), but not event survival (absolute difference = 2.3%, 95% CI: –4.7% to 9.3%), compared to patients not treated with the bundle.(Hopkins 2016)

CPR quality

For the outcome of CPR quality, we identified very low certainty evidence (downgraded for risk of bias, indirectness and imprecision) from three cohort studies. (Iversen 2021, Nehme 2021, Edelson 2010)

• Pre-shock pause: Three studies reported on this outcome. One study identified a reduction in preshock pauses with anticipatory charging compared with the standard charging.(Iversen 2021) Another cohort study identified that a bundle of care including anticipatory charging was associated with a reduction in pre-shock pauses compared to the standard charging using semi-automatic defibrillation.(Nehme 2021) A study of in-hospital cardiac arrest found that anticipatory charging did not reduce pre-shock pauses compared with the ERC 2010 charging method, although a combination of anticipatory charging and the ERC 2010 method was associated with lower pre-shock pauses compared to the standard charging.(Edelson 2010)
• Post-shock pause: Two studies reported on this outcome. One study found that anticipatory charging reduced post-shock pauses compared to standard charging.(Iversen 2019) Two studies found no difference in post-shock pauses between the anticipatory and ERC2010 charging method.(Iversen 2021, Edelson 2010)
• Peri-shock pause: One study reported on this outcome and found that anticipatory charging reduced peri-shock pauses compared to standard charging, but increased peri-shock pauses compared to the ERC2010 charging method. (Iversen 2021)
• Chest compression rate and depth: Two studies reported effects on chest compression rate and depth. One study found that a bundle of care including anticipatory charging increased compression depth compared to standard charging using semi-automatic defibrillation, (Nehme 2021) while another identified that both the anticipatory and ERC2010 charging methods were associated with higher compression rates compared to standard charging.(Edelson 2010)
• Chest compression fraction: One study reported on chest compression fraction and found that anticipatory charging increased hands-on chest time compared with standard charging. (Iversen 2021)

Defibrillation safety

For the outcome of provider safety, we identified very low certainty evidence (downgraded for risk of bias) from one cohort study.(Edelson 2010) In a retrospective study of 225 in-hospital cardiac arrests, anticipatory charging was associated with similar rates of inadvertent shock administration compared with standard charging (absolute difference =1.5%, 95% CI: –1.4% to 4.4%) and compared with the ERC 2010 charging method (absolute difference = 1.5%, 95% CI: –1.4%, 4.4%).

SIMULATION STUDIES

CPR quality

For the outcome of CPR quality, we identified very low certainty evidence (downgraded for risk of bias and indirectness) from six simulation studies.(Partridge 2015, Barash 2011, Coggins 2018, Hansen 2013, Koch 2016, Kemper 2019)

• Pre-shock pause: Three studies reported on this outcome. Two identified a reduction in pre-shock pause with the use of anticipatory charging embedded into AED technology compared with standard charging, (Partridge 2015, Barash 2011) while another study found that anticipatory charging increased pre-shock pause compared with the ERC 2010 charging method. (Kemper 2019)
• Post-shock pause: Three studies reported on this outcome. Two identified no difference between anticipatory charging and standard charging,(Partridge 2015, Barash 2011) while another found that anticipatory charging increased post-shock pause compared with the ERC 2010 charging method. (Kemper 2012)
• Peri-shock pause: Three studies reported on this outcome. Two studies identified reductions in peri-shock pause with anticipatory charging compared to standard charging, (Partridge 2015, Coggins 2018) while another found that anticipatory charging increased peri-shock pause compared to the ERC 2010 charging method. (Kemper 2019)
• Total pauses: Four studies reported on total pauses, of which two studies reported reductions in total pauses for anticipatory charging compared to standard charging(Partridge 2015, Barash 2011) and another that compared to the ERC 2010 charging method.(Hansen 2013) Conversely, one study reported an increase in total pauses with anticipatory charging compared to the ERC 2010 charging method.(Kemper 2019)
• Chest compression rate, depth and recoil: Three studies reported effects on chest compression rate, depth and/or recoil.( Partridge 2015, Barash 2011, Koch 2016) These studies demonstrated no change in these metrics with anticipatory charging, with the exception of one study which showed lower chest compression rates among ALS providers using anticipatory charging embedded into AED technology compared with standard charging.(Barash 2011)
• Hands-off fraction: One study reported on hands-off fraction and showed that anticipatory charging reduced hands-off chest time compared to the ERC 2010 charging method. (Koch 2016)

Supplemental Tables: BLS 2605 Anticipatory charging Supp tables

Treatment Recommendations

We suggest charging a manual defibrillator during chest compressions, either before or after rhythm analysis (weak recommendation, very low certainty evidence). Both approaches require appropriate training to ensure safe and timely defibrillation with minimal pauses in chest compressions (good practice statement).

Justification and Evidence to Decision Framework Highlights

• Pauses in chest compressions during cardiac arrest are associated with poorer outcomes, including shock success and patient survival.(Cheskes 2011, Edelson 2006, Gundersen 2009) Animal studies indicate that around 90 seconds of chest compressions are required to raise coronary perfusion pressure to a level that optimises conditions for achieving ROSC following defibrillation.(Steen 2003) This pressure decreases when chest compressions are paused.(Kern 1998) Pauses for rhythm interpretation and defibrillation are the most significant source of interruptions in chest compressions.(Hanisch 2020) Such pauses may be due to human factors.(Abella 2006) To eliminate pauses during resuscitation, some health services and emergency medical services (EMS) have adopted a method of rhythm analysis that involves pre-charging the defibrillator in anticipation of rhythm analysis and defibrillation. The approach, known as anticipatory charging, differs to current practices where chest compressions are paused for both rhythm analysis and charging (known here as standard charging) or paused only for rhythm analysis before recommencing chest compressions during charging (the charging method described in the 2010 ERC/AHA guidelines).(Neumar 2010, Nolan 2010)
• This topic was prioritised for review by the BLS and ALS task forces as the topic was previously reviewed by ILCOR in 2019 and new evidence has emerged. Furthermore, studies reporting the effects of anticipatory charging as part of a bundle of care (Nehme 2021) were not included in the previous scoping review and the previous review focused on manual defibrillators and may have excluded some studies in AEDs using rhythm filtering technology.(Partridge 2015)
• We identified 11 studies, including 6 simulation studies and 5 cohort studies (no paediatric studies were found). The majority of included studies compared anticipatory charging to standard charging (e.g. pausing compressions for rhythm analysis and charging). Simulation and clinical studies suggest that anticipatory charging is feasible and can significantly reduce the duration of interruptions to chest compressions, compared with standard charging.(Iversen 2021, Partridge 2015, Barash 2011) Conversely, differences between anticipatory charging and the ERC/AHA 2010 charging method were inconsistent, with some studies reporting shorter hands-off chest delays with anticipatory charging,(Hansen 2013, Koch 2016) while others reported longer delays.(Iversen 2021, Kemper 2019) As such, the superiority of either method was uncertain.
• The effects of anticipatory charging on clinically important outcomes were also inconclusive. Those that reported positive associations with clinical outcomes involved bundles of care consisting of anticipatory charging and other major modifications to resuscitation. (Nehme 2021, Alqudah 2022, Hopkins 2016) These studies are limited by indirectness. The sample size in most clinical studies lacked the power to demonstrate clinically meaningful improvements in patient outcomes from modest reductions in CPR interruptions. (Iversen 2021, Edelson 2010) Importantly, the majority of these studies used standard charging as a comparator, and therefore the clinical benefit of anticipatory charging compared to the ERC/AHA 2010 method is not known.
• The Task Force balanced the importance of reducing interruptions to CPR with the likely cost and resource implications associated with training health care professionals and teams in the use of anticipatory charging. A survey of National Resuscitation Councils in Europe indicated that only 10% and 3% had implemented anticipatory charging into out-of-hospital and in-hospital resuscitation practice, respectively.(Ek 2025) Unlike standard charging, anticipatory charging likely involves greater training and resource burden to ensure teams are able to adequately implement safe defibrillation practices in high-performing environments. The use of mnemonics such as COACHED (Compressions continue, Oxygen away, All else clear, Charging, Hands off, Evaluate rhythm, Defibrillate or Disarm) are commonly used in practice but are often incorrectly applied.(Coggins 2018) Health care systems should consider the initial and ongoing training requirements of anticipatory charging.
• The majority of studies describing anticipatory charging involve manual defibrillation. Although it is generally not possible to undertake anticipatory charging using an AED, there are some simulation studies that explore the use of CPR filtering technology embedded into AEDs that allow pre-emptive charging and rhythm analysis during chest compressions. While the uptake of this technology in clinical environments is not widespread, the BLS Task Force has undertaken a separate review of the efficacy of rhythm analysis during chest compressions in another CoSTR.(Greif 2024) It is too soon to recommend the use of these technologies in clinical practice.
• The BLS and ALS task forces thought the inclusion of the good practice statement was needed to highlight the need for training in this practice ensure that it is performed safely (i.e. no inadvertent shocks occur while hands are on the chest) and pauses in chest compressions and time to defibrillation are minimised.
• Anticipatory charging is often introduced into practice as part of a bundle of practices designed to reduce hands-off chest time. These bundles are often referred to as high-performance CPR, team-focused CPR or minimally interrupted cardiac resuscitation.(Nehme 2021, Alqudah 2022, Hopkins 2016) The Task Force discussed the risk of indirectness with the inclusion of these studies, however, also acknowledged that there is unlikely to be further clinical studies exploring anticipatory charging as an isolated intervention. Their inclusion in this review has resulted in increased clinical heterogeneity between the included papers, and the effects of anticipatory charging reported in these studies should be interpreted with caution.
• Evidence on the safety profile of anticipatory charging remains limited. In theory, charging the defibrillator before rhythm analysis introduces a small but real risk of inappropriate shock delivery—either because the rhythm is misinterpreted under pressure or because the operator reflexively discharges the defibrillator once the device is ready. Existing studies suggest these events are uncommon, although most data come from one small observational study and may be too small to determine the real-world incidence inadvertent shocks. (Edelson 2010) There is also minimal evidence describing near-misses, human-factor errors, or unintended workflow consequences introduced by early charging. As a result, although anticipatory charging appears operationally safe, the actual risk of inadvertent shock or provider exposure is still poorly quantified. The small risk of a rescuer receiving an inadvertent shock may be minimised even further if all rescuers wear gloves. (Lloyd 2008)

EtD: BLS 2605 Anticipatory charging Et D

Knowledge Gaps

Current knowledge gaps include but are not limited to:

1. Although anticipatory charging reduces interruptions in CPR, robust evidence linking it to improved patient outcomes are still lacking.
2. Evidence is limited in how often anticipatory charging leads to adverse events (e.g. near-misses, incorrect shock delivery, or increased provider exposure to electrical risk).
3. While anticipatory charging can reduce peri-shock pauses, its real-world effect on hands-off time across different teams, systems, and levels of provider training remains poorly quantified.
4. The optimal method of charging and rhythm analysis remains unclear, and further comparisons are required between anticipatory charging and the ERC/AHA 2010 method.
5. Further studies are required to examine the impact of anticipatory charging on inappropriate shocks for asystole and pulseless electrical activity.

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