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: (insert names or declare none applicable) None APPLICABLE
Task Force Scoping Review Citation
Otto Q, Musiol S, Deakin CD, Morley PT, Soar J, on behalf of the International Liaison Committee on Resuscitation Advanced Life Support Task Force. Anticipatory defibrillator charging for ALS – manual defibrillation: Scoping Review and Task Force Insights [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) Advanced Life Support Task Force, 2020 Jan 3. Available from: http://ilcor.org
Methodological Preamble and Link to Published Scoping Review
The continuous evidence evaluation process started with a scoping review of adult life support conducted by the ILCOR ALS Task Force Scoping Review team.
Otto Q, Musiol S, Deakin CD, Morley PT, Soar J, on behalf of the International Liaison Committee on Resuscitation Advanced Life Support Task Force. Anticipatory defibrillator charging for ALS – manual defibrillation: A Scoping Review. In preparation.
The PICOST (Population, Intervention, Comparator, Outcome, Study Designs and Timeframe)
Population: Adults with cardiac arrest in any setting
Intervention: Charging the (manual) defibrillator prior to rhythm analysis
Comparators: Charging the (manual) defibrillator after rhythm analysis
Outcomes: Survival to hospital discharge, 30 days or greater than 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) 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, and hands-on time.
Study Designs: Randomized 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. Manikin studies were included for this scoping review, as was grey literature.
Timeframe: All years and all languages were included as long as there was an English abstract; unpublished studies (e.g., conference abstracts, trial protocols) were excluded. Literature search updated to 7 October, 2019.
Developed in liaison with Helen Pullen, Information Specialist at University Hospitals, Bristol
MEDLINE AND EMBASE via HDAS on 7/10/2019
(exp "HEART ARREST"/ OR exp "VENTRICULAR FIBRILLATION"/ OR heart arrest OR cardiac arrest OR asystole OR cardiopulmonary arrest OR cardiovascular arrest OR exp "CARDIOPULMONARY RESUSCITATION"/ OR resuscitation OR CPR OR “advanced life support” OR ALS OR "advanced cardiac life support" OR ACLS OR exp "HEART MASSAGE"/ OR heart massage*OR cardiac massage* OR Basic Life Support OR BLS OR cardiac rhythm) AND (("pre-charg*" OR "pre charg*" OR Anticipatory charg* OR Defibrillator charg* OR Defibrillation strateg* OR Defibrillation Sequence OR defibrillation algorithm OR shocking strateg* OR Shocking Algorithm OR COACHED OR "C.O.A.C.H.E.D." OR (prior ADJ3 charg*)).ti,ab)
COCHRANE on 7/10/2019
([mh “Heart Arrest”] OR [mh “Ventricular Fibrillation”] OR “heart arrest”:ab,ti OR “cardiac arrest”:ab,ti OR asystole:ab,ti OR “cardiopulmonary arrest”:ab,ti OR “cardiovascular arrest”:ab,ti OR [mh “Cardiopulmonary Resuscitation”] OR resuscitation:ab,ti OR CPR:ab,ti OR “advanced life support”:ab,ti OR ALS:ab,ti OR “advanced cardiac life support”:ab,ti OR ACLS:ab,ti OR “basic life support”:ab,ti OR BLS:ab,ti OR [mh “Heart Massage”] OR “heart massage*”:ab,ti OR “cardiac massage*”:ab,ti) AND ("pre-charg*":ab,ti OR "pre charg*":ab,ti OR Anticipatory charg*:ab,ti OR Defibrillator charg*:ab,ti OR Defibrillation strateg*:ab,ti OR Defibrillation Sequence:ab,ti OR defibrillation algorithm:ab,ti OR shocking strateg*:ab,ti OR Shocking Algorithm:ab,ti OR COACHED:ab,ti OR "C.O.A.C.H.E.D.":ab,ti OR prior NEAR charg*:ab,ti)
Inclusion and Exclusion criteria
Attachments:PRISMA Flow Diagram (see Figure 1 in appendix)Anticipatory Charging Appendices-PRISMA Figures Tables
Anticipatory defibrillator charging for ALS: A Scoping Review
Identified studies: 7/10/2019
Multi-centre, retrospective study, three US academic teaching hospitals
A total of 680 charge cycles from 244 in-hospital cardiac arrests involving 225 distinct patients, April 2006 to April 2009
Charging defibrillator prior to rhythm analysis
[If VF/pVT give shock]
N= 67 shocks
Charging defibrillator after rhythm assessment with ongoing chest compressions
N = 255
Results from anticipatory subgroup analysis. Median (IQR) in s
Post shock pause
Total hands off time in 30s preceding shock
No difference in inappropriate shocks, one shock to rescuer in anticipatory method, not causing interruption to CPR
See table 1 in appendix
Shock success, ROSC, Survival outcomes not reported from study
Study not designed to establish difference in AHA and anticipatory method, but compressions during charging.
Anticipatory charging had longer pre-shock pause but shorter total hands-off time in preceding 30s.
Lead author contacted for further data
Randomized Crossover Simulation Study. Regional hospital, Denmark.
Volunteer junior physicians confronted with simulated adult cardiac arrest, randomly assigned arrest rhythm of both pulseless VT (pVT) and asystole (AS). 10 physicians for comparison with ERC 2005 and 12 for ERC 2010
Charging the defibrillator while ongoing compressions, then pausing for rhythm check and shocking if indicated (pVT) or disarming if not (AS). 1) paddles used to compare to ERC 2005 2) Pads used to compare to ERC 2010
1) ERC 2005 guideline algorithm, pausing for duration of rhythm check through charging/shocking (if pVT) before continuing compressions. Paddles used. 2) ERC 2010 guideline algorithm, pausing for rhythm check, if pVT - compressions during charging and pause for shock before continuation of compressions
Hands-off-time (time without chest compressions) mean in s (95%CI).
Overall ERC 2005
pVT ERC 2005
AS ERC 2005 no difference
Overall ERC 2010 (this is what PICOST addresses)
AS ERC 2010 no difference p<0.1
No evidence of dangerous defibrillation
Intervention had shorter overall and shockable rhythm hands-off time compared to both ERC 2005 and ERC 2010. No difference in safety
MANUAL MONITORING OF HANDS OFF TIME
Randomized Controlled Single Centre Simulation Study.
243 Medical Students presented with randomly sequenced pulseless VT (pVT), VF or asystole (AS)
Anticipatory defibrillator charging (ADC)
ERC 2010 guideline algorithm (ERC), pausing for rhythm check, if VF or pVT - compressions during charging and pause for shock before continuation of compressions
No-flow time mean +/- SD
No differences in defibrillation safety
See table 2 in appendix.
ADC had longer peri-shock pauses, pre-shock pauses and post-shock pauses. ADC had shorter total pauses. No differences in safety
Koch Hansen, 2016
Randomized Crossover Simulation Study. Danish University Hospital
29 Volunteer cardiology physicians randomly assigned roles in an arrest team and confronted randomly with different arrest rhythms (pVT, VF, PEA, AS) in 11 simulated adult cardiac arrest scenarios. Oral command for control or intervention algorithm.
Stop-Only-While-Shocking (SOWS) - charging the defibrillator before rhythm check, while ongoing chest compressions
ERC 2010 guideline algorithm (ERC), pausing for rhythm check, if VF or pVT - compressions during charging and pause for shock before continuation of compressions
Mean hands-off time (expressed as per cent of entire simulation):
No inappropriate shocks
SOWS had lesser % hands-off time. No inappropriate shocks
- Edelson, D.P., Robertson-Dick, B.J., Yuen, T.C., Eilevstjønn, J., Walsh, D., Bareis, C.J., Vanden Hoek, T.L., Abella, B.S., 2010. Safety and efficacy of defibrillator charging during ongoing chest compressions: a multi-center study. Resuscitation 81, 1521–1526.
- Hansen, L.K., Folkestad, L., Brabrand, M., 2013. Defibrillator charging before rhythm analysis significantly reduces hands-off time during resuscitation: a simulation study. Am J Emerg Med 31, 395–400. https://doi.org/10.1016/j.ajem.2012.08.029.
- Kemper, M., Zech, A., Lazarovici, M., Zwissler, B., Prückner, S., Meyer, O., 2019. Defibrillator charging before rhythm analysis causes peri-shock pauses exceeding guideline recommended maximum 5 s. Anaesthesist 68, 546–554. https://doi.org/10.1007/s00101-019-0623-x
- Koch Hansen, L., Mohammed, A., Pedersen, M., Folkestad, L., Brodersen, J., Hey, T., Lyhne Christensen, N., Carter-Storch, R., Bendix, K., Hansen, M.R., Brabrand, M., 2016. The Stop-Only-While-Shocking algorithm reduces hands-off time by 17% during cardiopulmonary resuscitation - a simulation study. Eur J Emerg Med 23, 413–417. https://doi.org/10.1097/MEJ.00... width="1493" colspan="7" valign="top">
Anticipatory defibrillator charging for ALS: A Scoping Review Possible papers of relevance/Relevant Posters/Abstracts/Letters Search on: 7/10/2019
[will move to appendix]
- Barash, 2011.
Randomized Crossover Simulation Study. USA
Thirty providers confronted with simulated adult cardiac arrests. 10 ALS Paramedics, 9 BLS medical technicians, 10 BLS lay rescuers and 1 BLS nurse.
Analysis and Charging during CPR mode (AC-CPR) [B in fig below]
See Figure 2 in appendix.
Manual defibrillation CPR (ALS providers); Automated defibrillation CPR (BLS providers)
Duration of interruptions in chest compressions during whole resuscitation. Mean =/- SD in s:
- AC-CPR (ALS) = 43.2 +/- 7.3 vs ALS = 104.2 +/- 30.6; p = 0.005
- AC-CPR (BLS) = 42.6 +/- 15/9 vs BLS = 108.5 +/- 17.2, p < 0.0001
- AC-CPR (ALS) = 3.0 +/- 1.2 vs ALS = 10.2 +/- 1.9, p < 0.0001
- AC-CPR (BLS) = 1.7 +/- 0.5 vs BLS 11.3 +/- 0.8, p < 0.0001
- AC-CPR (ALS) = 4.4 +/- 2.5 vs ALS 6.8 +/- 4.1, p = 0.2
- AC-CPR (BLS) = 5.8 +/- 2.0 vs BLS 4.9 +/- 2.0, p = 0.3
No differences in perceived exertion or pain
The intervention also encompasses automated rhythm analysis, and BLS modes. Sponsored by Zoll, two authors employed by Zoll, manufacturers of the technology used.
AC-CPR (ALS) had shorter interruptions in whole arrest and shorter pre-shock pause .
- Coggins 2018
Cohort single-blinded study in Australian University Hospital
112 Hospital ALS providers undergoing manikin training for mechanical CPR, assessed on defibrillation practice (blinded). 109 defibrillations over 6 months
Correct or ‘near correct’ use of C.O.A.C.H.E.D cognitive aid
Incorrect or absent use of cognitive aid
The C.O.A.C.H.E.D. cognitive aid was applied correctly in 92 of 109 defibrillations. Providers with correct cognitive aid use had a median length of peri-shock pause time of 6.0 s (IQR 5.0–7.0). Providers with ‘entirely incorrect or absent’ cognitive aid use had a peri-shock pause time of 8.0 s (IQRF 6.6–10.0)(p ≤ 0.001). No unsafe defibrillation practices were observed.
The C.O.A.C.H.E.D aid used correctly reduces peri-shock pause time. No unsafe defibrillation attempts.
- Iversen 2019
A feasibility study introducing defib Pre-charge through short theoretical and practical lectures, followed by simulated arrest.
Pre-hospital practitioners in simulated adult (assumed) cardiac arrests, after teaching session on pre-charging.
Pre-charging the defibrillator before rhythm check
Any other sequence of action or practice, as judged by two consultant observers
Pre-charge was adequately used in 95 of 99 cases. One 'near-miss' shock in case of a non-shockable rhythm.
Small study of a short training programme to learn new method. Outcomes measured of limited value.
- Studnek, 2012
This was a retrospective analysis of data obtained from a single ALS urban EMS system from 1/1/2010 to 12/31/10 and 8/1/11 to 11/6/2011
Paramedics in EMS system treating adult patients who required at least one defibrillation and had the CPR feedback device connected during the defibrillation attempt
Charging the defibrillator after 180 compressions and pausing for rhythm check +/- shock at 200 compressions (anticipatory charging)
Current practice (not described) assumed no compressions during charging. Author contacted.
pre-intervention was 35 seconds (95% CI 20-50) post-intervention duration was 9 seconds (95% CI 7-12) p<0.001
Continuation of compressions during charging reduces pre-shock pause.
- Thim, 2012
Letter to Editor
Randomised controlled crossover study
Six physician volunteers (ALS) confronted with VF arrests (but told to expect any rhythm)
Standard ERC2010 guidelines
- Absolute difference in time interval between 2 CPR cycles: 7.3 s (95% CI 4.3 - 10.3); Difference in hands-off time 1.5 s (0.4 - 2.5 s); Favouring Pre-charging
See Figure 3 in appendix.
Pre-charging shortened the total time and
hands-off time between CPR cycles
- Boushra 2019
Retrospective single-centre cohort study
102 patients over a three-year period with OHCA who presented with a shockable rhythm and received at least one shock
Pre-charging the defibrillator before rhythm check
Any other method of defibrillation (author response – ‘majority’ performed compressions during charging (‘back on the chest’)
25 of 102 enrolled patients survived to hospital discharge. Pre-charging was associated with decreased time from rhythm analysis to shock delivery by 12.73.5 [typo in original abstract] seconds (p=.0004). No correlation was found between pre-charging and time to ROSC (p=.4518), number of shocks delivered (p=.925), or neurological outcome (R-square=0.025) [blinded modified Rankin score]
Unsurprising relationship between time from rhythm analysis to shock delivery. No other benefit found from this small study. Sample size n=25 Useful outcome data limited. Authpr contacted. Working on full paper. Not quite sure what comparator group is.
- Barash, D.M., Raymond, R.P., Tan, Q., Silver, A.E., 2011. A new defibrillator mode to reduce chest compression interruptions for health care professionals and lay rescuers: a pilot study in manikins. Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors 15, 88–97.
- Coggins A, Nottingham C, Chin M, Warburton S, Han M, Murphy M, et al. A prospective evaluation of the ‘C.O.A.C.H.E.D.’ cognitive aid for emergency defibrillation. Australas Emerg Care. 2018 Aug;21(3):81–6.
- Iversen B.N., Alstrup K., Faurby R., Christensen S., Kirkegaard H., 2019. Introducing pre-charge in the pre-hospital setting: A feasibility study. Acta Anaesthesiologica Scandinavica 63.
- Studnek J., Hawkins E., Vandeventer S., 2012. The impact of an educational intervention on the pre-shock pause interval among patients experiencing an out-of-hospital cardiac arrest. Academic Emergency Medicine 19.
- Thim, T., Grove, E.L., Løfgren, B., 2012. Charging the defibrillator before rhythm check reduces hands-off time during CPR: A randomised simulation study. Resuscitation 83, e210–e211. https://doi.org/10.1016/j.resuscitation.2012.07.034
- Boushra M., Dixon M., Coco M., Stahl J., Brewer K.L., Taylor S.E. Defibrillator precharging does not improve survival or neurological outcome in prehospital cardiac arrest. Academic Emergency Medicine. 2019 May;26.
Task Force Insights
1. Statement about why this topic was reviewed.
- This new topic was chosen because some resuscitation systems have adopted the anticipatory charging approach for manual defibrillation.
- There is debate about this topic: [Sam Ghali, "Beyond ACLS: Pre-Charging the Defibrillator", REBEL EM blog, March 24, 2016. Available at: https://rebelem.com/beyond-acls-pre-charging-the-defibrillator/. ]
- This scoping review aims to identify the available studies on this topic, and whether a systematic review is required.
2. Narrative summary of evidence identified
- There are currently insufficient studies to support progressing to a systematic review on this topic.
- We identified no randomised controlled clinical trials in humans addressing this topic.
- The single human observational study [Edelson 2010 1521] did not report ROSC or survival outcomes.
- The human [Edelson 2010 1521] and manikin studies [Hansen 2013 395, Kemper 2019 546, Koch-Hansen 2016 413] suggest that charging the defibrillator in anticipation of the rhythm check, and shocking or disarming as appropriate increases the immediate pre-shock pause, and the peri-shock pause, but decreases the total number of pauses and hands off time.
- Anticipatory charging may be a method to reduce the overall compression pause time during cardiac arrest, but may result in longer immediate pre and peri-shock pause times.
- We do not know which combination of these pauses is most important. Peri-shock pause is an important metric associated with key outcomes during resuscitation. Longer pauses worsen outcomes [Cheskes, 2011 124, Cheskes 2014 336]. A shorter pre-shock pause is associated with increased defibrillation success [Edelson 2006 136].
- Direct comparison of peri and pre-shock pauses between current methods are difficult and may not be valid.
- One manikin study showed that the post-shock pause time is longer with anticipatory charging [Kemper 2019 546].
- The available studies did not identify any safety issues between the different defibrillation strategies.
- These defibrillation strategies are primarily for a pads-based approach for manual defibrillation [need to highlight those studies that used paddles]
- We have also reviewed abstracts, posters, letters and related publications and these do not provide any new information.
- Other relevant studies to this subject
- It appears safe and feasible to charge the defibrillator in anticipation of a rhythm check in and out of hospital, and cognitive aids have been used successfully in resuscitation systems to achieve this [Coggins 2018 81, Iverson, 2019].
- An observational study in real cardiac arrests reported that long pauses before defibrillation are likely due to human factors during the resuscitation and not due to inherent difficulties with rhythm identification [Abella 2006 S427].
- A randomised manikin study showed that ‘Hands-on time and time to defibrillation’ are worse with ad-hoc teams or when leadership is poor [Hunziker 2009 3]. The techniques may work differently for different teams.
- We did not specifically look at:
- New defibrillator technologies that filter the effect of movement during chest compression – these defibrillators are designed to analyse rhythm without pausing chest compression. They are not part of this question. This type of defibrillator removes the need to analyse rhythm and enables charging during chest compression when the rhythm is identified as shockable.
- How long it takes for the defibrillator to charge – modern defibrillators charge very rapidly – if chest compressions are given during charging only this leads to very few chest compressions. Should there be a specific period of chest compressions before giving shock in current commonly used approach? This would have to be less than the time for the defibrillation ‘dumping the charge’ if no shock is delivered after charging.
- The TF decided there was insufficient information at this time to warrant a formal systematic review.
- There are no studies that look at critical or important outcomes.
- This topic is redundant in those settings that use defibrillators that can analyse during chest compression – this function is currently not commonly used.
- The usefulness of approaches depends on skills of individual using the defibrillator.
- The charging prior to rhythm analysis approach is taught in Australia, New Zealand and in some parts of Europe and North America.
3. Narrative Reporting of the task force discussions
Knowledge Gaps Template for Task Force chairs
There were no RCTs identified, and little in the way of observational clinical data on this topic. The relative importance of different pauses, (e.g. pre-, post-, peri-shock, compression fraction) is not known.
Abella, B.S., Kim, S., Edelson, D.P., Huang, K.-N., Merchant, R.M., Myklebust, H., Vanden Hoek, T.L., Becker, L.B., 2006. Difficulty of cardiac arrest rhythm identification does not correlate with length of chest compression pause before defibrillation. Crit. Care Med. 34, S427-431. https://doi.org/10.1097/01.CCM.0000246757.15898.13
Barash, D.M., Raymond, R.P., Tan, Q., Silver, A.E., 2011. A new defibrillator mode to reduce chest compression interruptions for health care professionals and lay rescuers: a pilot study in manikins. Prehosp Emerg Care 15, 88–97. https://doi.org/10.3109/109031... M., Dixon M., Coco M., Stahl J., Brewer K.L., Taylor S.E., 2019. Defibrillator precharging does not improve survival or neurological outcome in prehospital cardiac arrest. Academic Emergency Medicine 26.
Cheskes, S., Schmicker, R.H., Christenson, J., Salcido, D.D., Rea, T., Powell, J., Edelson, D.P., Sell, R., May, S., Menegazzi, J.J., Van Ottingham, L., Olsufka, M., Pennington, S., Simonini, J., Berg, R.A., Stiell, I., Idris, A., Bigham, B., Morrison, L., 2011. Peri-shock pause: an independent predictor of survival from out-of-hospital shockable cardiac arrest. Circulation 124, 58–66. https://doi.org/10.1161/CIRCULATIONAHA.110.010736
Cheskes, S., Schmicker, R.H., Verbeek, P.R., Salcido, D.D., Brown, S.P., Brooks, S., Menegazzi, J.J., Vaillancourt, C., Powell, J., May, S., Berg, R.A., Sell, R., Idris, A., Kampp, M., Schmidt, T., Christenson, J., 2014. The impact of peri-shock pause on survival from out-of-hospital shockable cardiac arrest during the Resuscitation Outcomes Consortium PRIMED trial. Resuscitation 85, 336–342. https://doi.org/10.1016/j.resuscitation.2013.10.014
Coggins, A., Nottingham, C., Chin, M., Warburton, S., Han, M., Murphy, M., Sutherland, J., Moore, N., 2018. A prospective evaluation of the “C.O.A.C.H.E.D.” cognitive aid for emergency defibrillation. Australas Emerg Care 21, 81–86. https://doi.org/10.1016/j.auec.2018.08.002
Edelson, D.P., Abella, B.S., Kramer-Johansen, J., Wik, L., Myklebust, H., Barry, A.M., Merchant, R.M., Hoek, T.L.V., Steen, P.A., Becker, L.B., 2006. Effects of compression depth and pre-shock pauses predict defibrillation failure during cardiac arrest. Resuscitation 71, 137–145. https://doi.org/10.1016/j.resuscitation.2006.04.008
Edelson, D.P., Robertson-Dick, B.J., Yuen, T.C., Eilevstjønn, J., Walsh, D., Bareis, C.J., Vanden Hoek, T.L., Abella, B.S., 2010. Safety and efficacy of defibrillator charging during ongoing chest compressions: A multi-center study. Resuscitation 81, 1521–1526. https://doi.org/10.1016/j.resuscitation.2010.07.014
Hansen, L.K., Folkestad, L., Brabrand, M., 2013. Defibrillator charging before rhythm analysis significantly reduces hands-off time during resuscitation: a simulation study. Am J Emerg Med 31, 395–400. https://doi.org/10.1016/j.ajem.2012.08.029
Hunziker, S., Tschan, F., Semmer, N.K., Zobrist, R., Spychiger, M., Breuer, M., Hunziker, P.R., Marsch, S.C., 2009. Hands-on time during cardiopulmonary resuscitation is affected by the process of teambuilding: a prospective randomised simulator-based trial. BMC Emergency Medicine 9, 3. https://doi.org/10.1186/1471-2... B.N., Alstrup K., Faurby R., Christensen S., Kirkegaard H., 2019. Introducing pre-charge in the pre-hospital setting: A feasibility study. Acta Anaesthesiologica Scandinavica 63.
Kemper, M., Zech, A., Lazarovici, M., Zwissler, B., Prückner, S., Meyer, O., 2019. Defibrillator charging before rhythm analysis causes peri-shock pauses exceeding guideline recommended maximum 5 s. Anaesthesist 68, 546–554. https://doi.org/10.1007/s00101... Hansen, L., Mohammed, A., Pedersen, M., Folkestad, L., Brodersen, J., Hey, T., Lyhne Christensen, N., Carter-Storch, R., Bendix, K., Hansen, M.R., Brabrand, M., 2016. The Stop-Only-While-Shocking algorithm reduces hands-off time by 17% during cardiopulmonary resuscitation - a simulation study. Eur J Emerg Med 23, 413–417. https://doi.org/10.1097/MEJ.00... J., Hawkins E., Vandeventer S., 2012. The impact of an educational intervention on the pre-shock pause interval among patients experiencing an out-of-hospital cardiac arrest. Academic Emergency Medicine 19.
Thim, T., Grove, E.L., Løfgren, B., 2012. Charging the defibrillator before rhythm check reduces hands-off time during CPR: A randomised simulation study. Resuscitation 83, e210–e211. https://doi.org/10.1016/j.resuscitation.2012.07.034