Elsevier

Resuscitation

Volume 73, Issue 1, April 2007, Pages 109-114
Resuscitation

Manikin and simulation studies
The impact of manual defibrillation technique on no-flow time during simulated cardiopulmonary resuscitation

https://doi.org/10.1016/j.resuscitation.2006.08.009Get rights and content

Summary

Introduction

Rapid defibrillation is the most effective strategy for establishing return of spontaneous circulation following cardiac arrest due to ventricular fibrillation. The aim of this study is to measure the delay due to of charging the defibrillator during chest compression in an attempt to reduce the duration of the pre-shock pause in between cessation of chest compressions and shock delivery as advocated by the American Heart Association (AHA) guidelines compared to charging the defibrillator immediately following rhythm analysis without resuming chest compressions as recommended by the European Resuscitation Council (ERC).

Methods

This was a randomised controlled cross over trial comparing pre-shock pause times when defibrillation was performed on a manikin according to the AHA and ERC guidelines using paddles and hands free defibrillation systems.

Results

The pre-shock pause between cessation of chest compression and shock delivery was significantly different between techniques (Friedman test, P < 0.0001). ERC paddles technique had the greatest pre-shock pause (7.4 s [6.7–11.2]) followed by ERC hands free (7.0 s [6.5–8.5]) and AHA paddles (1.6 s [1.1–2.3]). AHA hands free took the least amount of time (1.5 s [0.8–1.5]). Extrapolating these data to older defibrillators with longer charge times saw pre-shock pause intervals of 9 s (Codemaster XL) and 12 s (Lifepak 20) with the ERC approach.

Conclusion

This study demonstrated clinically significant delays to defibrillation by analysing and charging the defibrillator without performing concurrent chest compressions. In a simulated scenario, charging the defibrillator whilst performing chest compressions was perceived as safe and significantly reduced the pre-shock pause between cessation of chest compression and shock delivery.

Introduction

Defibrillation provides the most effective strategy for establishing return of spontaneous circulation (ROSC) following cardiac arrest due to ventricular fibrillation (VF).1 Chest compressions achieve at best a cardiac output approximately 30% of the spontaneously beating heart. Interruptions in chest compressions are known to reduce cardiac output, coronary and cerebral perfusion pressures.2 Several studies have shown that even short pauses in CPR before defibrillation reduce the rate of survival and good neurological outcome significantly in animal models of cardiac arrest.3, 4, 5 More recently, Eftestol et al. reported a 50% relative reduction in the probability of ROSC in humans in cardiac arrest due to VF when defibrillation was delayed for more than 5 s after cessation of chest compressions.6

Several steps are involved in the process of preparing to defibrillate and delivering a shock. These include establishing cardiac monitoring, analysing the underlying cardiac rhythm, placing gel pads/paddles or adhesive electrodes on the chest, charging the defibrillator capacitor, ensuring electrical safety and discharging the shock. These steps increase “hands off” time between cessation of chest compression and shock delivery (defined as the pre-shock pause). We have demonstrated previously that different approaches to establishing cardiac monitoring and defibrillation using manual defibrillators influence the time taken to deliver a shock.7 The use of automated external defibrillators further increases the “hands off” time associated with defibrillation and has been cited as a reason for them failing to achieve their full potential.5

The importance of minimising the pre-shock pause duration was highlighted in the 2005 International Consensus on Science and Treatment Recommendations conference.1 Following this, the European Resuscitation Council (ERC) and American Heart Association (AHA) developed local guidelines for implementation of the International Consensus on Science and Treatment Recommendations into clinical practice. Although similar advanced life support treatment algorithms were developed by both organisations, the recommended strategy for delivering a shock contained certain differences. The ERC recommend: apply pads or self adhesive pads to the chest; stop compressions, diagnose the underlying heart rhythm; if a shockable rhythm is identified, charge the defibrillator, warn team to stand clear and deliver a shock. Immediately after the shock is delivered, recommence chest compression.8 In contrast, the AHA advised: apply pads or self adhesive pads to the chest; stop compressions; analyse the heart rhythm; restart compressions; if a shock is indicated, charge the defibrillator, warn team to stand clear; stop compressions and deliver the shock. Immediately after the shock, chest compressions are again recommenced.9 The impact of these different approaches to defibrillation on the pre-shock pause duration has not been investigated previously.

The aim of this study was to investigate the delay due to of the ERC and AHA defibrillation strategies on the duration of the pre-shock pause between cessation of chest compression and shock delivery.

Section snippets

Study design

The study was a randomised controlled cross over study. Physicians, nurses and paramedical volunteers who were qualified Resuscitation Council (UK) ALS instructors or ALS providers10 were recruited. The study took place during June 2006 at Birmingham Heartlands Hospital, UK. The participants were given a short introductory talk in pairs describing the ERC and AHA defibrillation strategies and were then allowed to practise the techniques (using paddles and hands free adhesive pads) until they

Results

Twenty-two participants took part in the study. Complete data sets were collected for all participants. Thirteen participants were ALS instructors (nine male; mean age 39.5 (S.D. 5.5) years, five physicians, seven nurses; one operating department practitioner). The remaining nine participants were ALS providers (six male; mean age 30.1 (S.D. 3.6) years, seven physicians, two nurses).

Discussion

The main finding of this study is that defibrillation technique significantly influences the pre-shock pause between cessation of chest compressions and shock delivery. Using a modern defibrillator and the AHA approach of charging during defibrillation the pre-shock pause time was less than 2 s compared to times in excess of 7 s using the ERC approach of charging with hands off the chest. Extrapolating these findings to older defibrillators with longer charge times saw hands off intervals of 9 s

Conclusion

This simulation study demonstrated clinically significant delays to defibrillation by analysing and charging the defibrillator without performing concurrent chest compressions. In this study, charging the defibrillator whilst performing chest compressions was perceived as safe and reduced the pre-shock pause duration associated with defibrillation significantly.

References (17)

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Cited by (49)

  • A prospective evaluation of the ‘C.O.A.C.H.E.D.’ cognitive aid for emergency defibrillation

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    In particular, high-quality chest compressions are considered to be pertinent.5 The need for high-quality chest compressions is supported by various observational and physiological studies of cardiac arrest.6,7 Defibrillation guidelines recommend charging the defibrillator prior to pausing chest compressions.8

  • European Resuscitation Council Guidelines for Resuscitation 2015. Section 3. Adult advanced life support.

    2015, Resuscitation
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    The delay between stopping chest compressions and delivery of the shock (the pre-shock pause) must be kept to an absolute minimum; even 5–10 s delay will reduce the chances of the shock being successful.328–331,424,425 The pre-shock pause can be reduced to less than 5 s by continuing compressions during charging of the defibrillator and by having an efficient team coordinated by a leader who communicates effectively.297,426 The safety check to avoid rescuer contact with the patient at the moment of defibrillation should be undertaken rapidly but efficiently.

  • Feasibility of automated rhythm assessment in chest compression pauses during cardiopulmonary resuscitation

    2013, Resuscitation
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    Over the years, AED operation has been modified to minimise pre-shock pauses. Charging the capacitor during ongoing chest compressions could save 5–12 s.9,10 Simplified voice prompts and full pre-charge during rhythm assessment can shorten pauses by 11 s.11 Rhythm assessment during chest compressions followed by a short 4 s pause for rhythm verification and charging could reduce 14 s.31 Triggering rhythm assessment following the automatic detection of the end of chest compressions may spare 5.8 s.12 Despite all these improvements a pause to analyse the rhythm is still necessary. With our proposal this pause is eliminated because, once a shock has been advised during a ventilation pause, the rescuer can continue chest compressions until immediately before the shock.

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A Spanish translated version of the summary of this article appears as Appendix in the final online version at 10.1016/j.resuscitation.2006.08.009.

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