Clinical paperPauses in chest compression and inappropriate shocks: A comparison of manual and semi-automatic defibrillation attempts☆
Introduction
The development of automated external defibrillators (AEDs) has made defibrillation more readily available for patients in cardiac arrest. A number of studies have confirmed the safety and effectiveness of AEDs, and the importance of early defibrillation,1 but population-based investigations from Seattle and Sweden have shown at best a moderate increase in survival over the years despite a decreased time to defibrillation.2, 3
Studies have shown that the probability of successful defibrillation and subsequent return of spontaneous circulation (ROSC) deteriorates rapidly with even short pauses in chest compressions.4, 5 The use of AEDs requires time without chest compressions during rhythm analysis and charging, in addition to any further human delays.6 In many systems, medical personnel trained in advanced life support (ALS) are therefore encouraged to use defibrillators in manual mode to shorten time used for analysis, but the ability to recognise different ECG-patterns may be more difficult during a stressful clinical situation than during manikin simulation.
We have recently reported on CPR quality in three ambulance services (London, Stockholm, and Akershus)7, 8 and one university hospital (Chicago)9 using defibrillators modified to enable continuous monitoring of ventilation and chest compression depth and rate. The defibrillators were used in manual mode (Akershus and Chicago), or in AED mode (London and Stockholm). In this pre-planned analysis we hypothesised that manual use of the defibrillator would result in shorter pauses between chest compression and subsequent shock (pre-shock pause), between shocks (inter-shock pause), and from last shock in a series to the resumption of chest compressions (post-shock pause), but more frequent shocks for non-VF/VT rhythms (i.e., inappropriate shocks).
Section snippets
Materials and methods
Methods, especially regarding CPR-sensing technology and subject enrolment, have been presented in detail previously.7, 8, 9 The present description of study methods highlights concepts particular to this analysis of defibrillation and compression pauses.
Discussion
In this prospective study peri-shock intervals without chest compressions were shorter with defibrillators in manual mode than in AED mode, but more inappropriate shocks were given in manual mode.
Such intervals without chest compressions have only been studied previously during the use of AEDs,16, 17, 18, 19 and the present findings in the AED group are similar to previous findings. Sunde et al found median 20 s pre-shock pauses for ambulance personnel using Heartstart 3000 defibrillators
Conclusion
Manual defibrillation attempts resulted in less time without chest compressions than AED use of identical defibrillators, but a higher proportion of inappropriate shocks. A higher formal level of education did not prevent inappropriate shocks.
Conflict of interest statements
All authors have received funding and technical support for research projects regarding quality of CPR from Laerdal Medical and Philips Medical Systems. Drs. Abella, Becker, and Edelson have received honoraria from Laerdal Medical and/or Philips Medical Systems. Dr. Wik is on a medical advisory board for Medtronic Medical. Dr. Steen is a board member of Laerdal Medical and The Norwegian Air Ambulance Foundation.
Acknowledgements
The authors wish to thank all participating EMTs, paramedics, nurses, and physicians for their invaluable effort in obtaining and collecting the data. The helpfulness and technical skills of Ståle Freyer, MSc (Unversity of Stavanger, Norway), Salem Kim, Helge Myklebust and all the staff at Laerdal Medical, Research and Development, Stavanger, Norway are most appreciated.
Funding. Funding for this project was received from The Norwegian Air Ambulance Foundation (Kramer-Johansen, full time PhD
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2017, Journal of Emergency MedicineMinimizing pre- and post-shock pauses during the use of an automatic external defibrillator by two different voice prompt protocols. A randomized controlled trial of a bundle of measures
2016, ResuscitationCitation Excerpt :According to the Guidelines 2000 for emergency cardiac care, automated external defibrillators (AEDs) should prompt for pauses in cardiopulmonary resuscitation (CPR) for rhythm analysis, shock delivery and pulse checks similar to procedures for manual defibrillators.1,2 These pauses however limit the delivery of chest compressions to less than 50% of the time spent in the resuscitation attempt.3–6 To decrease hands-off time, Guidelines 20057,8 eliminated post-shock pauses for rhythm analysis and pulse checks.
Mechanical chest compressions improved aspects of CPR in the LINC trial
2015, ResuscitationRhythm analysis and charging during chest compressions reduces compression pause time
2015, ResuscitationCitation Excerpt :ALS providers often operate the defibrillator in manual mode when treating cardiac arrest patients. Manual rhythm analyses can generally be conducted more quickly than automated analyses, however, manual analyses are less accurate.18,19 Specifically, in one investigation, pre-shock pause was 7 s shorter with manual vs. AED analyses; however 26% of shocks were inappropriate following manual analyses compared with 6% following AED analyses.18
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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.2006.09.006.