Clinical paperLocal lay rescuers with AEDs, alerted by text messages, contribute to early defibrillation in a Dutch out-of-hospital cardiac arrest dispatch system☆
Introduction
Early defibrillation may be the most important determinant of survival of out-of-hospital cardiac arrest (OHCA). Time to first shock provided by an emergency medical service (EMS) defibrillator is eleven to twelve minutes, resulting in low survival.1, 2 To decrease this delay, public access defibrillation programs with on-site automated external defibrillators (AEDs) have been implemented, directed at densely populated and high-risk sites.3, 4, 5, 6, 7 These AEDs can be used by people who are in close proximity of the cardiac arrest and can most effectively decrease time to first shock and thereby increase survival.1, 4 In some countries (e.g. the Netherlands), first responders (e.g. policemen) with AEDs are also dispatched to a suspected cardiac arrest as part of an organized EMS response. They are dispatched to both public and non-public sites, but can decrease time to first shock much less than on-site AEDs. Consequently, they are not able to increase survival to the extent that can be achieved by on-site AED use.2, 8, 9
About three-quarters of all cardiac arrests occur in non-public places, like residential areas, where on-site AEDs are rarely available.2, 6, 7, 10, 11 Patients in non-public places are therefore primarily assisted by dispatched first responders and EMS. To benefit optimally from AEDs, residential areas are in need of another type of responder. Such a responder needs to be closer to the cardiac arrest patient than first responders and/or EMS, and must be alerted to take action.
The Dutch Heart Foundation has set a target for action to achieve early defibrillation. It has formulated the concept of “6-minute zones”: regions where the emergency response is organized to achieve defibrillation for OHCA within 6 min after emergency call, irrespective of the patients’ location. A text message (TM)-alert system, which focuses on OHCAs in residential areas, has therefore been implemented by regional dispatch centers. This system alerts local lay rescuers to perform CPR or directs them to a nearby AED first. In this study we analyzed the functioning of this system with the focus on response times and early defibrillation in relation to other dispatched and on-site responders.
Section snippets
Settings
In the Netherlands, when a cardiac arrest is suspected, the dispatcher sends two ambulances from a single tier equipped with a defibrillator and first responders (e.g. policemen) with an AED. These first responders are dispatched as part of the organized response but are considered lay rescuers; their training includes the standard ERC basic life support (BLS)/AED course for lay rescuers and they only perform tasks according to this course.
The current study is part of the AmsteRdam
Results
During the 42-month study period, EMS personnel attempted to resuscitate 1693 OHCA patients in the TM-alert system area, 1536 of whom were not witnessed by EMS (Fig. 2). The dispatcher activated the system in 893 of these 1536 (58.1%) cardiac arrests. Table 1 shows the characteristics of cases where the dispatcher decided to activate or to not to activate the system. While non-cardiac causes were more prevalent in non-TM-activated cases, the great majority still had a cardiac cause (84.4%
Discussion
This study describes a novel centrally controlled system where text messages are used to jointly activate TM-responders with and without directions to nearby AEDs. Our results suggest that TM-responders with AEDs contribute to a shortening of time to defibrillation compared to EMS. In 12.0% of all OHCAs, they were the first to connect an AED. In 12.3% they were responsible for early connection (≤6 min) and in 7.3% of cases for early defibrillation (≤6 min).
The contribution of TM-responders is
Limitations
We have no insight in the exact location of TM-responders at the time of the alert, nor in the number of cases in which a TM-responder responded and started CPR. In an earlier study from 2009 to 2010 of alerted TM-responders, approximately 28% responded.20 Further developments of mobile phone technology may make this information available and can make the TM-system dispatch more efficient.
Conclusions
A mobile phone text message system that included both local lay rescuers and nearby AEDs, contributes to earlier defibrillation in OHCA patients. It addresses a need for early defibrillation in residential areas where the majority of cardiac arrests occur and where public access AEDs usually do not contribute. Its contribution to improved survival needs to be determined with further studies.
Conflict of interest statement
Data collection for this study was made possible by unconditional grants from ZonMW (#82711001), Physio Control Inc. (Redmond, WA, USA), Zoll Medical (Chelmsford, MA, USA), Defibtech (Guilford, CONN, USA), and Cardiac Science (Waukesha, WI, USA), the provinces of North-Holland and Overijssel. JAZ and RS are supported by a grant from the Dutch Heart Foundation (#2010T083). The funders had no access to the data and did not contribute to the preparation of this manuscript.
Acknowledgements
We thank Loes Bekkers and Paulien Homma for expert data management. We are grateful for all participating dispatch centers, EMS, first responders, TM-responders, as well as HartslagNu for their cooperation and support. Special thanks to Irmgard Maassen, Jeanet Glas, Gerard Kamphuis, Ron Regoort, and medical students who helped to collect the data of used AEDs.
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A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2014.07.020.
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Both authors contributed equally to this work.