In a cardiac arrest, timely intervention is crucial. In an Out of Hospital Cardiac Arrest (OHCA), survival rates correlate directly to the speed at which appropriate intervention is delivered[i], and the average survival rates (to discharge from hospital) are, accounting for the many variables in a cardiac arrest, less than 10%[ii]. Initiatives like Take Heart America which aim to increase bystander CPR rates through training and provision of publicly accessible Automated External Defibrillators (AEDs) have shown compelling results in survival rates after OHCA[iii].
Early, high-quality chest compressions are key in ensuring blood supply to essential organs, crucially maintaining perfusion of the brain and reducing the risk and impact of hypoxic brain injury post-arrest. While chest compressions can buy time, the chances of return of spontaneous circulation (ROSC) without defibrillation can be as low as 5%, compared to at least 25% in OHCAs with prompt response and access to a cardiac defibrillator. A recent study by the American Heart Association found that the median average for survival from a cardiac arrest with near-immediate bystander CPR and use of a public access defibrillator was around 40%[iv]. Furthermore, some studies show that, for those patients who received early defibrillation in the community and were discharged from hospital without significant impairment, the long-term prognosis is similar to that of the general population[v].
The availability of accessible AEDs is essential for the delivery of high standard timely resuscitation efforts. AEDs can be used safely even by untrained bystanders, and efforts should be made to raise public awareness that AEDs are designed for people who haven’t had training.
There has been varied uptake of AEDs in community settings, with reasons such as initial cost, upkeep, and businesses or centers being unable or unwilling to provide staff with a comprehensive and cost-effective training program. The initial cost of the devices and cost of maintenance are clearly issues that need to be addressed with individuals, and local fundraising or philanthropic initiatives for covering the costs of community AEDs have met with some success. Life-saving healthcare will always be at the forefront of research and development and emergent technologies are set to make public access defibrillators more affordable and user-friendly than ever.
As time is critical in an OHCA, the geographical availability of AEDs must be considered; emphasis must be placed on areas with highest potential problems associated with OHCAs[vi], which can be broadly grouped into three categories:
Those with sheer high volume of people, such as shopping malls or airports; these have the advantage of potential funding from the enterprise itself, or businesses and individuals located at the venue.
Those with a higher than average burden of unwell or vulnerable people, for example, non-emergency medical centers or community centers catering to the elderly or groups with special health needs.
Those where emergency services are unlikely to be able to provide early interventions, such as remote or island communities or offshore working environments.
In addition, provision should be considered for places where, although the likelihood of OHCA is not higher than average, the event of death from a potentially treatable cardiac arrest would be devastating, such as schools. AEDs should be placed in such a way that they can be reached within a few minutes of determining need, and well signposted[vii]. This means that very large sites need to have several AEDs, spaced at appropriate intervals and with the locus of demand considered.
The placement of AEDs should be chosen with a particular view to accessibility round the clock, i.e. a 24/7 grocery store or gas station is preferable to a venue which is only open normal office hours. Or, better, both locations should consider AED placement. In practice, opening hours of some AED venues account for an average coverage loss of around 20%[viii]. Where they can’t be placed in safe accessible venues, AEDs can be kept in cabinets anywhere, for access anytime. There’s been much debate about whether or not these should be locked with a keycode – attainable by calling emergency services or a specific helpline – or unlocked, perhaps with an alarm to deter vandalism. A UK-wide initiative installing several thousand AEDs in busy public areas found the incidence of vandalism almost negligible, and the risks from improperly handling an AED non-existent, and concluded that the opportunity for early life saving intervention is worth the risk of leaving unsecured equipment[ix].
The benefits of easy-to-use, rapidly accessible defibrillators cannot be overstated, and it is very difficult to find an argument against massive deployment of these intrinsically safe, life-saving devices.
An effective educational program for basic and immediate life support is also key, and as information is disseminated both through approved training programs and mass or social media campaigns, rates of bystander intervention at OHCAs is increasing[x]. Additionally, with the development of modern devices with comprehensive voice-prompts and foolproof instructions at the scene, reliance on implementation of training programs is less crucial – though obviously very desirable.
As deployment and uptake of AEDs increases, a new generation of public access defibrillators is set to come into widespread use; more cost-effective devices mean that optimum placement for timely intervention can be fully achieved. The future of OHCA will be revolutionized with simple, safe devices available within an easy distance of nearly all homes, schools, and workplaces.
[i] Ian Jacobs, Vinay Nadkarni and the ILCOR Task Force on Cardiac Arrest and Cardiopulmonary Resuscitation Outcomes et al Cardiac Arrest and Cardiopulmonary Resuscitation Outcome Reports 2004 https://doi.org/10.1161/01.CIR.0000147236.85306.15
[ii] Jan-Thorsten Grasner, the German Resuscitation Registry Study Group et al, ROSC after cardiac arrest—the RACA score to predict outcome after out-of-hospital cardiac arrest European Heart Journal (2011) 32, 1649–1656 doi:10.1093/eurheartj/ehr107
[iii] Lick, Charles J. MD; Aufderheide, Tom P. MD; Niskanen, Robert A. MSEE; Steinkamp, Janet E. MA; Davis, Scott P. MD, FCCM; Nygaard, Susan D. RN; Bemenderfer, Kim K. NREMT-I; Gonzales, Louis EMT-P; Kalla, Jeffrey A. NREMT-P; Wald, Sarah K. BA; Gillquist, Debbie L. EMT-P; Sayre, Michael R. MD; Oski Holm, Susie Y. MPH; Oakes, Dana A. BS; Provo, Terry A. EMT-P; Racht, Ed M. MD; Olsen, John D. MD; Yannopoulos, Demetris MD; Lurie, Keith G. MD Take Heart America: A comprehensive, community-wide, systems-based approach to the treatment of cardiac arrest Critical Care Medicine: January 2011 – Volume 39 – Issue 1 – p 26-33
[iv] Bækgaard JS1, Viereck S2, Møller TP2, Ersbøll AK2, Lippert F2, Folke F2. The Effects of Public Access Defibrillation on Survival After Out-of-Hospital Cardiac Arrest: A Systematic Review of Observational Studies.
Circulation. 2017 Sep 5;136(10):954-965. doi: 10.1161/CIRCULATIONAHA.117.029067. Epub 2017 Jul 7.
[v] T. Jared Bunch, M.D., Roger D. White, M.D., Bernard J. Gersh, M.B., Ch.B., Ryan A. Meverden, B.S., David O. Hodge, M.S., Karla V. Ballman, Ph.D., Stephen C. Hammill, M.D., Win-Kuang Shen, M.D., Douglas L. Packer, M.D. Long-Term Outcomes of Out-of-Hospital Cardiac Arrest after Successful Early Defibrillation June 26, 2003 N Engl J Med 2003; 348:2626-2633 DOI: 10.1056/NEJMoa023053
[vi] Michael E. Field and Richard L. Page. The Right Place at the Right Time: Optimizing Automated External Defibrillator Placement in the Community https://doi.org/10.1161/CIRCULATIONAHA.117.027305 Circulation. 2017;135:1120–1122
[vii] Occupational Safety and Health Administration Saving Sudden Cardiac Arrest Victims in the Workplace: Automated External Defibrillators OSHA 3185-09N 2003
[viii] Sun CL, Demirtas D, Brooks SC, Morrison LJ, Chan TC. Overcoming Spatial and Temporal Barriers to Public Access Defibrillators Via Optimization.
J Am Coll Cardiol. 2016 Aug 23;68(8):836-45. doi: 10.1016/j.jacc.2016.03.609.
[ix] Perkins GD, Lockey AS, de Belder MA on behalf of the Community Resuscitation Group, et al
National initiatives to improve outcomes from out-of-hospital cardiac arrest in England
Emerg Med J 2016;33:448-451
[x] Linda L. Culley, Thomas D. Rea, John A. Murray, Barbara Welles, Carol E. Fahrenbruch, Michele Olsufka, Mickey S. Eisenberg and Michael K. Copass Public Access Defibrillation in Out-of-Hospital Cardiac Arrest: A Community-Based Study