Should Every School and Workplace Have an AED?
Out-of-hospital cardiac arrest (OHCA) is a leading cause of death in the industrialized world. The global average incidence is 55 adult OHCAs of presumed cardiac cause per 100,000 person-years, of whom on average 7% will be discharged alive from the hospital.(1) Many OHCAs are precipitated by lethal heart arrhythmias (ventricular fibrillation or pulseless ventricular tachycardia) that can be reversed only by the shock with a defibrillator. The sooner the shock is delivered, the higher the probability the victim will survive the event. Without treatment, the chance of survival from OHCA decreases by 7% to 10% for every minute of delay.(2) To improve survival after an OHCA, early defibrillation by laypersons using an automated external defibrillator (AED) play a key role in the “chain of survival”.(3)
Previous recommendations of the American Heart Association and International Liaison Committee on Resuscitation support the idea that defibrillators should be widely available and accessible.(4,5) This raises the question whether all schools(6) and workplaces should have AEDs.
AEDs are designed for use by non-medical personnel so that defibrillation can be delivered before emergency medical services (EMS) personnel arrive at the scene. There are two ways of making an AED available to cardiac arrest victims. First, AEDs can be placed at a specific location like the school or workplace (onsite AED). In this setting, the AED will only be used on patients who suffer their cardiac arrest at the site of the AED. Second, EMS services may dispatch first responders like fire fighters or policemen with an AED to the scene of the cardiac arrest (dispatched AED programs). In this setting, the AED can cover a much larger area and thus serves a broader public.
Small studies conducted around the introduction of AEDs in specific study locations like casinos(7) and airports(8) have shown high survival rates for patients with a shockable initial rhythm, ranging from 53% to 61%.
The outcomes of dispatched AED studies were not all equally promising. Although observational studies showed dispatched AED use tripled survival rates in comparison to historical controls,(9,10) a randomized controlled clinical trial with initial random allocation of AEDs to first responders showed no significant survival benefit. (11) Until recently, clinical data from a ‘real world’ setting showing the survival benefit of onsite and dispatched AED use have been lacking.
A recent Dutch observational cohort study showed the effectiveness of the AED is mainly determined by the time interval between the collapse of the patient and the first shock given.(12) Onsite AED use significantly reduced the time to first shock from 11 minutes to 4.1 minutes. Survival with minimal neurologic impairment was 49.6% for patients treated with an onsite AED against 14.3% for those without AED treatment. Dispatched AED use only showed a marginal survival benefit due to a limited reduction in time to shock (11 to 8.5 minutes), observed at the end of the survival window. However, both onsite AEDs and dispatched AED programs have proven to effectively increase survival rates in public locations (adjusted odds ratio 3.40; 95% CI, 2.12-5.44 and 1.88; 95%CI, 1.18-3.00, respectively).
Optimal Placement of AEDs
Public-access defibrillation programs require strategic placement of defibrillators where the risk of cardiac arrest is high. The AHA proposes AED placement in areas with at least 1 cardiac arrest every 5 years.(13) A recent Danish study showed that if public-access defibrillation programs are to improve survival in the community, the AEDs must cover the greatest possible number of cardiac arrests occurring in public.(14) A cardiac arrest was ≈5 to 8 times more likely to occur at train stations, ferry terminals, or high-density public areas than areas without such characteristics, like schools or large industrial businesses. These findings emphasize that parameters such as the number and characteristics of visitors (with the same lower limit of more than 250 people over the age of 50 present for more than 16 hours a day) also need to be taken into account for optimal placement of AEDs.(15)
To place an AED at every school is debatable, since the age group of students is associated with a relatively low risk of OHCA. In schools in Seattle and King County, WA,(16) cardiac arrest occurred on average in ≈1 of 111 schools annually, with a greater incidence among colleges (1 OHCA per 8 colleges) than among high schools (1 per 125 high schools) or lower-level schools (1 OHCA per 200 preschools through middle schools). Only 12% of the OHCAs were among students; the majority of cases were among faculty and staff (34%), and among adults not employed by the school (46%).
Placing defibrillators in the workplace is just as controversial, because cardiac arrest rarely occurs in this setting. Depending on the definition of “workplace”, the reported proportion of OHCAs occurring in that setting was 1-6%.(12, 17-24) Despite its relatively low incidence, several authors have reported that patients who experience OHCA in the workplace have a relatively high survival rate.(15,16) The Resuscitation Outcome Consortium showed that survival after OHCA in a workplace increased even more (from 15% to 22%) if an AED had been used.(22) These impressive survival rates have been attributed to a high percentage of bystander witnessed collapse and CPR.(21) Effective CPR slows down deterioration of ventricular fibrillation,(23) prolonging the window of opportunity for successful defibrillation.(24)
If money were no object, every school and workplace should have one or more AEDs, depending on the size of the premises. The closer the AED is located to the potential victim, the shorter the time to shock, and the higher the chances of survival. Because an OHCA is relatively rare in the workplace and school, defibrillators might not be cost effective in these settings. Aside from the purchase of the AED(s), the device(s) need to be maintained, and potential lay rescuers need to be trained in basic life support techniques and AED use on a regular base. These issues need to be implemented in a coordinated and practiced emergency response plan.(25) This plan must start with development of a good system of communication, and requires development and coordination of a planned and practiced response, and risk reduction.
The findings of the recent Dutch study(12) should encourage communities worldwide to explore which AED program is optimal for their situation, taking into account the incidence and risk factors of cardiac arrest at the location, financial means and the time it takes emergency teams to arrive at the scene.
- Berdowski J, Berg RA, Tijssen JG, Koster RW. Global incidences of out-of-hospital cardiac arrest and survival rates: Systematic review of 67 prospective studies. Resuscitation. 2010;81:1479-1487.
- Larsen MP, Eisenberg MS, Cummins RO, Hallstrom AP. Predicting survival from out-of-hospital cardiac arrest: a graphic model. Ann Emerg Med. 1993;22:1652–1658.
- Cummings RO, Ornate JP, This WH, Pepe PE. Improving survival from sudden cardiac arrest: the “chain of survival” concept: a statement for health professionals from the Advanced Cardiac Life Support Committee, American Heart Association. Circulation. 1991;83:1832–1847.
- Weisfeldt ML, Kerber RE, McGoldrick RP, Moss AJ, Nichol G, Ornato JP, Palmer DG, Riegel B, Smith SC Jr. Public access defibrillation. A statement for healthcare professionals from the American Heart Association Task Force on Automatic External Defibrillation. Circulation. 1995;92:2763.
- Kloeck W, Cummins RO, Chamberlain D, et al. ILCOR Advisory Statement: Early defibrillation: an Advisory Statement from the Advanced Life Support Working Group of the International Liaison Committee on Resuscitation. Circulation. 1997;95:2183–2184.
- Garza M. An AED in every school: the next step for public access defibrillation. J Emerg Med Serv. 2003;28:22–23.
- Valenzuela TD, Roe DJ, Nichol G, Clark LL, Spaite DW, Hardman RG. Outcomes of rapid defibrillation by security officers after cardiac arrest in casinos. N Engl J Med. 2000;343:1206–1209.
- Caffrey SL, Willoughby PJ, Pepe PE, Becker LB. Public use of automated external defibrillators. N Engl J Med. 2002;347:1242–1247.
- Myerburg RJ, Fenster J, Velez M, Rosenberg D, Lai S, Kurlansky P, Newton S, Knox M, Castellanos A. Impact of community-wide police car deployment of automated external defibrillators on survival from out-of-hospital cardiac arrest. Circulation. 2002; 106:1058-1064.
- Capucci A, Aschieri D, Piepoli MF, Bardy GH, Iconomu E, Arvedi M. Tripling survival from sudden cardiac arrest via early defibrillation without traditional education in cardiopulmonary resuscitation. Circulation. 2002; 106:1065-1070.
- van Alem AP, Vrenken RH, de Vos R, Tijssen JG, Koster RW. Use of automated external defibrillator by first responders in out of hospital cardiac arrest: prospective controlled trial. BMJ. 2003; 327:1312.
- Berdowski J, Blom MT, Bardai A, Tan HL, Tijssen JG, Koster RW. Impact of Onsite or Dispatched Automated External Defibrillator Use on Survival After Out-of-Hospital Cardiac Arrest. Circulation. 2011 Oct 17.
- Aufderheide T, Hazinski MF, Nichol G, Steffens SS, Buroker A, McCune R, Stapleton E, Nadkarni V, Potts J, Ramirez RR, Eigel B, Epstein A, Sayre M, Halperin H, Cummins RO. Community lay rescuer automated external defibrillation programs: key state legislative components and implementation strategies: a summary of a decade of experience for healthcare providers, policymakers, legislators, employers, and community leaders from the American Heart Association Emergency Cardiovascular Care Committee, Council on Clinical Cardiology, and Office of State Advocacy. Circulation. 2006;113:1260–1270.
- Folke F, Lippert FK, Nielsen SL, Gislason GH, Hansen ML, Schramm TK, Sørensen R, Fosbøl EL, Andersen SS, Rasmussen S, Køber L, Torp-Pedersen C. Location of cardiac arrest in a city center: strategic placement of automated external defibrillators in public locations. Circulation. 2009;120:510-517.
- Ornato JP, McBurnie MA, Nichol G, Salive M, Weisfeldt M, Riegel B, Christenson J, Terndrup T, Daya M; PAD Trial Investigators. The Public Access Defibrillation (PAD) trial: study design and rationale. Resuscitation. 2003;56:135-147.
- Lotfi K, White L, Rea T, Cobb L, Copass M, Yin L, Becker L, Eisenberg M. Cardiac arrest in schools. Circulation. 2007;116:1374-1379.
- Engdahl J, Herlitz J. Localization of out-of -hospital cardiac arrest in Goteborg 1994-2002 and implications for public access defibrillation. Resuscitation. 2005;64:171-175.
- Descatha A, Frederic M, Devere C, Dolveck F, Goddet S, Baer M, Chauvin M, Fletcher D, Templier F. Details of the initial management of cardiac arrest occurring in the workplace in a French urban area. Resuscitation. 2005;65:301-7.
- Becker L, Eisenberg M, Fahrenbruch C, Cobb L. Public locations of cardiac arrest. Implications for public access defibrillation. Circulation. 1998;97:2106-9.
- Reed DB, Birnbaum A, Brown LH, O'Connor RE, Fleg JL, Peberdy MA, Van Ottingham L, Hallstrom AP; PAD Trial Investigators. Location of cardiac arrests in the public access defibrillation trial. Prehosp Emerg Care. 2006;10:61-76.
- Muraoka H, Ohishi Y, Hazui H, Negoro N, Murai M, Kawakami M, Nishihara I, Fukumoto H, Morita H, Hanafusa T. Location of out-of-hospital cardiac arrests in Takatsuki city: where should automated external defibrillator be placed? Circ J. 2006;70:827-31.
- Weisfeldt ML, Sitlani CM, Ornato JP, Rea T, Aufderheide TP, Davis D, Dreyer J, Hess EP, Jui J, Maloney J, Sopko G, Powell J, Nichol G, Morrison LJ; ROC Investigators. Survival after application of automatic external defibrillators before arrival of the emergency medical system: evaluation in the Resuscitation Outcomes Consortium population of 21 million. J Am Coll Cardiol. 2010;55:1713–1720.
- Waalewijn RA, Nijpels MA, Tijssen JG, Koster RW. Prevention of deterioration of ventricular fibrillation by basic life support during out-of-hospital cardiac arrest. Resuscitation. 2002;54:31-36.
- Valenzuela TD, Roe DJ, Cretin S, Spaite DW, Larsen MP. Estimating effectiveness of cardiac arrest interventions: a logistic regression survival model. Circulation. 1997;96:3308–3313.
- Hazinski MF, Markenson D, Neish S, Gerardi M, Hootman J, Nichol G, Taras H, Hickey R, OConnor R, Potts J, van der Jagt E, Berger S, Schexnayder S, Garson A Jr, Doherty A, Smith S; American Heart Association; American Academy of Pediatrics; American College of Emergency Physicians; American National Red Cross; National Association of School Nurses; National Association of State EMS Directors; National Association of EMS Physicians; National Association of Emergency Medical Technicians; Program for School Preparedness and Planning; National Center for Disaster Preparedness; Columbia University Mailman School of Public Health. Response to cardiac arrest and selected life-threatening medical emergencies: the medical emergency response plan for schools: A statement for healthcare providers, policymakers, school administrators, and community leaders. Circulation. 2004;109:278-291.
Keywords: Arrhythmias, Cardiac, Defibrillators, Electric Countershock, Out-of-Hospital Cardiac Arrest, Probability, Tachycardia, Ventricular, Ventricular Fibrillation
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