the Short-Term and Long-Term Results?
A. CAPUCCI, D. ASCHIERI, G.Q. VILLANI
Public access to defibrillation means making automated external defibrilla- tors available in public and/or private places where large numbers of people gather or people who are at high risk of heart attacks live. The automated external defibrillator is a computerised medical device that can check a per- son’s heart rhythm. It can recognise a potentially lethal rhythm that requires a shock and it can advise the rescuer when a shock is needed. The automatic external defibrillator uses voice prompts, lights, and text messages to tell the rescuer the steps to take. The concept of public access defibrillation is based on deductive reasoning. Early defibrillation improves outcome from cardiac arrest due to ventricular defibrillation (VF) [1–4]. The increased availability of automatic external defibrillators should result in earlier defibrillation, leading to better outcome from cardiac arrest. This concept has not been still proved prospectively.
Public access defibrillation dates from 1986, when the first defibrillator for public use became available. However, the concept failed to gain support for several reasons, particularly the lack of acceptance by physicians. Such devices were available through prescription, but few were prescribed despite family acceptance being reasonable, particularly in high-risk families. Cost and reimbursement also slowed acceptance. Current enthusiasm for public access defibrillation has been spurred by recent breakthroughs in automatic external defibrillator technology. Portable defibrillators can be deployed in two ways in the community: (1) in the vehicles of emergency personnel, such as police officers, who are otherwise not equipped with advanced life-sup- port equipment or a defibrillator; or (2) in fixed locations, such as casinos,
Cardiology Department, Guglielmo da Saliceto Hospital, Piacenza, Italy
airports, health clubs, office buildings, shopping malls, or government offices. The ideal primary outcome would be 30-day survival with intact neu- rological function [5]. However, it may be impractical to use this as an out- come, because individual consent would be needed to examine patients and medical records. Because informed consent may be difficult to obtain after resuscitation from sudden cardiac arrest, information about functional out- comes will be missing for some patients. If this information is missing for a large number of patients or is preferentially missing for patients enrolled in one intervention arm or the other, then the results of the study may be biased. As an alternative, a primary outcome of 30-day survival could be sup- plemented by information about hospital discharge status.
Results of Public Access Defibrillation
An important report from Seattle, Washington, examined ‘public’ location in cardiac arrest [6]. These investigators again confirmed that most cardiac arrests occur in the home (76%); only 16% occur in public sites. The most common public location for cardiac arrest was Seattle Tacoma Airport, where seven cardiac arrests occurred each year. Penitentiaries were the second most common location. Shopping malls had an average of 0.7 arrests each year, and sporting arenas 0.4 each year during major events. Other, less frequent locations included hotels, government offices, schools, and churches.
The clinical situations in which the defibrillator has been shown to have the greatest efficacy to date are airports and casinos [7, 8]. These two settings are similar to each other in several ways. In both, large numbers of dedicated work- ers are present in a relatively small geographic area, and large numbers of peo- ple who could experience sudden cardiac arrest are in daily proximity to the defibrillator. In the studies conducted in these settings, 40% or more of individ- uals experiencing cardiac arrest survived; this is a far higher percentage than that typically achieved anywhere else outside of a hospital.
Results of defibrillator deployment and use in other situations may have less benefit. The Public Access Defibrillation (PAD) [9] trial was a multi-cen- tre study in which community-based training was employed in ‘high-risk’
settings. The settings included facilities with more than 250 persons aged over 50 years on site for most of the day, or sites where a cardiac arrest had occurred within the past 2 years. A total of 1260 facilities were included. The community sites were mostly recreation, shopping, and entertainment facili- ties. Sites were randomised to have rescuers trained in CPR alone or rescuers trained in CPR and defibrillator use. Approximately 20 000 lay volunteers were trained, representing almost 10 volunteers per available defibrillator.
The primary endpoint of the study was survival to hospital discharge. More
cardiac arrests occurred in the CPR–defibrillator locations (n = 129) than in the CPR alone locations (n = 103). Twenty-nine patients in the CPR- defibrillator group survived to hospital discharge, compared with only 15 in the CPR alone group (P = 0.042). The survival rate in the CPR–defibrillator group was 22.5%. The PAD study showed that fixed-location defibrillators were useful even though the survival benefit seen was far more modest than in previous smaller, uncontrolled studies.
Recently, findings from Culley et al. [10] suggested a greater benefit from the use of public access defibrillation. In an observational study performed in Seattle, Washington, 475 defibrillators were deployed under emergency medical service (EMS)-guided surveillance. The majority of the devices were placed in areas such as shopping malls, but use of a defibrillator by mobile police was also included. Over 1% of cardiac arrests were treated with a defibrillator (1.33%), and survival to hospital discharge was a remarkable 50%. However, preliminary results in Seattle are backed by the best emer- gency medical response system in the world and thus may be difficult to reproduce elsewhere.
Defibrillators as Part of a Mobile EMS System
Defibrillators have also been used as an adjunct to EMS response systems. In this approach, emergency workers such as police and fire workers are equipped with defibrillators in the absence of other advanced cardiac life- support equipment and are dispatched in parallel with ambulances to car- diac arrests. Two large trials have examined the efficacy of this approach [11, 12]. Myerburg et al. [11] established such a system in Dade County, Florida, comparing outcomes of patients treated with defibrillators against the out- comes of historical controls in a non-randomised study. They found that response times to defibrillation were decreased by the dual deployment sys- tem and that survival to hospital admission was more likely among patients treated with rapid defibrillation. Unfortunately, 61% of patients in the study presented with non-shockable rhy thms, and therefore, no significant improvement in survival to hospital discharge was demonstrated.
Results similar to those in the Myerburg study but less significant were obtained in a prospective randomised trial performed in the Netherlands [12]. A witnessed cardiac arrest occurred in 469 subjects who were then ran- domised to receive a routine EMS response or a dual dispatch system response that included a police-equipped defibrillator. Although survival to hospital admission was higher in the police defibrillator-equipped group, survival to hospital discharge was 15% in the control group and 18% in the police group, a difference that was not significant.
Based on data from these two studies, it appears that providing rescue workers with vehicle-equipped defibrillators improves response times but not long-term outcomes. The reason for this disappointing dichotomy is not yet completely clear. It may be that improvements in existing defibrillator algorithms or in post-arrest treatment will be needed before defibrillator use can demonstrate significant outcome improvement.
However, better results in respect of short- and long-term survival have been obtained in other studies. In our study, too, Piacenza Progetto Vita, police equipped with automatic external defibrillators and conventional EMS responders are simultaneously deployed to possible cardiac arrests [13].
Policemen and lay responders were trained to use automatic external defib- rillator on a brief defibrillation training course without CPR instruction.
While survival to hospital admission was higher in the EMS group, survival rate to hospital discharge was significantly higher in the lay volunteers group (43.7%) than in the EMS group (16.6%) (P < 0.01). Neurologically intact survival rate was also higher in PPV-treated than in EMS-treated patients.
These patients were long-term survivors (more than 1 year). Only two patients died within 1 year, from non-cardiac causes (ictus and pulmonary cancer). The only intervention with a public defibrillator positioned in a fixed place (main city square) was recorded after 5 years from the beginning of the project, and was successfully.
White et al. of the Mayo Clinic in Rochester, Minnesota, reported their findings on police-initiated defibrillation [14]. The Rochester police depart- ment were equipped with automatic external defibrillators, on the reasoning that the police often arrive first at an emergency, and some of these could include cardiac arrest. Forty-one of 108 patients having a cardiac arrest were first shocked by the police. Spontaneous circulation was restored without additional advance cardiac life support in 14 patients (34%). These patients were long-term survivors. Among patients in whom spontaneous circulation could not be restored before arrival of the paramedics and who needed fur- ther advanced cardiac life support, only 22% were long-term survivors. The survival rate when police deliver the first shock is 49%, compared with 43%
when paramedics initiate early defibrillation.
Mosesso et al. [15] reported on a similar type of project in the suburbs of Pittsburgh, Pennsylvania. A historical control was used from a time when the police were not equipped with automatic external defibrillators. The time from emergency call to delivery of the first shock was 11.8 min during the control period. After the police were equipped with automatic external defibrillators that time dropped to 8.7 min (P < 0.0001). Restoration of spontaneous circulation improved from 36% to 52% (P < 0.03), and survival more than doubled from 6% to 14% (P = 0.10).When the police arrived first during the control years, only 3% of patients with cardiac arrest survived. A
survival rate of 26% has been achieved since the police were issued with automatic external defibrillators (P < 0.05).
In 1991 Qantas Airlines became the first major operational airline to deploy automatic external defibrillators on overseas flights. Several airlines had trialled such strategies, but none continued them. O’Rourke and Donaldson reported on 5 years’ experience of the Qantas automatic external defibrillator programme [16]. Automatic external defibrillators were used 87 times: in 47 cases for monitoring – typically in patients with chest pain or palpitations – and in 40 for cardiac arrests. Twenty-two cardiac arrests occurred in the aircraft, while 18 occurred in the airport terminal. Six car- diac arrests in the aircraft were due to VF. Five of the six patients were suc- cessfully defibrillated with automatic external defibrillators, and two of six were long-term survivors with excellent neurological function. A major problem was uncovered when these initial data were reviewed, namely that most cardiac arrests in the aircraft were discovered early in VF. Cardiac arrest in airport terminals (18 of 40 cases) have a different pattern. Fifteen of these 18 patients had VF: each of the 15 was successfully defibrillated with the device. Four of these 15 patients were neurologically intact, long-term survivors.
Further support for a beneficial effect on survival of early defibrillation in the community is given by the data of the prospective cohort study con- ducted in Olmstead County [17, 18]. All patients who had an out-of-hospital cardiac arrest between November 1990 and December 2000, after implemen- tation of a local early defibrillation program, were followed to determine long-term survival and quality of life. Of the 200 patients with an out-of-hos- pital cardiac arrest with ventricular fibrillation, 145 (72%) survived to hospi- tal admission with spontaneous circulation, 84 (42%) survived to hospital discharge, and 79 (40%) were neurologically intact at discharge. Long-term survival was seen in 60 patients (30%). For the purposes of the analysis, patients with significant neurological impairment at discharge were consid- ered non-survivors. The mean length of follow-up was 4.8 years (standard deviation 3.0 years). The expected 5-year survival rate (79%) was identical to that among age-, sex- and disease-matched controls. The long-term survival and quality of life of patients resuscitated from a cardiac arrest has been demonstrated to be similar to that of control subjects from the general popu- lation.
Conclusions
There is no question but that early defibrillation will save lives. Despite the existence of well-developed emergency medical services with rapid-response
advanced life support capabilities, survival rates following out-of-hospital VF have remained low. Generally, these poor resuscitation rates are attrib- uted to delays in the performance of basic cardiopulmonary resuscitation by bystanders or delays in defibrillation.
The appropriateness of having defibrillators available in public places such as schools, apartment buildings, and offices is becoming clear. The PAD trial has demonstrated that training and equipping volunteers to attempt early defibrillation within a structured response system can increase the number of survivors to hospital discharge after out-of-hospital cardiac arrest in public locations. In airports, aeroplanes, casinos, and other high- risk locations, public use of external defibrillators should be strongly sup- ported. In addition, efforts by private individuals to obtain defibrillators for homes and businesses seem justified. Dual EMS systems incorporating defib- rillators have also shown good improvements in outcomes compared to EMS alone. In our opinion, public access defibrillation is here to stay.
References
1. Haskell WL (1978) Cardiovascular complications during exercise training of car- diac patients. Circulation 57:920–924
2. Cummins RO (1989) From concept to standard-of-care? Review of the clinical experience with automated external defibrillators. Ann Emerg Med 18:1269–1275 3. Stults KR, Brown DD, Schug VL et al (1984) Prehospital defibrillation performed by
emergency medical technicians in rural communities. N Engl J Med 310:219–223 4. Eisenberg MS, Bergner L, Hallstrom A (1979) Paramedic programs and out-of-
hospital cardiac arrest. I: factors associated with successful resuscitation. Am J Public Health 69:30–38
5. Nichol G, Hallstrom AP, Kerber R et al (1998) American Heart Association report on the second public access defibrillation conference, April 17–19, 1997. Circulation 97:1309–1314
6. Becker LB, Ostrander MP, Barrett J et al (1991) Outcome of CPR in a large metro- politan area: where are the survivors? Ann Emerg Med 19:179–186
7. Caffrey SL, Willoughby PJ, Pepe PE et al (2002) Public use of automated external defibrillators. N Engl J Med 347:1242–1247
8. Valenzuela TD, Roe GN, Clark LL et al (2000) Outcomes of rapid defibrillation by security officers after cardiac arrest in casinos. N Engl J Med 343:1206–1209 9. Hallstrom AP, Ornato JP, Weisfeldt M et al (2004) Public-access defibrillation and
survival after out-of-hospital cardiac arrest. Public Access Defibrillation Trial Investigators. N Engl J Med 351:637–646
10. Culley LL, Rea TD, Murray JA et al (2004) Public access defibrillation in out-of- hospital cardiac arrest: a community-based study. Circulation 109:1859–1863 11. Myerburg RJ, Fenster J, Velez M (2002) Impact of community-wide police car
deployment of automated external defibrillators on survival from out-of-hospital cardiac arrest. Circulation 106:1058–1064
12. Waalewijn RA, de Vos R, Tijssen JG et al (2001) Survival models for out-of-hospital cardiopulmonary resuscitation from the perspectives of the bystander, the first
responder, and the paramedic. Resuscitation 51:113–122
13. Capucci D, Aschieri MF, Piepoli MF et al (2002) Tripling survival from sudden car- diac arrest via early defibrillation without traditional education in cardiopulmo- nary resuscitation. Circulation 106:1065–1070
14. White RD, Asplin BR, Bugliosi TF et al (1996) High discharge survival rate after out-of-hospital ventricular fibrillation with rapid defibrillation by police and para- medics. Ann Emerg Med 28:480–485
15. Mosesso VN Jr, Davis EA, Auble TE et al (1998) Use of automated external defibril- lators by police officers for treatment of out-of-hospital cardiac arrest. Ann Emerg Med 32:200–207
16. O’Rourke MF, Donaldson E (1997) The first five years of the Quantas cardiac arrest program. J Am Coll Cardiol 29:404 (abs)
17. Mahapatra S, Bunch TJ, White RD et al (2005) Sex differences in outcome after ven- tricular fibrillation in out-of-hospital cardiac arrest. Resuscitation 65:197–202
