Use of the automatic external defibrillator in the management of out-of-hospital cardiac arrest

Advances in Cardiopulmonary Resuscitation

This article focuses on important advances in the science of cardiopulmonary resuscitation (CPR) in the last decade that have led to a significant improvement in understanding the complex physiology of cardiac arrest and critical interventions for the initial management of cardiac arrest and postresuscitation treatment. Special emphasis is given to the basic simple ways to improve circulation, vital organ perfusion pressures, and the grave prognosis of sudden cardiac death.

Public Access Defibrillation

In the United States, 250,000 people die from a cardiac arrest every year. Despite a well established emergency medical response system, survival from out-of-hospital cardiac arrest remains poor in United States cities. Paramount to achieving successful resuscitation of a cardiac arrest victim is provision of early defibrillation. Among patients that arrest due to a ventricular fibrillation, the likelihood of survival decreases by 10% for every minute of delay in defibrillation. In 1995, the American Heart Association challenged the medical industry to develop a defibrillator that could be placed in public settings, used safely by lay responders, and provide earlier defibrillation to cardiac arrest victims. Over the last decade, there have been significant technological advancements in automated external defibrillators (AEDs), and clinical studies have demonstrated their benefits and limitations in various public locations. This article discusses the technologic features of the modern AED and the current data available on the use of AEDs in public settings.

The role of automated external defibrillators in athletics

CONTEXT

Sudden cardiac arrest is the leading cause of death in young athletes. The purpose of this review is to summarize the role of automated external defibrillators and emergency planning for sudden cardiac arrest in the athletic setting.

EVIDENCE ACQUISITION

Relevant studies on automated external defibrillators, early defibrillation, and public-access defibrillation programs were reviewed. Recommendations from consensus guidelines and position statements applicable to automated external defibrillators in athletics were also considered.

RESULTS

Early defibrillation programs involving access to automated external defibrillators by targeted local responders have demonstrated a survival benefit for sudden cardiac arrest in many public and athletic settings.

CONCLUSION

Schools and organizations sponsoring athletic programs should implement automated external defibrillators as part of a comprehensive emergency action plan for sudden cardiac arrest. In a collapsed and unresponsive athlete, sudden cardiac arrest should be suspected and an automated external defibrillator applied as soon as possible, as decreasing the time interval to defibrillation is the most important priority to improve survival in sudden cardiac arrest.

Survival trends in the United States following exercise-related sudden cardiac arrest in the youth: 2000-2006

BACKGROUND

Sudden cardiac arrest is the leading cause of death in young athletes. However, limited studies have examined survival rates after exercise-related sudden cardiac arrest in the youth.

OBJECTIVE

The Purpose of this study was to monitor exercise-related sudden death in the United States and to assess survival trends following exercise-related sudden cardiac arrest in the youth.

METHODS

From January 1, 2000, through December 31, 2006, exercise-related sudden death events in young individuals were identified through a systematic search of public media reports. Media reports were reviewed to clarify case circumstances and relation to exercise, cause of death, outcome, and use of a defibrillator. The study used an observational cohort design with weekly searches and updates to the database.

RESULTS

During the 7-year period from 2000-2006, 486 total cases of exercise-related sudden cardiac arrest were identified in elementary school (age 5-11 years), middle school (age 11-14 years), high school (age 14-18 years), and college (age 18-22 years) individuals in the United States, with an average of 69 cases per year (range 48-96 years). Eighty-three percent (405/486) of victims were male and 17% (81/486) were female, with a male-to-female ratio of 5:1. Overall survival during this time period was 11% (55/486), with a range of 4% to 21% survival per year. There was a statistically significant trend toward improved survival in recent years (P = .035). Females were more likely to survive sudden cardiac arrest than were males (21% vs 9%, P = .001).

CONCLUSION

Survival following exercise-related sudden cardiac arrest in the youth has been universally poor over the last 7 years in the United States, despite a recent trend toward improved survival. Improved reporting systems are needed to accurately monitor these events, and strategies to improve outcomes from exercise-related sudden cardiac arrest in the youth, such as improved emergency response planning and public access defibrillation programs, should be considered.

Inter Association Task Force recommendations on emergency preparedness and management of sudden cardiac arrest in high school and college athletic programs: a consensus statement

OBJECTIVE

To assist high school and college athletic programs prepare for and respond to a sudden cardiac arrest (SCA). This consensus statement summarizes our current understanding of SCA in young athletes, defines the necessary elements for emergency preparedness, and establishes uniform treatment protocols for the management of SCA.

BACKGROUND

Sudden cardiac arrest is the leading cause of death in young athletes. The increasing presence of and timely access to automated external defibrillators (AEDs) at sporting events provides a means of early defibrillation and the potential for effective secondary prevention of sudden cardiac death. An Inter-Association Task Force was sponsored by the National Athletic Trainers' Association to develop consensus recommendations on emergency preparedness and management of SCA in athletes.

RECOMMENDATIONS

Comprehensive emergency planning is needed for high school and college athletic programs to ensure an efficient and structured response to SCA. Essential elements of an emergency action plan include establishing an effective communication system, training of anticipated responders in cardiopulmonary resuscitation and AED use, access to an AED for early defibrillation, acquisition of necessary emergency equipment, coordination, and integration of on-site responder and AED programs with the local emergency medical services system, and practice and review of the response plan. Prompt recognition of SCA, early activation of the emergency medical services system, the presence of a trained rescuer to initiate cardiopulmonary resuscitation, and access to early defibrillation are critical in the management of SCA. In any collapsed and unresponsive athlete, SCA should be suspected and an AED applied as soon as possible for rhythm analysis and defibrillation if indicated.

Recent advances and controversies in adult cardiopulmonary resuscitation

Since its introduction more than four and half decades ago, the science of cardiopulmonary resuscitation has been enriched with a significant amount of scientific evidence. This in turn has led to the birth of new evidence based guidelines for resuscitation published by the European Resuscitation Council and the American Heart Association in late 2005. This article aims to review the recent advances and controversies in the science of resuscitation.

In-hospital resuscitation

A recent world expert conference on resuscitation and emergency cardiac care led to evidence-based international guidelines for cardiopulmonary resuscitation (CPR). Several changes to CPR interventions were recommended, and will have to be implemented into clinical practice. The poor prognosis of patients who suffer in-hospital cardiac arrest may be improved with developments in CPR interventions. In the present review the most important changes recommended by the new CPR guidelines and the latest promising CPR investigations are described, focusing on their impact on in-hospital resuscitation.

Automated external defibrillators in Washington State high schools

BACKGROUND

The placement of automated external defibrillators (AEDs) in schools and public sporting venues is a growing national trend.

OBJECTIVE

To determine the prevalence and use of AEDs in Washington State high schools and to examine the existing emergency preparedness for sudden cardiac arrest (SCA).

DESIGN

Cross-sectional survey.

SETTING

High schools in Washington State.

PARTICIPANTS

The principal at each high school in the Washington Interscholastic Activities Association (n = 407) was invited to complete a web-based questionnaire using the National Registry for AED Use in Sports (http://www.AEDSPORTS.com).

MAIN OUTCOME MEASUREMENTS

The primary outcome measures studied included AED prevalence and location, funding for AEDs, AED training of school personnel, coordination of AED placement with local emergency response agencies, and prior AED use.

RESULTS

118 schools completed the survey (29% response rate). 64 (54%) of the schools have at least one AED on school grounds (mean 1.6, range 1-4). The likelihood of AED placement increased with larger school size (p = 0.044). 60% of AEDs were funded by donations, 27% by the school district and 11% by the school or athletic department itself. Coaches (78%) were the most likely to receive AED training, followed by administrators (72%), school nurses (70%) and teachers (48%). Only 25% of schools coordinated the implementation of AEDs with an outside medical agency and only 6% of schools coordinated with the local emergency medical system. One school reported having used an AED previously to treat SCA in a basketball official who survived after a single shock. The estimated probability of AED use to treat SCA was 1 in 154 schools per year.

CONCLUSIONS

Over half of Washington State high schools have an AED on school grounds. AED use occurred in <1% of schools annually and was effective in the treatment of SCA. Funding of AED programmes was mostly through private donations, with little coordination with local emergency response teams. Significant improvement is needed in structuring emergency response plans and training targeted rescuers for an SCA in the high-school setting.

Comparison of hands-off time during CPR with manual and semi-automatic defibrillation in a manikin model

BACKGROUND

Rhythm analysis with current semi-automatic external defibrillators (AEDs) requires mandatory interruptions of chest compressions that may compromise the outcome after cardiopulmonary resuscitation (CPR). We hypothesised that interruptions would be shorter when the defibrillator was operated in manual mode by trained and certified ambulance personnel.

MATERIALS AND METHODS

Sixteen pairs of ambulance personnel operated the defibrillator (Lifepak((R))12) in both semi-automatic (AED) and manual (MED) mode in a randomised, cross-over manikin CPR study, following the ERC 2000 Guidelines.

RESULTS

Median time from last chest compression to shock delivery (with interquartile range) was 17s (13, 18) versus 11s (6, 15) (mean difference (95% CI) 6s (2, 10), p=0.004). Similarly, median time from shock delivery to resumed chest compressions was 25s (22, 26) versus 8s (7, 12) (median difference 13s, p=0.001) in the AED and MED groups, respectively. While sensitivity for identifying ventricular fibrillation (VF) in both modes and specificity in the AED mode were 100%, specificity was 89% in manual mode. Thus, some unwarranted shocks resulting in hands-off time (time without chest compressions) were given in manual mode. However, mean hands-off-ratio (time without chest compressions divided by total resuscitation time) was still lower, 0.2s (0.1, 0.3) versus 0.3s (0.28, 0.32) in manual mode, mean difference 0.10s (0.05, 0.15), p=0.001.

CONCLUSION

Paramedics performed CPR with less hands-off time before and after shocks on a manikin with manual compared to semi-automatic defibrillation following the 2000 Guidelines. However, 12% of the shocks given manually were inappropriate.

Inter-association task force recommendations on emergency preparedness and management of sudden cardiac arrest in high school and college athletic programs: a consensus statement

OBJECTIVE

To assist high school and college athletic programs prepare for and respond to sudden cardiac arrest (SCA). This consensus statement summarizes our current understanding of SCA in young athletes, defines the necessary elements for emergency preparedness, and establishes uniform treatment protocols for the management of SCA.

BACKGROUND

SCA is the leading cause of death in young athletes. The increasing presence of and timely access to automated external defibrillators (AEDs) at sporting events provides a means of early defibrillation and the potential for effective secondary prevention of sudden cardiac death. An Inter-Association Task Force was sponsored by the National Athletic Trainers' Association to develop consensus recommendations on emergency preparedness and management of SCA in athletes.

RECOMMENDATIONS

Comprehensive emergency planning is needed for high school and college athletic programs to ensure an efficient and structured response to SCA. Essential elements of an emergency action plan include establishing an effective communication system, training of anticipated responders in cardiopulmonary resuscitation and AED use, access to an AED for early defibrillation, acquisition of necessary emergency equipment, coordination and integration of onsite responder and AED programs with the local emergency medical services system, and practice and review of the response plan. Prompt recognition of SCA, early activation of the emergency medical services system, the presence of a trained rescuer to initiate cardiopulmonary resuscitation, and access to early defibrillation are critical in the management of SCA. In any collapsed and unresponsive athlete, SCA should be suspected and an AED applied as soon as possible for rhythm analysis and defibrillation if indicated.

Feasibility of basic emergency medical technicians to perform selected advanced life support interventions

OBJECTIVE

Emergency medical technician-basic (EMT-B) providers often provide the initial care to victims of out-of-hospital cardiac arrest. While automated external defibrillators enable EMT-B providers to deliver rescue shocks, patients in cardiac arrest may require additional interventions that EMT-B providers may not presently deliver. We sought to evaluate the feasibility of training EMT-B providers to provide additional cardiac resuscitation procedures using the laryngeal mask airway (LMA) and intraosseous (IO) access.

METHODS

In this prospective observational study, we trained 18 EMT-B providers to use the LMA and IO drill (EZ-IO) in a three-hour educational session. Working in two-person teams, the rescuers performed a simulated ventricular fibrillation resuscitation. We evaluated placement success as well as elapsed time to placement of the LMA and EZ-IO.

RESULTS

EMT-B providers successfully placed the LMA in 14 of 18 scenarios (78%; 95% confidence interval, 52% to 94%), with a mean of two attempts for placement. Subjects successfully placed the EZ-IO in 17 of 18 scenarios (94%; 95% confidence interval, 73% to 100%), all on the first attempt. The median time to LMA placement following the third shock was 109 seconds (interquartile range, 58-158) and the median time to EZ-IO placement was 72 seconds (interquartile range, 50-93) after LMA placement.

CONCLUSIONS

EMT-B providers demonstrated moderate success in performing advanced-level cardiac resuscitation interventions. These observations suggest potential for expanding the role of basic-level rescuers in cardiopulmonary resuscitation.

La desfibrilación temprana en la comunidad: romper barreras para salvar vidas

It is considered that in Spain, every year, we have more than 24,500 out-of-hospital cardiac arrests. Around 85% of these are secondary to ventricular fibrillation, with possibility of reversion in more than 90% if defibrillation is performed in the first minute of arrhythmia. However, if we delay this defibrillation, survival possibilities disappear in a few minutes. Clinical advances in last decades have not achieved satisfactory results in the treatment of cardiac arrest as survival rates at hospital discharge do not exceed 7%. Aware of this situation, the International Scientific Societies are recommending decreasing time to defibrillation, advising, at best, a time less than five minutes between the 112-call (emergency) and adequate electric discharge. Development of automated defibrillators in Emergency Medical Systems and their use by <<first responders>> of <<non-health care>> emergency services (police, fire fighters, etc) contribute to reach this objective. Because of this, Emergency Medical Systems are modifying their assistance strategies, to implement the early defibrillation as <<key to survival>>. Literature showed the effective value of automated defibrillators in the public areas but their efficiency level is less than that reached with the Emergency Services. Efficiency depends on multiple factors such as type of installation, accessibility level to emergency medical services or incidence rate of sudden cardiac arrest. Thus, their introduction should be preceded by a cost-effectiveness study. Effectiveness of automated defibrillators at home, where up to 80% of cardiac arrest are produced, has still not been evaluated. Nevertheless, in the USA, its marketing with this indication has been authorized.

A reference automated external defibrillator provider course for Europe

BACKGROUND

Scientific evidence is scarce in relation to the effectiveness of different methods of teaching automated external defibrillator (AED) use to laypeople. A reference course is needed in order to test new courses or methods against a comparative standard.

OBJECTIVE

To propose a reference AED provider course that can be used as a comparator when testing new courses or teaching methods.

METHODS

All national resuscitation councils that are represented in the European Resuscitation Council were sent a questionnaire about the AED provider courses run by them or under their auspices.

RESULTS

Sixteen national resuscitation councils responded to the enquiry. Apart from the individual course timetables, there was remarkable consistency amongst the European countries as regards organisation, structure, content and methods.

CONCLUSIONS

A reference AED provider course for laypeople, based on a synthesis of existing European courses, is suggested as a tool for research. Prior completion of a basic life support provider course is mandatory. Course duration is 2 h 45 min (excluding breaks), with 1 h 40 min practice time for the participants, 25 min for theory, 20 min for practical demonstrations by the instructor and 20 min for introduction, discussion and closure. A manual is distributed at the start of the course. The ratio of instructors to participants is one to six. Lectures are interactive between the instructor and the class. AED use is practised in groups of six participants. Participants prove their competency by means of a formal test that simulates a cardiac arrest scenario. Using this course as a comparator during research into the methodology of AED teaching would provide a reference against which other courses could be tested.

A public access defibrillation programme in non-inpatient hospital areas

INTRODUCTION

Automatic external defibrillators (AED) have proven to be valuable and life saving for out of hospital cardiac arrests. Their use in hospital arrests is less well documented, but they offer the opportunity to improve survival in the hospital setting also.

METHODS

The implementation of a public access defibrillation (PAD) programme at a tertiary care hospital is described, with reference specifically to targeting areas where time from arrest to arrival of defibrillation would be greater than 3 min.

RESULTS

Nine AEDs were placed in areas of the hospital distant from inpatient or outpatient floors. The locations of the AEDs were chosen based on a 3 min walk from currently available defibrillators to all areas of the hospital, including parking garages and walkways from building to building. In this programme AED use in non-inpatient hospital locations resulted in the resuscitation of a patient in ventricular fibrillation.

CONCLUSION

PAD in non-inpatient hospital settings can be life saving and similar programmes should be considered for other hospitals.

Effects of a rate smoothing algorithm for prevention of ventricular arrhythmias: Results of the Ventricular Arrhythmia Suppression Trial (VAST)

BACKGROUND

Rate smoothing, which is available in some pacemakers and implantable cardioverter defibrillators (ICDs), has been used to prevent Torsades de Pointes in patients with long QT syndrome. Its efficacy in general ventricular arrhythmia prevention has not been determined.

OBJECTIVES

The purpose of the Ventricular Arrhythmia Suppression Trial (VAST) was to prospectively investigate whether rate smoothing could significantly reduce the incidence of ventricular tachyarrhythmias in a large, broad population of patients with ICDs.

METHODS

Five hundred sixty-nine patients were enrolled at 57 participating centers and implanted with a commercially available Guidant ICD. A single-blinded crossover design was used in which each patient was randomized at implant to one of two treatment sequences: either rate smoothing on (RS On) followed by rate smoothing off (RS Off), or RS Off followed by RS On. This mode sequence was randomly determined and assigned in a 1:1 fashion using randomized permuted blocks by site. Each mode was followed for 6 months. Programming of rate smoothing was prescribed as 12% Down and 12% Up for the duration of the RS On period.

RESULTS

Of enrolled patients, 281 were randomized to RS Off followed by RS On, and 288 to RS On followed by RS Off. With RS On, 75 (23%) patients experienced a reduction in arrhythmias, 76 (23%) saw an increase in arrhythmias, and the remaining 176 (54%) had no difference. No significant difference (P = .58) in frequency of arrhythmias with RS On vs RS Off was found.

CONCLUSION

Rate smoothing does not result in a reduction in ventricular arrhythmias in a heterogeneous population of patients receiving ICDs.

Future shock: automatic external defibrillators

PURPOSE OF REVIEW

This review provides a practical overview of the performance capabilities of automatic external defibrillators (AEDs), and of advances in technology and dissemination programmes for these devices.

RECENT FINDINGS

Arrhythmia analysis by AEDs is extremely reliable in most settings (sensitivity 81-100%, specificity 99.9-97.6%). Accurate detection of arrhythmias has also been demonstrated in children, leading the US Food and Drug Administration to approve the use of several AEDs in children aged 8 years or younger. Factors that potentially may reduce the quality of arrhythmia detection are the presence of wide complex supraventricular tachycardia and location of an arrythmic event near to high-power lines. AED use by professional basic life support providers resulted in increased survival in the prehospital setting. However, provision of AEDs to nonmedical rescue services did not result in universal improvement in patient outcome. Public access defibrillation programmes have led to higher rates of survival from cardiac arrest. The role of AEDs in hospitals has yet to be elucidated, although in-hospital mortality from ventricular arrhythmias has been shown to decrease following AED deployment.

SUMMARY

Given the correct setting, AEDs can ensure that defibrillation is not limited by lack of medical knowledge or difficulties in decision making. However, event-related variables and operator-related factors, that are yet to be determined, can significantly affect the efficacy of automatic external defibrillation.

Use of automated external defibrillators at NCAA Division I universities

PURPOSE

The placement of automated external defibrillators (AED) at public sporting events is a growing national trend. The purpose of the present study was to investigate the prevalence, past use, and cost of implementing AED at university sporting venues.

METHODS

Questionnaires were sent to the head athletic trainer at all Division I NCAA universities (N = 326) and responses collected between August and November 2003.

RESULTS

Completed surveys were returned by 244 institutions (75% response rate). Ninety-one percent (221/244) had AED for an average of 3.3 yr (range 1-13) with a median of four AED per institution (range 1-30). There were 35 cases of AED use for sudden cardiac arrest with 77% (27/35) occurring in older nonstudents, 14% (5/35) in intercollegiate athletes, and 3% (1/35) in a student nonintercollegiate athlete (information unavailable in two cases). The immediate resuscitation rate was 54% (19/35). A shock was delivered in 21 cases with a resuscitation rate of 71% (15/21). None of the intercollegiate athletes were successfully resuscitated. The average cost per AED was 2460 US dollars. In a 10-yr model (expected useful life of an AED), the cost per life immediately resuscitated was 52,400 US dollars, and the estimated cost per life-year gained ranged 10,500 US dollars to 22,500 US dollars.

CONCLUSIONS

Most Division I universities have AED available at selected sporting venues. Although no benefit was demonstrated for intercollegiate athletes, AED were successfully used in older nonstudents with cardiac arrest with a favorable long-term cost analysis.

Out-of-hospital resuscitation in Estonia: a bystander-witnessed sudden cardiac arrest

OBJECTIVE

To evaluate the results of the first epidemiological study on out-of-hospital resuscitation in Estonia.

METHODS

A prospective cohort study of 2108 consecutive standardized reports on out-of-hospital resuscitation attempts from 1 January 1999 to 31 December 2002 was conducted according to the Utstein style.

RESULTS

In all, 67.3% (1419/2108) of the cardiac arrests were of presumed cardiac aetiology and 60.2% (854/1419) of them were bystander-witnessed. Of these, the 28% bystander cardiopulmonary resuscitation was initiated, and the first rhythm was recorded as ventricular fibrillation or pulseless ventricular tachycardia in 40% of the cases. In the subgroup of patients with bystander-witnessed cardiac arrest of cardiac origin, 10.7% (91/854) were discharged alive in good cerebral performance categories and 7.7% were alive at the 1-year follow-up. The chances of survival increased if the median response time interval was <6 min, cardiac arrest occurred in a public place, patients received bystander cardiopulmonary resuscitation and had an initial rhythm of ventricular fibrillation or pulseless ventricular tachycardia. The discharge rate was 24% (82/343) in the subgroup of patients who had bystander-witnessed cardiac arrest of cardiac origin and an initial rhythm of ventricular fibrillation or pulseless ventricular tachycardia. In this subgroup, the survival rate was 42.6% (40/94) in Tartu urban area, 16.9% (22/130) in Tallinn urban area and 16.8% (20/119) in other regions of Estonia (mostly urban and suburban areas).

CONCLUSION

The results demonstrate that despite the progress in the management of out-of-hospital cardiac arrest in Estonia, only one centre (Tartu) achieves a better survival rate. Further improvements are needed to raise the quality of the Estonian emergency medical services system, especially in rural areas.

First appropriate use of automated external defibrillator in an infant

Automated external defibrillators (AEDs) are currently not recommended for use in children under 1 year of age. We report the first description of successful AED defibrillation in an infant using a 50 J shock and provide rationale for employing these life-saving devices in infants at risk for sudden cardiac death.

International Resuscitation Network Registry: design, rationale and preliminary results

There is a lack of high-quality information about the effectiveness of resuscitation interventions and international differences in structure, process and outcome after out-of-hospital cardiac arrest and cardiopulmonary resuscitation because data are not collected uniformly. An internet-based international registry could make such evaluations possible, and enable the conduct of large randomized controlled trials of resuscitation therapies. A prospective international cohort study was performed that included 571 infants, children and adults (a) who experienced cardiac arrest requiring chest compressions or external defibrillation, (b) outside the hospital in the study communities and (c) upon whom resuscitation was attempted by EMS personnel. Cardiac arrest was defined as lack of responsiveness, breathing or movement in individuals for whom the EMS system is activated for whom an arrest record is completed. All data were collated via a secure and confidential web-based method by using automated forms processing software with appropriate variable range checks, logic checks and skip rules. Median number of missing responses for each variable was 0 (interquartile range 0, 0). Twenty-seven percent of the patients had a first recorded rhythm of ventricular fibrillation or ventricular tachycardia, 60% had a witnessed arrest, and 34% received bystander CPR. Mean time from call to arrival on scene was 7.1+/-5.1 min. Six percent of the patients survived to hospital discharge. The resuscitation process was highly variable across centers, and survival and neurological outcome were also significantly and independently different across centers. This study shows that it is possible to collect data prospectively describing the structure, process and outcome associated with cardiac arrest in multiple international sites via the internet. Therefore, it is feasible to conduct adequately powered randomized trials of resuscitation therapies in international settings.

Implementation of community-based public access defibrillation in the PAD trial

BACKGROUND

The Public Access Defibrillation (PAD) Trial was a randomized, controlled trial designed to measure survival to hospital discharge following out-of-hospital cardiac arrest (OOH-CA) in community facilities trained and equipped to provide PAD, compared with community facilities trained to provide cardiopulmonary resuscitation (CPR) without any capacity for defibrillation.

OBJECTIVES

To report the implementation of community-based lay responder emergency response programs in 1,260 participating facilities recruited for the PAD Trial in the United States and Canada.

METHODS

This was a descriptive study of the characteristics of participating facilities, volunteers, and automated external defibrillator (AED) placements compiled by the PAD Trial, and a qualitative study of factors that facilitated or impeded implementation of emergency lay responder programs using focus groups of PAD Trial site coordinators.

RESULTS

The PAD Trial enrolled 1,260 community facilities (14.8% residential), with 20,400 lay volunteers (mean +/- standard deviation = 13.4 +/- 10.7 per facility) trained to respond to OOH-CA. The 598 locations randomized to receive AEDs required 2.7 +/- 1.8 AEDs per facility. Volunteer attrition was high, 36% after two years. Barriers to recruitment and implementation included identification of appropriate "at-risk" facilities, lack of interest or fear of litigation by a facility key decision maker, lack of motivated potential volunteer responders, training and retraining resource requirements, and lack of an existing communication/response infrastructure.

CONCLUSIONS

These data indicate that implementation of community-based lay responder programs is feasible in many types of facilities, although these programs require substantial resources and commitment, and many barriers to implementation of effective PAD programs exist.

[Technical requirements for early defibrillation: what are the capabilities of automated external defibrillators]

Modern automated external defibrillators (AEDs) offer a variety of technical improvements which increase the efficacy of early defibrillation, facilitate the application by not or minimally trained persons and improve safety. The development of biphasic shocks allows better myocardial protection, the use of lithium batteries, and a marked decrease of AEDs, in size. Microprocessors realize complex acoustic and visual prompts which lead the user through all steps of cardiopulmonary resuscitation (CPR) according to current guidelines. The design of AEDs has been simplified; many devices provide only a single button which can be used for all active processes. Memory functions record the whole CPR with all details which can be transferred to other computers and analyzed off-line. The introduction of AEDs has reduced the delay between collapse and defibrillation to less than 4 min in several studies thus increasing the success of CPR and the proportion of patients dismissed from hospital alive and without neurological deficit. Up to 93% of untrained volunteers were able to successfully complete defibrillation with the use of an AED, sixth-form pupils without experience in CPR were only few sec slower with an AED than staff of emergency medical services. The ability to perform CPR after defibrillation guided by the AED depends primarily on the clarity of acoustic prompts which have to consider the terms and abbreviations of the respective language. Currently available AEDs surpass performance goals of the AHA. However, all devices exhibit advantages and disadvantages which will be discussed in this review.

[First responder defibrillation in the USA, Europe and Germany--prerequisites, experiences, perspectives]

Sudden out-of-hospital cardiac arrest is a leading cause of death and only 5-8% of patients survive such event. Defibrillation is the mose effective treatment and should performed within 5 minutes; however, its effectiveness diminishes with each passing minute. "Early defibrillation" is the use of automated external defibrillators (AEDs) by trained public-safety personnal ("first responder"), whereas "public access" defibrillation describes AED use by persons who have no specific AED training. Several studies in the US and in Europe show that first responder defibrillation will increase the number of survivors of out-of-hospital cardiac arrest compared to paramedics. This is caused by a shorter "call-to-arrival-time" in first responders compared to paramedics. In Europe, programs for the use of automated external defibrillators exist only occasionally. Reasons for this are the lack of open-mindedness, logistic and legal problems. In Germany, there are only few AED programs with promising results. At the present time, placement of automated external defibrillators in public places frequented by a large number of susceptible people will increase overall survival. However, placement of AEDs in all public places is still debatable and further studies are necessary to estimate the potential impact of publicc access defibrillators.

Out-of-hospital cardiac arrest and survival: an epidemiological analysis of emergency service reports in a large city in Japan

BACKGROUND

The factors that influence survival of out-of-hospital cardiac arrest in Japan have not been fully investigated.

METHODS AND RESULTS

The official emergency service record was used to investigate 1,600 patients for whom cardiopulmonary resuscitation was attempted by the city's emergency personnel. Only 45 (2.8%) patients survived for 1 month. The survival rate was 9.8% in the patients under 20 years of age, with a marked decreasing trend to 0.8% in the patients aged 80 years or older. The rate peaked at 4.8% on Sunday and bottomed out at 0.5% on Thursday, forming a distinct sine curve. The survival rate was 9.9% when an ambulance arrived at the scene within 4 min, with a steep drop to 2.5% when 4-7 min elapsed. However, the rate was not significantly different by the interval to hospital. Although bystander resuscitation did not significantly affect the survival, paramedics on board significantly improved the rate (3.5% vs 1.6%). Multivariate analysis confirmed that age, day of the week, place, interval to ambulance's arrival, and personnel on board were independently associated with the probability of survival.

CONCLUSIONS

Quick arrival of a paramedic team would improve the survival after out-of-hospital cardiac arrest. General education of lifesaving techniques would be another key factor.

Evaluating the quality of prehospital cardiopulmonary resuscitation by reviewing automated external defibrillator records and survival for out-of-hospital witnessed arrests

OBJECTIVES

Without an easy method to monitor the performance of prehospital cardiopulmonary resuscitation (CPR), earlier studies have not been able to assess the quality of CPR. In this study, we have used a new approach to evaluate prehospital CPR performance and the impact on outcome using data retrieved from the automatic external defibrillators (AED).

MATERIALS AND METHODS

Electrocardiography (ECG) and voice records from AED data cards from 633 out-of-hospital cardiac arrests (OHCA) were reviewed. Fifty-two witnessed cardiac arrests in ventricular fibrillation (VF) requiring post-shock CPR underwent an independent, structured review by two physicians. The adequacy of prehospital CPR was defined on the basis of noticeable deflection of the ECG with chest compressions, the actual number of chest compressions delivered per minute, and the continuity of prehospital CPR at the scene and during transport. Outcome measures included return of spontaneous circulation (ROSC) and survival to hospital admission and discharge.

RESULTS

The quality of prehospital CPR was judged as adequate in 15 (29%, 95%; CI: 18-42%) and inadequate in 37 (71%, 95%; CI: 58-82%) of the consensus. Adequate CPR performance resulted in a higher rate of ROSC at the scene (53% versus 8%, 95% CI of the difference 14-76%), and survival to hospital discharge (53% versus 8%, 95% CI of the difference 14-76%). Two reviewers agreed on whether CPR was adequate in 92.3% of cases, with a kappa of 0.82.

CONCLUSIONS

The quality of prehospital CPR is associated with a greater likelihood of survival in witnessed VF arrests in need of post-shock CPR. The potential of widely available electrocardiography and voice records in AEDs in providing a convenient and real-time evaluation of prehospital CPR should be explored further.

Prevention of Sudden Cardiac Death

Sudden cardiac death (SCD), presumably because of ventricular tachyarrhythmias, remains one of the major challenges of contemporary cardiology. Major randomized controlled trials conducted in patients with coronary artery disease (CAD) with the aim of primary prevention of SCD are providing insights. Several large-scale studies have demonstrated that treatment with beta-blockers, angiotensin-converting enzyme inhibitors, aldosterone antagonists, and statins results not only in a reduction in all-cause mortality but specifically also in SCD. On top of this optimized pharmacological therapy, implantable cardioverter-defibrillators (ICD) further decrease the risk of overall and SCD mortality in carefully selected patient groups. The sum of these trials indicates, however, that the benefit associated with ICD therapy is most prominent in patients with chronic stable CAD. In contrast, patients early after myocardial infarction derive less benefit from ICD treatment, presumably because of a high competing risk of non-arrhythmic cardiovascular death. Optimized pharmacological therapy, together with the ICD, can substantially improve the prognosis of high-risk CAD patients.

Results of the first five years of the prehospital automatic external defibrillation project in Singapore in the “Utstein style”

In 1994, all emergency medical services (EMS) ambulance officers in Singapore were trained to perform pre-hospital defibrillation with semi-automated external defibrillators (AED). All non-traumatic cardiac arrest patients over 10 years old were included, excluding those who were obviously dead and children below 36 kg. The data were collected by the ambulance officers according to the Utstein guidelines. From 1 February 1994 to 31 January 1999; resuscitation was attempted in 968 non-trauma cardiac arrests. Fifteen percent of the cases were of non-cardiac origin. The overall survival rate was 40/968 (4.1%, 95% CI 2.9-5.6%). Of 968 patients, 22/136 (16.2%, 95% CI 10.4-23.5%), 18/622 (2.9%, 95% CI 1.7-4.5%) and 0/210 (0%, 95% CI 0-1.7%) survived in the EMS witnessed, bystander witnessed and un-witnessed groups, respectively (P < 0.001). Within the EMS witnessed group, those with an initial rhythm of VF/VT had a higher survival rate (30.6%) than those without VF/VT (4.1%). P < 0.001, OR = 10.3, 95% CI 2.9-36.9. Similarly, the VF/VT survival rate in the bystander witnessed group (4.5%) was higher than the non-VF/VT (1.0%) (P = 0.011, OR = 4.4, 95% CI 1.3-15.4). The survival rate of patients with bystander witnessed VF/VT arrest who received bystander CPR was 9.4% compared to 1.0% in those who did not (P = 0.037, OR = 4.4, 95% CI 1.01-20.1). Our survival rate of bystander witnessed VF/VT arrest is comparable to large metropolitan cities in the USA. The determinants of survival include EMS witnessed arrest and VF/VT arrest. Increased quantity and quality of bystander CPR rate may improve the outcome in bystander witnessed cardiac arrest.

Public Defibrillation

The Public Access Defibrillation (PAD) trial was a prospective, randomized, controlled study designed to compare the number of persons surviving to hospital discharge after experiencing an out-of-hospital cardiac arrest (OOH-CA) among "community units" randomized to receive cardiopulmonary resuscitation (CPR) only or CPR plus an automated external defibrillator (AED). In 24 centers across the United States and Canada, 993 community units, composed of 1260 individual facilities, trained more than 19,000 layperson responders in CPR-only or CPR+AED. Survival to hospital discharge in the CPR+AED arm was double that of the CPR-only arm (30 vs 15, P = .03; RR = 2.0, 95% CI [1.07-3.77]). Intense focus on facility infrastructure, including responder recruitment and training, communication, evaluation, and oversight, was necessary for implementing the emergency response systems for the trial. Use of an AED within this structured response system can increase the number of survivors to hospital discharge after OOH-CA. Trained nonmedical responders can use AEDs safely and effectively.