Early defibrillation: an advisory statement from the Advanced Life Support Working Group of the International Liaison Committee on Resuscitation

Association between the COVID-19 pandemic in 2020 and out-of-hospital cardiac arrest outcomes and bystander resuscitation efforts for working-age individuals in Japan: a nationwide observational and epidemiological analysis

BACKGROUND

Improving out-of-hospital cardiac arrest (OHCA) prognosis within the working-age population is important, but no studies have investigated the effects of COVID-19 pandemic specifically on the working-age population with OHCAs. We aimed to determine the association between the 2020 COVID-19 pandemic and OHCA outcomes and bystander resuscitation efforts among the working-age population.

METHODS

Prospectively collected nationwide, population-based records concerning 166 538 working-age individuals (men, 20-68 years; women, 20-62 years) with OHCA between 2017 and 2020 were assessed. We compared characteristics and outcome differences of the arrests between three prepandemic years (2017-2019) and the pandemic year 2020. The primary outcome was neurologically favourable 1-month survival (cerebral performance category 1 or 2). Secondary outcomes were bystander cardiopulmonary resuscitation (BCPR), dispatcher-assisted instruction for cardiopulmonary resuscitation (DAI-CPR), bystander-provided defibrillation (public access defibrillation (PAD)) and 1-month survival. We examined variations in bystander resuscitation efforts and outcomes among pandemic phase and regional classifications.

RESULTS

Among 149 300 OHCA cases, 1-month survival (2020, 11.2%; 2017-2019, 11.1% (crude OR (cOR) 1.00, 95% CI 0.97 to 1.05)) and 1-month neurologically favourable survival (7.3%-7.3% (cOR 1.00, 95% CI 0.96 to 1.05)) were unchanged; however, the neurologically favourable 1-month survival rate decreased in 12 of the most COVID-19-affected prefectures (7.2%-7.8% (cOR 0.90, 95% CI 0.85 to 0.96)), whereas it increased in 35 other prefectures (7.5%-6.6% (cOR 1.15, 95% CI 1.07 to 1.23)). Favourable outcomes decreased for OHCAs of presumed cardiac aetiology (10.3%-10.9% (cOR 0.94, 95% CI 0.90 to 0.99)) but increased for OHCAs of non-cardiac aetiology (2.5%-2.0% (cOR 1.27, 95% CI 1.12 to 1.44)). BCPR provision increased from 50.7% of arrests prepandemic to 52.3% (crude OR 1.07, 95% CI 1.04 to 1.09). Compared with 2017-2019, home-based OHCAs in 2020 increased (64.8% vs 62.3% (crude OR 1.12, 95% CI 1.09 to 1.14)), along with DAI-CPR attempts (59.5% vs 56.6% (cOR 1.13, 95% CI 1.10 to 1.15)) and multiple calls to determine a destination hospital (16.4% vs 14.5% (cOR 1.16, 95% CI 1.12 to 1.20)). PAD use decreased from 4.0% to 3.7% but only during the state of emergency period (7 April-24 May 2020) and in prefectures significantly affected by COVID-19.

CONCLUSIONS

Reviewing automated external defibrillator (AED) locations and increasing BCPR through DAI-CPR may help prevent pandemic-associated decreases in survival rates for patients with cardiac OHCAs.

Substantial variation exists in post-cardiac arrest outcomes across Michigan hospitals

AIM

Resuscitation from out of hospital cardiac arrest (OHCA) requires success across the entire chain of survival. Using a large state-wide registry, we characterized variation in clinical outcomes at hospital discharge in Michigan hospitals.

METHODS

We utilized the Michigan Cardiac Arrest Registry to Enhance Survival (CARES) and included adult OHCA subjects with return of spontaneous circulation (ROSC) from 2014 - 2017 that survived to hospital admission. 39 Michigan hospitals were included which managed >30 cases during the study period. Multilevel logistic regression, controlling for both subject characteristics and clustering of subjects within hospitals, assessed variation across hospitals in survival to hospital discharge and survival with cerebral performance category (CPC 1-2).

RESULTS

There were 5,486 CARES subjects that survived to hospital admission, and 4,690 met inclusion for analysis. Of 39 included hospitals, median survival to discharge was 31.3% (range 12.5%-46.7%) and median survival to discharge with CPC 1-2 was 25.0% (range 5.2%-42.2%). We identified 12-fold variation in the utilization of TTM by hospital (median 47.9%, range 6.7%-80.0%) for all admitted subjects. Similarly, there was nearly an eight-fold variation in LHC for all post-arrest subjects (median 22.1%, range 5.4%-42.2%). In multivariable analyses, median adjusted survival to discharge was 26.9% (range 18.1%-42.1%) and median adjusted survival to discharge with CPC 1-2 was 21.3% (range 9.6%-32.1%).

CONCLUSION

We observed substantial variation in clinical outcomes at discharge between Michigan hospitals, including a four-fold range of survival and eight-fold range of survival with CPC 1-2. This variation was ameliorated but still persisted in adjusted modeling. Variation in post arrest survival by hospital was not fully explained by available covariates, which suggests the possibility of improving post-arrest clinical outcomes at some hospitals via quality improvement activities.

Rationale and Strategies for Development of an Optimal Bundle of Management for Cardiac Arrest

Objectives

To construct a highly detailed yet practical, attainable roadmap for enhancing the likelihood of neurologically intact survival following sudden cardiac arrest.

Design Setting and Patients

Population-based outcomes following out-of-hospital cardiac arrest were collated for 10 U.S. counties in Alaska, California, Florida, Ohio, Minnesota, Utah, and Washington. The 10 identified emergency medical services systems were those that had recently reported significant improvements in neurologically intact survival after introducing a more comprehensive approach involving citizens, hospitals, and evolving strategies for incorporating technology-based, highly choreographed care and training. Detailed inventories of in-common elements were collated from the ten 9-1-1 agencies and assimilated. For reference, combined averaged outcomes for out-of-hospital cardiac arrest occurring January 1, 2017, to February 28, 2018, were compared with concurrent U.S. outcomes reported by the well-established Cardiac Arrest Registry to Enhance Survival.

Interventions

Most commonly, interventions and components from the ten 9-1-1 systems consistently included extensive public cardiopulmonary resuscitation training, 9-1-1 system-connected smart phone applications, expedited dispatcher procedures, cardiopulmonary resuscitation quality monitoring, mechanical cardiopulmonary resuscitation, devices for enhancing negative intrathoracic pressure regulation, extracorporeal membrane oxygenation protocols, body temperature management procedures, rapid cardiac angiography, and intensive involvement of medical directors, operational and quality assurance officers, and training staff.

Measurements and Main Results

Compared with Cardiac Arrest Registry to Enhance Survival (n = 78,704), the cohorts from the 10 emergency medical services agencies examined (n = 2,911) demonstrated significantly increased likelihoods of return of spontaneous circulation (mean 37.4% vs 31.5%; p < 0.001) and neurologically favorable hospital discharge, particularly after witnessed collapses involving bystander cardiopulmonary resuscitation and shockable cardiac rhythms (mean 10.7% vs 8.4%; p < 0.001; and 41.6% vs 29.2%; p < 0.001, respectively).

Conclusions

The likelihood of neurologically favorable survival following out-of-hospital cardiac arrest can improve substantially in communities that conscientiously and meticulously introduce a well-sequenced, highly choreographed, system-wide portfolio of both traditional and nonconventional approaches to training, technologies, and physiologic management. The commonalities found in the analyzed systems create a compelling case that other communities can also improve out-of-hospital cardiac arrest outcomes significantly by conscientiously exploring and adopting similar bundles of system organization and care.

ECMO in cardiac arrest and cardiogenic shock

Cardiogenic shock is an acute emergency, which is classically managed by medical support with inotropes or vasopressors and frequently requires invasive ventilation. However, both catecholamines and ventilation are associated with a worse prognosis, and many patients deteriorate despite all efforts. Mechanical circulatory support is increasingly considered to allow for recovery or to bridge until making a decision or definite treatment. Of all devices, extracorporeal membrane oxygenation (ECMO) is the most widely used. Here we review features and strategical considerations for the use of ECMO in cardiogenic shock and cardiac arrest.

The International Liaison Committee on Resuscitation-Review of the last 25 years and vision for the future

2017 marks the 25th anniversary of the International Liaison Committee on Resuscitation (ILCOR). ILCOR was formed in 1992 to create a forum for collaboration among principal resuscitation councils worldwide. Since then, ILCOR has established and distinguished itself for its pioneering vision and leadership in resuscitation science. By systematically assessing the evidence for resuscitation standards and guidelines and by identifying national and regional differences, ILCOR reached consensus on international resuscitation guidelines in 2000, and on international science and treatment recommendations in 2005, 2010 and 2015. However, local variation and contextualization of guidelines are evident by subtle differences in regional and national resuscitation guidelines. ILCOR's efforts to date have enhanced international cooperation, and progressively more transparent and systematic collection and analysis of pertinent scientific evidence. Going forward, this sets the stage for ILCOR to pursue its vision to save more lives globally through resuscitation.

Treatment and outcome of out-of-hospital cardiac arrest in outpatient health care facilities

AIM

We evaluated the frequency and effectiveness of basic and advanced life support (ALS) interventions by medical professionals when out-of-hospital cardiac arrest (OHCA) occurred in ambulatory healthcare clinics before emergency medical services (EMS) arrival.

METHODS

Non-traumatic OHCAs in adults were systematically characterized over a 15 year period by their occurrence in clinics, at home, or in non-medical public locations, and outcomes compared between matched cohorts from each group.

RESULTS

Among 7784 patients, 6098 OHCA occurred at home, 1612 in non-medical public locations and 74 in clinics. Compared to non-medical public locations, clinic patients with OHCA were older, more often women and more frequently shocked; clinic arrests were more often witnessed, less likely to be of cardiac cause and to occur before EMS arrival. Compared to home, more clinic arrests were witnessed, occurred after EMS arrival, had bystander CPR, shockable rhythms and were defibrillated. When OHCA occurred before EMS arrival, 51 of 56 clinic patients (91%) received CPR, a defibrillator applied to 23 (41%), 17 (30%) were shocked, 4 (7%) intubated, and 7 (13%) received intravenous medications from facility personnel. Of these, only pre-EMS defibrillator use was associated with improved outcome. Among matched patients, OHCA survival was higher in clinics than at home (42% vs 26%, p=0.029), but comparable to other public locations.

CONCLUSIONS

Survival from OHCA in clinics was comparable to non-medical public locations, and higher than at home. Alongside CPR, use of defibrillators was associated with improved survival and worth prioritizing over other interventions before EMS arrival regardless of OHCA location.

The fully automatic external cardioverter defibrillator: reality of a new meaningful scenario for in-hospital cardiac arrests

Sudden cardiac death is an unresolved problem which causes significant mortality and morbidity in both the community and in-hospital setting. Cardiac arrest is often caused by ventricular tachyarrhythmias which may be mostly interrupted by cardioversion or defibrillation. The single most critical factor for survival is the response time. Over the last 30 years, there have been virtually no procedural changes in the way hospitals address in-hospital resuscitation. A unique device has been developed that eliminates human intervention and assures defibrillation therapy is administered in seconds. This is accomplished with a fully automatic, external bedside monitor defibrillator designed to be prophylactically attached to hospitalized patients at risk of ventricular tachyarrhythmia. The safety and efficacy of the device has been demonstrated in multicenter US and European trials. Thus, this device allows a new scenario which may increase survival and enables meaningful redistribution of health resources.

Signal integral for optimizing the timing of defibrillation

OBJECTIVE

The possibility of successful defibrillation decreases with an increased duration of ventricular fibrillation (VF). Futile electrical shocks are inversely correlated with myocardial contractile function and long-term survival. Previous studies have demonstrated that various ECG waveform analyses predict the success of defibrillation. This study investigated whether the absolute amplitude of pre-shock VF waveform is likely to predict the success of defibrillation.

METHODS

ECG recordings of 350 out-of-hospital cardiac arrest (OOHCA) patients were obtained from the automated external defibrillator (AED) and analyzed by the method of signal integral. Successful defibrillation was defined as organized rhythm with heart rate ≥40beat/min commencing within one min of post-shock period and persisting for a minimum of 30s.

RESULTS

Signal integral was significantly greater in successful defibrillation than unsuccessful defibrillation (81.76±32.3mV vs. 34.9±15.33mV, p<0.001). The intersection of the sensitivity and specificity curve provided a threshold value of 51mV. The corresponding values of sensitivity, specificity, positive predictive and negative predictive values for successful defibrillation were 90%, 86%, 80% and 93%, respectively. The receiver operator curve further revealed that signal integral predicted the likelihood of successful defibrillation (area under the curve=0.949).

CONCLUSIONS

Signal integral predicted successful electrical shocks on patients with ventricular fibrillation and have potential to optimize the timing of defibrillation and reduce the number of electrical shocks.

ICU nurses' perceptions of potential constraints and anticipated support to practice defibrillation: a qualitative study

AIM

The study examines the experience of intensive care nurses in caring for patients in cardiac arrest, and their perceptions of introducing nurse-led defibrillation.

METHOD

This was a descriptive, exploratory and qualitative study at an intensive care unit (ICU) of an acute regional hospital in Hong Kong. Twelve registered nurses were purposefully selected for interview.

RESULTS

Although all the participants were trained in basic life support, only 50% were trained in advanced cardiac life support (ACLS), and those trained in ACLS described having limited opportunities to apply their defibrillation knowledge. Whilst participants believed that they were theoretically prepared to influence the patient's resuscitation outcomes, newly qualified nurses were reluctant to be accountable for defibrillation. In contrast, experienced nurses were more willing to perform nurse-led defibrillation. Support from management, cooperation between nurses and doctors, regular in-hospital 'real-drill' programmes, sponsorship for training, and the use of alternative defibrillation equipment should be considered to encourage nurse-led defibrillation in ICU settings.

CONCLUSION

Nurse-led defibrillation is an approach of delivering prompt care to critically ill patients, and a way ahead for intensive care nursing in Hong Kong. Emphasis on a consistent policy to promote nurse-led defibrillation practice is needed.

Electrical defibrillation: new technologies

Two-thirds of deaths from coronary disease occur in the pre-hospital phase and are caused by ventricular fibrillation or pulseless ventricular tachycardia, for which electrical defibrillation is the only effective treatment. The time delay between the onset of ventricular fibrillation and the administration of the first defibrillatory shock is the most important determinant for survival. To achieve the earliest defibrillation possible, rescuers others than physicians need to be able to initiate this treatment. The international scientific community strongly supports the concept of early defibrillation in the setting of a strong chain of survival. New technological developments of automated external defibrillators (AEDs) allowed the implementation of defibrillation by the first responding professional rescuer. As a consequence of the technological evolution in implantable defibrillators, much research has also been done on new defibrillation waveforms and alternative energy levels in external defibrillators. After initial animal research, human clinical investigation has shown that initial low energy (150J) nonprogressive (150J-150J-150J) impedance-adjusted biphasic waveform defibrillatory shocks for patients in out-of-hospital ventricular fibrillation are safe, acceptable and clinically effective. Reporting on outcome from cardiac arrest must be as uniform as possible to allow conclusions on performance of emergency medical service systems. The 'Utstein Style' nomenclature is a glossary of terms and a reporting guideline for uniform description of cardiac arrest, resuscitation, the emergency medical service (EMS) system and the outcome. Reports on experiences with AED programmes by traditional and non-traditional professional rescuers support the view that AEDs should not be implemented in EMS systems as an isolated intervention, but that efforts are equally needed to strengthen the other links of the chain of survival. The international scientific community (American Heart Association, International Liaison Committee on Resuscitation and European Resuscitation Council) have issued guidelines for the use of AEDs by EMS providers and first responders, and a universal treatment algorithm is proposed.

Prospective performance evaluation of emergency medical services for cardiac arrest in Lombardia: is something moving forward?

BACKGROUND

Limited data are available in our region on out-of-hospital treatment of cardiac arrest. The aim of this study is to evaluate whether the changes implemented in the emergency system (i.e. an increased number of basic life support and advance life support crews that were dispatched) produced the expected outcome improvements.

METHODS

(a)

EXPERIMENTAL DESIGN

data were prospectively collected on patients with sudden out-of-hospital cardiac arrest in three emergency dispatch centers for 3 months during two study periods, year 2000 and year 2003, differentiated only by the increase of qualified crews. Outcomes and survival were evaluated at 24 h and 1 month after the event. (b)

SETTING

out-of-hospital treatment. (c)

PATIENTS

352 (174 in the second study period) patients suffering cardiac arrest. (d)

INTERVENTIONS

the study was observational.

RESULTS

We could document, between the two study periods, stable 24 h (12.6 vs 9.1%) and 1 month survival (3.4 vs 5.8%, NS). Nevertheless, arrival time on site was significantly higher in the second period (from 8.3+/-3.3 to 10.1+/-5.4 min, P<0.05).

CONCLUSIONS

The strengthening of only one link of the chain-of-survival did not improve 1 month survival.

Demographic and temporal trends in out of hospital sudden cardiac death in Belfast

OBJECTIVE

To determine the epidemiology of out of hospital sudden cardiac death (OHSCD) in Belfast from 1 August 2003 to 31 July 2004.

DESIGN

Prospective examination of out of hospital cardiac arrests by using the Utstein style and necropsy reports. World Health Organization criteria were applied to determine the number of sudden cardiac deaths.

RESULTS

Of 300 OHSCDs, 197 (66%) in men, mean age (SD) 68 (14) years, 234 (78%) occurred at home. The emergency medical services (EMS) attended 279 (93%). Rhythm on EMS arrival was ventricular fibrillation (VF) in 75 (27%). The call to response interval (CRI) was mean (SD) 8 (3) minutes. Among patients attended by the EMS, 9.7% were resuscitated and 7.2% survived to leave hospital alive. The CRI for survivors was mean (SD) 5 (2) minutes and for non-survivors, 8 (3) minutes (p < 0.001). Ninety one (30%) OHSCDs were witnessed; of these 91 patients 48 (53%) had VF on EMS arrival. The survival rate for witnessed VF arrests was 20 of 48 (41.7%): all 20 survivors had VF as the presenting rhythm and CRI < or = 7 minutes. The European age standardised incidence for OHSCD was 122/100,000 (95% confidence interval 111 to 133) for men and 41/100,000 (95% confidence interval 36 to 46) for women.

CONCLUSION

Despite a 37% reduction in heart attack mortality in Ireland over the past 20 years, the incidence of OHSCD in Belfast has not fallen. In this study, 78% of OHSCDs occurred at home.

Defibrillation shock success estimation by a set of six parameters derived from the electrocardiogram

It is well known that in some cases defibrillator shocks cannot terminate ventricular fibrillation (VF). Repeated failed shocks often may worsen subsequent response to therapy. This study assesses the ability of six parameters derived from the surface electrocardiogram (ECG) to predict defibrillation shock outcome. Using stepwise discriminant analysis, we obtained several discriminant functions, yielding different combinations of sensitivity and specificity for detection of pre-shock ECG segments corresponding to successful versus unsuccessful shocks. The study was performed consecutively for 3, 4 and 5 s ECG time intervals. The prediction accuracy of 72.3% (61.8% sensitivity and 79.6% specificity) with five parameters and 3 s VF segment analysis prior to defibrillation shock could be considered acceptable for possible practical application in automatic external defibrillators.

Advances for treating in-hospital cardiac arrest: safety and effectiveness of a new automatic external cardioverter-defibrillator

OBJECTIVES

The purpose of this study was to prospectively analyze the performance and safety of a new programmable, fully automatic external cardioverter-defibrillator (AECD) in a European multicenter trial. BACKGROUND Although, the response time to cardiac arrest (CA) is a major determinant of mortality and morbidity, in-hospital strategies have not significantly changed during the last 30 years.

METHODS

Patients (n = 117) at risk of CA in monitored wards (n = 51) and patients undergoing electrophysiologic testing or implantable cardioverter-defibrillator (ICD) implantation (n = 66) were enrolled. The accuracy of the automatic response of the device to any change of rhythm (lasting >1 s and >4 beats) was confirmed by reviewing the simultaneously recorded Holter data and the programmed parameters.

RESULTS

During 1,240 h, 1,988 episodes of rhythm changes were documented. A total of 115 episodes lasted > or =10 s or needed treatment (pacing, n = 32; ICD, n = 51; AECD, n = 35) for termination. The device detected ventricular tachyarrhythmias with a sensitivity of 100% and specificity of 97.6% (true negatives, n = 1,454; true positives, n = 499; false positives, n = 35; false negatives, n = 0). The false positives were all caused by T-wave oversensing during ventricular pacing. There were no complications or adverse events. The mean response time was 14.4 s for those episodes needing a full charge of the capacitor.

CONCLUSIONS

This new AECD is safe and effective in detecting, monitoring, and treating spontaneous arrhythmias. This fully automatic device shortens the response time to treatment, and it is likely that it will significantly improve the outcome of patients with in-hospital CA.

Treatment of cardiac arrest with automatic external defibrillators: impact on outcome

Sudden cardiac death is the leading cause of death in the US and most developed nations. Ventricular fibrillation (VF) is the most common initial rhythm in survivors of cardiac arrest. The most important factor in determining survival from VF is the time from collapse to administration of the first defibrillation shock. Automatic external defibrillators (AEDs) have been developed and widely deployed in an attempt to reduce the time to defibrillation. Data on early defibrillation using AEDs has led to a number of public access defibrillator placements in the US and ongoing studies of public access AED use. The safety of lay person AED use is clear. Clearly some concentrated captive populations (e.g. airports, airplanes) may benefit from public access AEDs. Therefore, widespread AED education as a means of increasing public acceptance of lay person AED use must be a priority. As technology evolves costs will decline, however, the current economic reality requires careful consideration of the cost effectiveness of specific AED placement.

Public access defibrillation

Very early defibrillation, within the first few minutes of VF cardiac arrest, results in significantly improved survival rates [1,10-12,34]. Most EMS systems cannot consistently provide defibrillation within the first few minutes following cardiac arrest. Defibrillation within the first few minutes following collapse is potentially achievable through the use of AEDs and PAD [9-14,62]. The delivery of defibrillation with AEDs has been made more efficient through the use of impedance-compensated defibrillation, larger pad sizes, and biphasic waveforms [34]. The technology is simple and easy to use. Preliminary cost-effectiveness analysis indicates that PAD and first-responder defibrillation are economically as attractive as other interventions in cardiac arrest [44]. Effective PAD requires significant investment in time, energy, informed planning, and rigorous quality improvement; however, the benefits are enormous. Reported VF survival rates can approach 50% or higher [11,12,62]. PAD provides the potential opportunity to transform cardiac arrest into a survivable event for most victims by making the community the ultimate coronary care unit.

Automated external defibrillators and first responders: a satisfaction survey

PRIMARY OBJECTIVE

Automated external defibrillators (AEDs) are used with increasing frequency in the United States by first responders (FR) such as police officers (PO) or firefighters (FF). However, FR satisfaction with use of AEDs has not been investigated. We hypothesized that FR satisfaction is comparable with that of paramedics (PA) and that, among those who have defibrillated with AEDs, those who have restored a pulse before PA arrival have a higher level of satisfaction than those who have not restored a pulse.

MATERIALS AND METHODS

A 21-item questionnaire with closed answers was sent to FR and PA in four communities. Each answer was scored 0, 1 or 2. A score between 10 and 16 correlated with the highest satisfaction level.

RESULTS

276 out of 311 questionnaires were returned (89%). Two hundred and eleven respondents (35 PA, 70 FF and 106 PO) had used an AED and 99 FF and PO had restored a pulse before PA arrival. The satisfaction level of PO, FF and PA was high as demonstrated by the scores: 13.26, 13.07 and 13.39, respectively. Use of AED and pulse restoration resulted in higher scores than those of groups who had been trained only and who had not restored a pulse.

CONCLUSION

FR demonstrated a high level of satisfaction with using AEDs, and also had a favorable attitude toward implementation of AED use. Restoration of a pulse was clearly a factor responsible for a higher satisfaction. This positive attitude should encourage further implementation of early defibrillation programs in non-medical first responder settings.

Defibrillators in public places: the introduction of a national scheme for public access defibrillation in England

OBJECTIVE

To implement a government-led project-the 'Defibrillators in Public Places' Initiative-to deploy Automated External Defibrillators (AEDs) in public places.

BACKGROUND

A Defibrillator Advisory Committee (DAC) was formed to assist the government with the implementation of the project. Its particular tasks were to: recommend criteria for the selection, training and assessment of those individuals likely to use the devices; procure the equipment necessary for the implementation of the project; procure the training services required for the implementation of the project; ensure the AEDs are sited where they are most likely to be of benefit; establish a mechanism to audit the use of this equipment and the outcome of this initiative. To co-ordinate this project a National Project Manager was appointed. Consultation with Ambulance Services NHS Trusts established the places where cardiac arrest occurred under circumstance where the availability of a defibrillator might be most likely to be effective. Defibrillators were procured under the direction of the NHS Purchasing and Supply Agency in conjunction with medical advisors. Devices that were reliable, safe, simple in operation and with good data retrieval systemes were selected. Training contracts were awarded under the direction of the NHS Purchasing and Supply Agency in conjunction with medical and educational advisors. Organisations with accredited training experience and possessing the appropriate administrative and data handling abilities were selected. The ability to undertake training in an area concordant with current NHS regions was an essential requirement. In the first stage of implementation, pilot trials were successfully established at sites where persons were willing to be trained in the use of automated defibrillators. Arrangements for national progress of the project were made on the basis of the experience gained at pilot sites. A robust system for monitoring the outcome of the project has been established in partnership with the Resuscitation Council UK. The long-term success of this innovative project requires: Continuing central administrative support in the short to medium term. Central audit and data collection. The results of this project should contribute to national databases being established by the Resuscitation Council UK. Continuing adequate funding. The recognition that the provision of defibrillation to the victims of cardiac arrest is a key feature of the NHS.

Out-of-hospital defibrillation with automated external defibrillators: postshock analysis should be delayed

STUDY OBJECTIVE

The American Heart Association protocols for use of automated external defibrillators (AEDs) recommend that a rhythm analysis be done immediately after each defibrillation attempt. However, shock is often followed by electrical silence or marginally organized electrical activity before ventricular fibrillation (VF) or ventricular tachycardia (VT) recurs. The optimal timing of postshock analysis for identification of recurrent VF/VT is unknown. This study examines the time to recurrence of VF/VT after a defibrillation attempt with AED.

METHODS

Over an 18-month period, all tapes from patients with out-of-hospital cardiac arrest who received shocks at least once with an AED were screened for recurrent VF/VT. All cases come from a single emergency medical services system providing basic life support, defibrillation with AED, and intubation with an esophageal-tracheal twin-lumen airway device (Combitube) for a population of 633,511 individuals. Pediatric and traumatic cases were excluded. When VF/VT recurred within 3 minutes of the defibrillation attempt, rhythm strips were printed and included in the study. Two cardiology fellows, blinded to the study objectives, measured the time from defibrillation to recurrent VF/VT for each strip.

RESULTS

Over the study period, 222 tapes from 96 patients met the inclusion criteria. Only 44 (20%) occurrences of VF/VT had recurred within 6 seconds of defibrillation, 162 (73%) at 60 seconds, and 200 (90%) at 90 seconds.

CONCLUSION

Eighty percent of VF/VT recurred more than 6 seconds after defibrillation and were missed when using current American Heart Association AED protocols. Subsequent analysis should be postponed until at least 30 seconds after defibrillation. Performing 30 seconds of chest compressions after defibrillation before subsequent AED rhythm analysis would increase AED identification of VF/VT to 52%.

Optimal Response to Cardiac Arrest study: defibrillation waveform effects

INTRODUCTION

Advances in early defibrillation access, key to the "Chain of Survival", will depend on innovations in defibrillation waveforms, because of their impact on device size and weight. This study compared standard monophasic waveform automatic external defibrillators (AEDs) to an innovative biphasic waveform AED.

MATERIAL AND METHODS

Impedance-compensated biphasic truncated exponential (ICBTE) and either monophasic truncated exponential (MTE) or monophasic damped sine (MDS) AEDs were prospectively, randomly assigned by date in four emergency medical services. The study design compared ICBTE with MTE and MDS combined. This subset analysis distinguishes between the two classes of monophasic waveform, MTE and MDS, and compares their performance to each other and to the biphasic waveform, contingent on significant overall effects (ICBTE vs. MTE vs. MDS). Primary endpoint: Defibrillation efficacy with < or =3 shocks. Secondary endpoints: shock efficacy with < or =1 shock, < or =2 shocks, and survival to hospital admission and discharge. Observations included return of spontaneous circulation (ROSC), refibrillation, and time to first shock and to first successful shock.

RESULTS

Of 338 out-of-hospital cardiac arrests, 115 had a cardiac aetiology, presented with ventricular fibrillation, and were shocked by an AED. Defibrillation efficacy for the first "stack" of up to 3 shocks, for up to 2 shocks and for the first shock alone was superior for the ICBTE waveform than for either the MTE or the MDS waveform, while there was no difference between the efficacy of MTE and MDS. Time from the beginning of analysis by the AED to the first shock and to the first successful shock was also superior for the ICBTE devices compared to either the MTE or the MDS devices, while again there was no difference between the MTE and MDS devices. More ICBTE patients achieved ROSC pre-hospital than did MTE patients. While the rates of ROSC were identical for MTE and MDS patients, the difference between ICBTE and MDS was not significant. Rates of refibrillation and survival to hospital admission and discharge did not differ among the three populations.

CONCLUSIONS

ICBTE was superior to MTE and MDS in defibrillation efficacy and speed and to MTE in ROSC. MTE and MDS did not differ in efficacy. There were no differences among the waveforms in refibrillation or survival.

Automatic external defibrillators: changing the way we manage ventricular fibrillation

OBJECTIVE

To discuss recent developments in automatic defibrillation and to review the evidence that first-responders equipped with automatic external defibrillators (AEDs) improve survival from out-of-hospital cardiac arrest.

DATA SOURCES

MEDLINE search from 1966 to 1999 (articles in English only) and examination of bibliographies.

STUDY SELECTION

Published studies of out-of-hospital cardiac arrest and first-responders equipped with AEDs. Studies had to have a control group and to report survival to hospital discharge from ventricular fibrillation (VF).

DATA EXTRACTION

Six studies met the selection criteria (two prospective randomised trials, two prospective controlled trials, and one cohort study and one retrospective study, both with historical controls).

DATA SYNTHESIS

A random effects meta-analysis of odds ratios for survival from VF.

CONCLUSIONS

Meta-analysis suggests that equipping first-responders with AEDs increases the probability of survival to hospital discharge after out-of-hospital cardiac arrest (odds ratio, 1.74; 95% CI, 1.27-2.38; P < 0.001). However, most of the studies lacked sufficient power to draw definitive conclusions. Until the impact of wide deployment of AEDs is fully understood, first-responder defibrillation in Australia should only occur as part of coordinated multicentre research studies.

Seven years' experience with early defibrillation by police and paramedics in an emergency medical services system

PRIMARY OBJECTIVE

To assess the outcome of patients with out-of-hospital cardiac arrest with ventricular fibrillation as the presenting rhythm in an emergency medical services system utilizing a combined police/paramedic response to provide early defibrillation.

MATERIALS AND METHODS

Police and paramedics were dispatched from law enforcement and ambulance communications centers, respectively. First-arriving personnel delivered initial shocks, all using automated external defibrillators. Patients were classified according to response to initial shocks: restoration of pulses with shocks only or in need of advanced life support, including epinephrine. Discharge survival was defined as return to home without disabling neurologic injury.

RESULTS

Over the 7-year period of study 131 patients presented with ventricular fibrillation: 58 were first treated by police and 73 by paramedics. Restoration of pulses with shocks only and discharge survival were not different in police and paramedic groups, with overall survival of 40% (53 of 131 patients). Among the survivors, 19% (18/95 patients) obtained a spontaneous circulation only after administration of epinephrine and other ALS interventions.

CONCLUSION

Both restoration of a functional circulation, without need for advanced life support interventions, and discharge survival without neurologic disability are very dependent upon the rapidity with which defibrillation is accomplished, regardless of who delivers the shocks. In addition, a smaller but significant number of patients who require ALS interventions, including epinephrine, for restoration of a spontaneous circulation survive to discharge. Short time differences, on the order of 1 min, are significant determinants of both immediate response to shocks and discharge survival.

Successful automatic external defibrillator operation by people trained only in basic life support in a simulated cardiac arrest situation

OBJECTIVE

To show whether in an in-hospital cardiac arrest, early defibrillation can also be performed by hospital staff trained only in basic life support.

BACKGROUND

The International Liaison Committee on Resuscitation (ILCOR) endorses the concept that in many settings non-medical individuals should be allowed and encouraged to use defibrillators.

METHODS

Five different groups of hospital staff were evaluated whether they were able to correctly operate an automatic external defibrillator in a simulated sudden cardiac arrest situation without any prior instruction. The participants were assigned either to the 'basic life support-trained' group (BLS, n = 40, or to the 'advanced life support-trained' group (ALS, n = 40).

RESULTS

All persons of the 'only BLS-trained' group delivered the three sequential ('stacked') shocks with the automatic external defibrillator when persistent ventricular fibrillation was simulated. The 'ALS-trained' persons successfully delivered the three shocks with the automatic external defibrillator in 98% of the cases. When this group used a conventional defibrillator, only 88% were able to deliver the three shocks, however they were able to do it significantly more quickly.

CONCLUSION

Using an automatic defibrillator without any prior instruction, even persons trained only in BLS were able to deliver three sequential shocks in a simulated persistent ventricular fibrillation cardiac arrest.

[Implanted automatic defibrillator after ventricular fibrillation treated with semi-automatic defibrillation]

We report two cases of out-of-hospital ventricular fibrillation treated without delay, with basic life support practiced by the witness, followed by a successful defibrillation by paramedics with a semi-automatic defibrillator. In the subsequent month, a cardioverter-defibrillator was implanted. In one patient, a ventricular tachycardia occurring 10 months later and a ventricular fibrillation 9 months later in the other respectively, were successfully reversed by the implanted defibrillator. These two cases illustrate the value of the "survival chain" concept (undelayed alert, basic life support by witness, early defibrillation by paramedics with a semi-automatic defibrillator, advanced life support by a physician) as well as the benefit of the implanted cardioverter-defibrillator.