First-responder Defibrillation Research Articles

Association of Public Health Initiatives With Outcomes for Out-of-Hospital Cardiac Arrest at Home and in Public Locations

Little is known about the influence of comprehensive public health initiatives according to out-of-hospital cardiac arrest (OHCA) location, particularly at home, where resuscitation efforts and outcomes have historically been poor. To describe temporal trends in bystander cardiopulmonary resuscitation (CPR) and first-responder defibrillation for OHCAs stratified by home vs public location and their association with survival and neurological outcomes. This observational study reviewed 8269 patients with OHCAs (5602 [67.7%] at home and 2667 [32.3%] in public) for whom resuscitation was attempted using data from the Cardiac Arrest Registry to Enhance Survival (CARES) from January 1, 2010, through December 31, 2014. The setting was 16 counties in North Carolina. Patients were stratified by home vs public OHCA. Public health initiatives to improve bystander and first-responder interventions included training members of the general population in CPR and in the use of automated external defibrillators, teaching first responders about team-based CPR (eg, automated external defibrillator use and high-performance CPR), and instructing dispatch centers on recognition of cardiac arrest. Association of resuscitation efforts with survival and neurological outcomes from 2010 through 2014. Among home OHCA patients (n = 5602), the median age was 64 years, and 62.2% were male; among public OHCA patients (n = 2667), the median age was 68 years, and 61.5% were male. After comprehensive public health initiatives, the proportion of patients receiving bystander CPR increased at home (from 28.3% [275 of 973] to 41.3% [498 of 1206], P < .001) and in public (from 61.0% [275 of 451] to 70.5% [424 of 601], P = .01), while first-responder defibrillation increased at home (from 42.2% [132 of 313] to 50.8% [212 of 417], P = .02) but not significantly in public (from 33.1% [58 of 175] to 37.8% [93 of 246], P = .17). Survival to discharge improved for arrests at home (from 5.7% [60 of 1057] to 8.1% [100 of 1238], P = .047) and in public (from 10.8% [50 of 464] to 16.2% [98 of 604], P = .04). Compared with emergency medical services-initiated CPR and resuscitation, patients with home OHCA were significantly more likely to survive to hospital discharge if they received bystander-initiated CPR and first-responder defibrillation (odds ratio, 1.55; 95% CI, 1.01-2.38). Patients with arrests in public were most likely to survive if they received both bystander-initiated CPR and defibrillation (odds ratio, 4.33; 95% CI, 2.11-8.87). After coordinated and comprehensive public health initiatives, more patients received bystander CPR and first-responder defibrillation at home and in public, which was associated with improved survival.

STATEWIDE INITIATIVES IMPROVE THE CARE AND OUTCOMES OF PATIENTS WITH OUT-OF-HOSPITAL CARDIAC ARREST AT HOME AND IN PUBLIC LOCATIONS: RESULTS FROM THE HEARTRESCUE PROJECT

Statewide public health initiatives improve bystander cardiopulmonary resuscitation (CPR) and first-responder defibrillation for out-of-hospital cardiac arrest (OHCA). Little is known about the impact of these initiatives according to OHCA location, particularly at home, where resuscitation efforts

The role of bystanders, first responders, and emergency medical service providers in timely defibrillation and related outcomes after out-of-hospital cardiac arrest: Results from a statewide registry.

Defibrillation by bystanders and first responders has been associated with increased survival, but limited data are available from non-metropolitan areas. We examined time from 911-call to defibrillation (according to who defibrillated patients) and survival in North Carolina. Through the Cardiac Arrest Registry to Enhance Survival, we identified 1732 defibrillated out-of-hospital cardiac arrests from counties with complete case capture (population 2.7 million) from 2010 to 2013. Most patients (60.9%) were defibrillated in > 10 min. A minority (8.0%) was defibrillated < 5 min; most of these patients were defibrillated by first responders (51.8%) and bystanders (33.1%), independent of location of arrest (residential or public). Bystanders initiated cardiopulmonary resuscitation (CPR) in 49.0% of cases and defibrillated 13.4% of those. Survival decreased with increasing time to defibrillation (< 2 min: 59.1%; 2 to < 5 min: 38.5%; 5-10 min: 33.1%; > 10 min: 13.2%). Odds of survival with favorable neurologic outcome adjusted for age, sex, and bystander CPR improved with faster defibrillation (<2 min: OR 7.73 [95% CI 3.19-18.73]; 2 to < 5 min: 3.78 [2.45-5.84]; 5-10 min: 3.16 [2.42-4.12]; > 10 min: reference). Bystanders and first responders were mainly responsible for defibrillation within 5 min, independent of location of arrest. Bystanders initiated CPR in half of the cardiac arrest cases but only defibrillated a minority of those. Timely defibrillation and defibrillation by bystanders and/or first responders were strongly associated with increased survival. Strategic efforts to increase bystander and first-responder defibrillation are warranted to increase survival after out-of-hospital cardiac arrest.

Association of Bystander and First-Responder Intervention With Survival After Out-of-Hospital Cardiac Arrest in North Carolina, 2010-2013.

Out-of-hospital cardiac arrest is associated with low survival, but early cardiopulmonary resuscitation (CPR) and defibrillation can improve outcomes if more widely adopted. To examine temporal changes in bystander and first-responder resuscitation efforts before arrival of the emergency medical services (EMS) following statewide initiatives to improve bystander and first-responder efforts in North Carolina from 2010-2013 and to examine the association between bystander and first-responder resuscitation efforts and survival and neurological outcome. We studied 4961 patients with out-of-hospital cardiac arrest for whom resuscitation was attempted and who were identified through the Cardiac Arrest Registry to Enhance Survival (2010-2013). First responders were dispatched police officers, firefighters, rescue squad, or life-saving crew trained to perform basic life support until arrival of the EMS. Statewide initiatives to improve bystander and first-responder interventions included training members of the general population in CPR and in use of automated external defibrillators (AEDs), training first responders in team-based CPR including AED use and high-performance CPR, and training dispatch centers in recognition of cardiac arrest. The proportion of bystander and first-responder resuscitation efforts, including the combination of efforts between bystanders and first responders, from 2010 through 2013 and the association between these resuscitation efforts and survival and neurological outcome. The combination of bystander CPR and first-responder defibrillation increased from 14.1% (51 of 362; 95% CI, 10.9%-18.1%) in 2010 to 23.1% (104 of 451; 95% CI, 19.4%-27.2%) in 2013 (P < .01). Survival with favorable neurological outcome increased from 7.1% (82 of 1149; 95% CI, 5.8%-8.8%) in 2010 to 9.7% (129 of 1334; 95% CI, 8.2%-11.4%) in 2013 (P = .02) and was associated with bystander-initiated CPR. Adjusting for age and sex, bystander and first-responder interventions were associated with higher survival to hospital discharge. Survival following EMS-initiated CPR and defibrillation was 15.2% (30 of 198; 95% CI, 10.8%-20.9%) compared with 33.6% (38 of 113; 95% CI, 25.5%-42.9%) following bystander-initiated CPR and defibrillation (odds ratio [OR], 3.12; 95% CI, 1.78-5.46); 24.2% (83 of 343; 95% CI, 20.0%-29.0%) following bystander CPR and first-responder defibrillation (OR, 1.70; 95% CI, 1.06-2.71); and 25.2% (109 of 432; 95% CI, 21.4%-29.6%) following first-responder CPR and defibrillation (OR, 1.77; 95% CI, 1.13-2.77). Following a statewide educational intervention on rescusitation training, the proportion of patients receiving bystander-initiated CPR and defibrillation by first responders increased and was associated with greater likelihood of survival. Bystander-initiated CPR was associated with greater likelihood of survival with favorable neurological outcome.

Abstract 308: Metropolitan Police First-Responder Defibrillation Significantly Increases Survival Rates

Background: Sudden cardiac arrest (SCA) is one of the most common causes of death in western, industrialized countries. The hospital discharge rate after Out-of-Hospital Cardiac Arrests (OHCA with cardiac etiology and first monitored rhythm shockable) was 2011 24.7% in Vienna (Austria). The overall bystander CPR rate was 42% and in only 4% of the cases an AED was used by laypeople. Therefore, we wanted to assess whether a police first responder program with immediately initiated resuscitation measures (chest compression and use of an AED within the first three minutes) may increase survival rates after SCA in the Austrian capital. Methods: The police forces in Vienna were provided with 112 AEDs (52 in police cars / 60 at police stations) and CPR plus AED training. Emergency dispatching was organized such as AED-equipped police (P-AED) and conventional emergency medical service (EMS) responders were simultaneously dispatched to patients with assumed cardiac arrest. One month survival states of cardiac arrest victims provided with P-AED were compared to patient outcomes when EMS was the sole responder. Results: From August 2013 to April 2014, a 50% hospital discharge rate was observed for victims with initial ventricular fibrillation (VF) in the P-AED group, compared to 26% for standard EMS treatment. However, the overall survival benefit was diluted by the fact - that 75% of the initial rhythms were non-shockable, reducing the absolute survival to 10%. There have been 701 OHCA in this time, but due to lack of information, only 654 were included in the study. Figure 1 shows the outcome in detail. Conclusion: Use of AEDs by police first responders significantly increases survival and hospital discharge in VF patients. There was no benefit for victims with non-shockable rhythms yet. Further campaigning will be necessary, to increase the number of police first responder commitments and to implement an Austria wide P-AED system.

Submersion and Early-Onset Acute Respiratory Distress Syndrome: A Case Report

Drowning is a common cause of accidental death, particularly in younger people, and acute respiratory failure is common in these patients. This case report describes a healthy 18-year-old man who suffered a cardiorespiratory arrest due to submersion while swimming in a freshwater lake. First-responder cardiopulmonary resuscitation and defibrillation using an automated external defibrillator resulted in a return of spontaneous circulation. The patient was evacuated to a tertiary care center by a rotor-wing air medical crew. The crew experienced difficulties in oxygenating and ventilating the patient because of early-onset acute respiratory distress syndrome (ARDS). This case report describes the pathophysiology and prehospital management of a patient with suspected early-onset ARDS secondary to drowning. This case report is unique because it describes the oxygenation and ventilation difficulties encountered in managing this patient in the transport setting, and possible strategies to deal with these difficulties. Finally, this case report highlights the prehospital bypass decision-making process for patients requiring specialized medical care.

A first city-wide early defibrillation project in a German city: 5-year results of the Bochum against sudden cardiac arrest study

BackgroundImmediate defibrillation is the decisive determinant of prognosis in patients suffering from cardiac/circulatory arrest caused by ventricular fibrillation (VF). Therefore, various national and international associations recommend that first responders use defibrillators as soon as possible and also recommend public access to early defibrillation programmes. Here we report the results of the first city-wide early defibrillation project in a large German urban area.MethodsThere were 155 automated external defibrillators (AEDs) put into operation in the Bochum municipal area, and 6,294 people took part in cardiopulmonary resuscitation (CPR) and AED training. Free, accessible AEDs were installed in places with large volumes of people. Additionally, emergency forces were progressively equipped with AEDs.ResultsTwelve AED administrations prior to the arrival of an emergency physician were recorded and analysed over a period of 5 years (08/2004-08/2009). Rhythm analysis via AED demonstrated VF in seven cases, non-malignant dysrhythmias in four cases and asystole in one case. Two of the seven patients with VF were successfully defibrillated and survived cardiac/circulatory arrest without any neurological sequelae. Eight of the 12 AED applications were performed by laymen. The mean time between switching the unit on and applying the electrodes to the patient was 39 seconds (SD +/-20 sec). On average, another 20 seconds elapsed before the AED recommendation of "shock delivery" was displayed, and a total of 96 seconds elapsed before shock administration (± 56 sec).ConclusionConsistent with other reports, our findings show that the organisation of a city-wide initiative by a project office combining public access and first-responder defibrillation programmes can be safe, feasible and successful. Our experiences confirm that strategic planning of AED placement is a prerequisite for successful, cost-effective resuscitation.

Cost-effectiveness analysis of a rural/urban first-responder defibrillation program

Objective. To analyze the cost-effectiveness of a proposed first-responder defibrillation program in a small rural area in comparison with a recently initiated first-responder program in an adjoining urban center in southwestern Ontario. The purpose of the analysis was to quantify the expected benefits of the proposed program to determine whether the costs are justified. Methods. This analysis was conducted on the city of Waterloo (population 80,000 over 25 square miles) and the adjoining rural township of Wellesley (population 8,000 over 105 square miles). The township has volunteer fire department first responders with basic life support (BLS), and basic life support/defibrillation (BLS-D) ambulances as the second tier; whereas the city's full-time fire department has recently adopted a first-responder defibrillation (BLS-D) program backed up by the same BLS-D ambulance service. The most relevant costs identified were the capital costs of the defibrillators, ancillary equipment, and biomedical service for preventive maintenance and routine nonwarranty work. Response intervals and percentage of patients found in ventricular fibrillation were projected and sensitivity analysis was applied. Results. The projected cost per life saved is $6,776 (C) in the urban area and $49,274 (C) in the rural area using an incremental save rate of 6%. Applying sensitivity analysis to the data, the save rate varied from 2% to 10%, resulting in a cost per life saved of $20,328 (C) and $4,066 (C), respectively, in the urban community. For the rural area, the cost per life saved ranged from $147,821 (C) (2%) to $29,564 (C) (10%). Even the worst-case save rate for the urban center [2%; $20,328 (C)] is significantly less than the best-case save rate [10%; $29,564 (C)] for the rural area. Conclusions. The cost per life saved for a rural first-responder defibrillation program is significantly more expensive than one for an urban center. However, the cost per life saved is still economical compared with common treatments for other life-threatening illnesses. PREHOSPITAL EMERGENCY CARE 2000;4:43-47

A S URVEY OF F IRST-RESPONDER F IREFIGHTERS ' A TTITUDES , O PINIONS, AND C ONCERNS ABOUT T HEIR A UTOMATED E XTERNAL D EFIBRILLATOR P ROGRAM

Objective. To identify barriers to first-responder automated external defibrillator (AED) use by determining firefighter attitudes, opinions, and concerns about their AED program. Methods. An anonymous survey was mailed to all firefighters in a municipal department that had had first-responder defibrillation for more than two years. A follow-up survey was mailed to all nonrespondents. The survey requested firefighter demographics, comfort and experience with AED, definition of DOA (dead on arrival), and opinion of the program. Results. Of 749 firefighters surveyed, 686 responded (92%). The respondents had an average of 12 ± 8 years of experience; 66% felt very comfortable using the AED and 3% felt very uncomfortable. The respondents had applied an AED to a patient a median of 2 times (range 0–30); 24% had never applied an AED. Eighty-three percent reported they had been on the scene of an out-of-hospital cardiac arrest when their AED was not used for at least one patient. Predominant reasons for not applying an AED included the ambulance arrived “soon enough” (72%), the ambulance arrived first (63%), the patient was DOA (61%), and the patient had a do-not-resuscitate (DNR) order (32%). Eighty-one percent of the respondents correctly listed at least one clinical finding that defines DOA. Ninety-nine percent felt they should continue the AED program. The respondents gave numerous suggestions for improving the program, including being able to visualize the rhythm, increasing their level of care, and improved AED training. Conclusions. Municipal first response firefighters view their AED program favorably despite infrequently applying an AED. The appropriateness of withholding defibrillation because a secondary response unit will arrive “soon enough” should be reviewed. The definition of DOA should be reviewed to ensure that viable patients are not denied defibrillation.

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.

Automatic external defibrillators: changing the way we manage ventricular fibrillation.

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. MEDLINE search from 1966 to 1999 (articles in English only) and examination of bibliographies. 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). 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). A random effects meta-analysis of odds ratios for survival from VF. 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.

C OST -E FFECTIVENESS A NALYSIS OF A R URAL /U RBAN F IRST - RESPONDER D EFIBRILLATION P ROGRAM

Objective. To analyze the cost-effectiveness of a proposed first-responder defibrillation program in a small rural area in comparison with a recently initiated first-responder program in an adjoining urban center in southwestern Ontario. The purpose of the analysis was to quantify the expected benefits of the proposed program to determine whether the costs are justified. Methods. This analysis was conducted on the city of Waterloo (population 80,000 over 25 square miles) and the adjoining rural township of Wellesley (population 8,000 over 105 square miles). The township has volunteer fire department first responders with basic life support (BLS), and basic life support/defibrillation (BLS-D) ambulances as the second tier; whereas the city's full-time fire department has recently adopted a first-responder defibrillation (BLS-D) program backed up by the same BLS-D ambulance service. The most relevant costs identified were the capital costs of the defibrillators, ancillary equipment, and biomedical service for preventive maintenance and routine nonwarranty work. Response intervals and percentage of patients found in ventricular fibrillation were projected and sensitivity analysis was applied. Results. The projected cost per life saved is $6,776 (C) in the urban area and $49,274 (C) in the rural area using an incremental save rate of 6%. Applying sensitivity analysis to the data, the save rate varied from 2% to 10%, resulting in a cost per life saved of $20,328 (C) and $4,066 (C), respectively, in the urban community. For the rural area, the cost per life saved ranged from $147,821 (C) (2%) to $29,564 (C) (10%). Even the worst-case save rate for the urban center [2%; $20,328 (C)] is significantly less than the best-case save rate [10%; $29,564 (C)] for the rural area. Conclusions. The cost per life saved for a rural first-responder defibrillation program is significantly more expensive than one for an urban center. However, the cost per life saved is still economical compared with common treatments for other life-threatening illnesses.

PREHOSPITAL PEARLS, PITFALLS, AND UPDATES

The rapid proliferation of emergency medical services in the United States has led to numerous controversies concerning delivery, interventions, and efficacy. This article presents a brief overview of the important literature in this expanding field. Important clinical topics, including first-responder defibrillation, rapid sequence intubation, and airway management, are reviewed. In addition, several important medicolegal topics pertaining to pre-hospital care are analyzed.

Relationship of timeliness of paramedic advanced life support interventions to outcome in out-of-hospital cardiac arrest treated by first responders with defibrillators: Ann Emerg Med 1996; 27/5: 638–648

Abstract Study objective: We sought to determine whether the interval between the arrival of first responder/defibrillators and paramedic advanced life support (ALS) interventions is associated with outcome. Methods: We carried out a prospective observational study of adults in out-of-hospital cardiac arrest treated by both first responders and paramedics in an urban emergency medical services system between July 15, 1992, and May 27, 1993 (N=544). Results: The gap between first-responder and medic arrival was short (3.2 minutes); medics arrived before first-responder shock in 22% of ventricular fibrillation (VF) cases. Just 10% of patients had a pulse when medics arrived, but the presence of pulse on medic arrival was a powerful predictor of hospital discharge (odds ratio [OR], 20.5; sensitivity, 39%; specificity, 98%; positive predictive value, 55%; negative predictive value, 97%) or a Cerebral Performance Category score on discharge of 1 or 2 (OR, 2.9). No response or individual ALS treatment interval was related to outcome, including the interval from first-responder to medic arrival. ALS interventions by medics were associated with poorer outcomes; even the need for nothing more than additional defibrillation by medics decreased the survival rate of VF patients threefold. By contrast, bystander CPR improved survival more than fourfold and early defibrillation of VF by first responders more than ninefold. Ninety-one percent of all patients discharged from the hospital who received only minimal ALS other than intubation had good neurologic outcome and longer survival after discharge. Half the total survivors of VF arrest (and 59% of all arrest survivors) were resuscitated by medics with aggressive ALS measures, but 80% had very poor neurologic outcomes and 50% died within a year of hospital discharge. Even the need for only additional defibrillation by medics worsened neurologic outcome by a factor of 2.8. Conclusion: Faster response by medics, or any individual ALS intervention other than first-responder defibrillation, demonstrated no benefit in this urban population with short intervals between responder arrivals. Aggressive ALS increased the number of survivors but also decreased their neurologic quality. The benefit of rapid ALS backup to first responder/defibrillators needs further study in other systems. System performance cannot be judged without knowledge of neurologic outcome. [Callaham M, Madsen CD: Relationship of timeliness of paramedic advanced life support interventions to outcome in out-of-hospital cardiac arrest treated by first responders with defibrillators. Ann Emerg Med May 1996;27:638-648.]

Resuscitation training: a time for reassessment.

The goal of resuscitation education is to impart the knowledge and skills necessary to successfully resuscitate a victim of cardiopulmonary arrest. This goal can be accomplished only if the interactions among the instructor, learner, and curriculum are optimized. Instructors must have a clear understanding of educational theory and a thorough grasp of the program materials. Learners must be motivated and committed to developing and maintaining a high level of competence. The in-hospital chain of survival for the resuscitation response system must be reorganized to include determination of the appropriateness of resuscitation and provision of first-responder defibrillation capability. Using creativity and flexibility to meet these goals, nurses can improve the practice and potential outcome of resuscitation.

Relationship of Timeliness of Paramedic Advanced Life Support Interventions to Outcome in Out-of-Hospital Cardiac Arrest Treated by First Responders With Defibrillators

Study objective: We sought to determine whether the interval between the arrival of first responder/defibrillators and paramedic advanced life support (ALS) interventions is associated with outcome. Methods: We carried out a prospective observational study of adults in out-of-hospital cardiac arrest treated by both first responders and paramedics in an urban emergency medical services system between July 15, 1992, and May 27, 1993 (N=544). Results: The gap between first-responder and medic arrival was short (3.2 minutes); medics arrived before first-responder shock in 22% of ventricular fibrillation (VF) cases. Just 10% of patients had a pulse when medics arrived, but the presence of pulse on medic arrival was a powerful predictor of hospital discharge (odds ratio [OR], 20.5; sensitivity, 39%; specificity, 98%; positive predictive value, 55%; negative predictive value, 97%) or a Cerebral Performance Category score on discharge of 1 or 2 (OR, 2.9). No response or individual ALS treatment interval was related to outcome, including the interval from first-responder to medic arrival. ALS interventions by medics were associated with poorer outcomes; even the need for nothing more than additional defibrillation by medics decreased the survival rate of VF patients threefold. By contrast, bystander CPR improved survival more than fourfold and early defibrillation of VF by first responders more than ninefold. Ninety-one percent of all patients discharged from the hospital who received only minimal ALS other than intubation had good neurologic outcome and longer survival after discharge. Half the total survivors of VF arrest (and 59% of all arrest survivors) were resuscitated by medics with aggressive ALS measures, but 80% had very poor neurologic outcomes and 50% died within a year of hospital discharge. Even the need for only additional defibrillation by medics worsened neurologic outcome by a factor of 2.8. Conclusion: Faster response by medics, or any individual ALS intervention other than first-responder defibrillation, demonstrated no benefit in this urban population with short intervals between responder arrivals. Aggressive ALS increased the number of survivors but also decreased their neurologic quality. The benefit of rapid ALS backup to first responder/defibrillators needs further study in other systems. System performance cannot be judged without knowledge of neurologic outcome. [Callaham M, Madsen CD: Relationship of timeliness of paramedic advanced life support interventions to outcome in out-of-hospital cardiac arrest treated by first responders with defibrillators. Ann Emerg Med May 1996;27:638-648.]

Impact of first-responder defibrillation in an urban emergency medical services system: Kellermann AL, Hackman BB, Somes G, et al JAMA 270:1708–1713 Oct 1993

Impact of first-responder defibrillation in an urban emergency medical services system: Kellermann AL, Hackman BB, Somes G, et al JAMA 270:1708–1713 Oct 1993

The Impact of First-Responder Defibrillation

To the Editor. —We applaud the efforts of Kellermann et al 1 to elucidate the relative efficacy of first-response defibrillation on survival after out-of-hospital cardiac arrest. They have used an elegant method to study a difficult issue. Nevertheless, we would like to raise a few concerns about their study. First, the low percentage of patients in the defibrillator arm of the study actually receiving automatic defibrillation may bias the study toward finding no significant difference in survival between groups. The patients receiving automatic defibrillation had a statistically significant slower paramedic response time than those not receiving it within the treatment arm. The lack of benefit from first-responder defibrillation in Memphis, Tenn, may then reflect the negative effect of longer paramedic response times rather than inefficacy of early defibrillation. Alternatively, it may reflect the fact that firefighters clearly arrived first only 50% of the time because of the very rapid response

Prehospital cardiac arrest treated by urban first-responders: Profile of patient response and prediction of outcome by ventricular fibrillation waveform

To determine the speed and characteristics of patient response to urban first-responder defibrillation and to determine whether amplitude of ventricular fibrillation (VF) can predict outcome in these patients. All adult patients in prehospital VF treated by fire department first-responders (265). A prospective observational study occurring between February 1, 1989, and January 1, 1991. Patients were defibrillated according to advanced cardiac life support and first-responder protocols. ECG and time data were recorded digitally. Sixty-five percent of patients converted from VF to a more stable rhythm at least once during first-responder monitoring. Fifty-four percent of converted patients refibrillated at least once, and 42% of all stable conversions occurred after at least one episode of refibrillation. Seventy percent of all refibrillations occurred less than six minutes after the defibrillator was turned on, and 23% occurred after more than ten minutes. The proportion of stable conversions decreased from 30% on first conversion to 2% on fourth conversion. With each successive conversion the interval to refibrillation grew shorter, and development of a pulse or blood pressure became less likely. Presence of blood pressure or pulse after conversion had a sensitivity for hospital discharge of 54% and a specificity of 98%. Maximum VF amplitude before countershock was highly predictive of postshock rhythm, stable conversion in the field, time interval before refibrillation, inpatient admission, and hospital discharge. VF amplitude was unrelated to response interval or interval to defibrillation but was positively related to bystander CPR. Logistic regression identified VF amplitude as the most important predictor of hospital discharge; traditional variables such as response interval and bystander CPR were not predictive once amplitude had been accounted for. Changes in VF amplitude during the course of resuscitation efforts were frequent and also predictive of outcome. Patients in VF who were treated by early countershock refibrillated much more frequently than previously reported. Refibrillations occur both early and late. Initial VF maximum amplitude is strongly predictive of outcome. Future reports of VF cardiac arrest should control for this previously neglected variable. Increased amplitude of VF during repeated refibrillation episodes is associated with increased hospital discharge, so future studies of advanced cardiac life support interventions should explore changes in VF amplitude as an outcome variable.

Impact of First-Responder Defibrillation in an Urban Emergency Medical Services System

Objective. —To evaluate the impact of adding first-responder defibrillation by firefighters to an existing advanced life-support emergency medical services system. Design. —Nonrandomized, controlled clinical trial with periodic crossover. Setting. —Memphis, Tenn, a city of 610337 people, which is served by a fire department-based emergency medical services system. All city ambulances provide advanced life support. Patients. —Adult victims of out-of-hospital cardiac arrest due to heart disease. Intervention. —Twenty of 40 participating engine companies were equipped with an automated external defibrillator and ordered to apply it immediately in all cases of cardiac arrest. The other 20 companies were ordered to start cardiopulmonary resuscitation (CPR) immediately and wait for paramedics to arrive. Every 75 days, group roles were reversed. Care otherwise proceeded according to 1986 American Heart Association guidelines. Main Outcome Measures. —Return of spontaneous circulation in the field, to hospital admission, to hospital discharge, and neurological status at discharge. Results. —During the 39-month study interval, 879 patients were treated by a project engine company. Four hundred thirty-one (49%) of these were found in ventricular fibrillation. Bystander CPR was started in only 12% of cases. Overall, firefighters reached the scene a mean of 2.5 minutes faster than simultaneously dispatched paramedics. Although our automated external defibrillators proved to be reliable and efficacious for terminating ventricular fibrillation and pulseless ventricular tachycardia, patients treated by an automated external defibrillator— equipped engine company were no more likely than CPR-treated controls to be resuscitated (32% vs 34%, respectively), to survive to hospital admission (31% vs 29%), or to survive to hospital discharge (14% vs 10%). Neurological outcomes were also similar in the two treatment groups. Conclusions. —In a fast-response, urban emergency medical services system served by paramedics, the impact of adding first-responder defibrillation appears to be small. Early defibrillation alone cannot overcome low community rates of bystander CPR. Careful attention to every link in the chain of survival is needed to achieve optimal rates of after cardiac arrest. (JAMA. 1993;270:1708-1713)