Automated External Defibrillator Program Does Not Impair Cardiopulmonary Resuscitation Initiation in the Public Access Defibrillation Trial

Objectives: To evaluate whether automated external defibrillator (AED) training and AED availability affected the response of volunteer rescuers and performance of cardiopulmonary resuscitation (CPR) in presumed out‐of‐hospital cardiac arrest (OOH‐CA) during the multicenter Public Access Defibrillation Trial. Methods: The Public Access Defibrillation Trial recruited 1,260 facilities in 24 North American regional sites to participate in a trial addressing survival from OOH‐CA when AED training and availability were added to a volunteer‐based emergency response team. Volunteers at each facility were trained to perform either CPR alone (CPR) or CPR in conjunction with AED use (CPR+AED) according to randomized assignments. This study reports the frequency of response and initiation of CPR actions (chest compressions and/or ventilations) by volunteers in the CPR and CPR+AED study groups. Results: A total of 314 presumed OOH‐CA episodes occurred in CPR facilities, and 308 occurred in CPR+AED facilities. The volunteers were matched well for age, gender, and other features. Overall, ventilations (23.1% vs. 13.1%), chest compressions (24.4% vs. 12.1%), and both actions (19.8% vs. 10.5%; all p < 0.05) were more commonly performed in OOH‐CA cases in the CPR+AED group. However, when only OOH‐CA cases with volunteers responding were analyzed, the rates of CPR actions were similar. In the subgroup of CPR+AED cases with a responding volunteer, the AED was turned on for only 47% of cases. Volunteers initiated a CPR action more commonly when the AED was turned on (60.7% vs. 39.3%; p = 0.003). Conclusions: In the Public Access Defibrillation Trial, rates of CPR actions for presumed OOH‐CA victims were low but similar for CPR and CPR+AED responding volunteer rescuers. Factors associated with volunteer response, CPR action initiation, and AED activation warrant further investigation.     

How Well are Cardiopulmonary Resuscitation and Automated External Defibrillator Skills Retained over Time? Results from the Public Access Defibrillation (PAD) Trial

Background: The current standard for cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED) retraining for laypersons is a four‐hour course every two years. Others have documented substantial skill deterioration during this time period. Objectives: To evaluate 1) the retention of core CPR and AED skills among volunteer laypersons and 2) the time required to retrain laypersons to proficiency as a function of time since initial training. Methods: This was an observational follow‐up study evaluating CPR and AED skill retention and testing/retraining time up through 17 months after initial training. The study took place at 1,260 facilities recruited by 24 North American clinical research centers, and included 6,182 volunteer laypersons participating in the Public Access Defibrillation (PAD) Trial. Training to proficiency in either CPR only (N= 2,426) or CPR+AED (N= 3,756) was followed by testing/retraining provided three to 17 months later. Retraining was done in brief, one‐on‐one, individualized, interactive sessions. The outcome studied was instructors' global assessments of performance of CPR and AED skill adequacy, i.e., whether CPR actions would likely result in perfusion (yes/no) and whether AED actions would result in a shock through the heart (yes/no). Results: For global CPR performance, 79%, 73%, and 71% of volunteers tested for the first time since initial training three to five, six to 11, and 12 to 17 months after initial training, respectively, were judged by their instructors as having adequate performance (p < 0.001, chi‐square for linear trend). For global AED performance, 91%, 86%, and 84% of volunteers, respectively, were judged as having adequate performance (p < 0.001). The mean (± standard deviation) times required to test and retrain volunteers to proficiency were 5.7 (± 4.0) minutes for CPR skills and 7.7 (± 4.6) minutes for CPR+AED skills. Conclusions: Among PAD Trial volunteer laypersons participating in a simulated resuscitation, the proportions of volunteers judged by instructors to have adequate CPR and AED skills demonstrated small declines associated with longer intervals between initial training and subsequent testing. However, based on instructors' judgment, large majorities of volunteers still retained both CPR and AED core skills through 17 months after initial training. Furthermore, individual testing and retraining for CPR and AED skills were usually accomplished in less than 10 minutes per volunteer. Additional research is essential to identify training and evaluation techniques that predict adequate CPR and AED skill performance of laypersons when applied to an actual cardiac arrest.     

Public-access defibrillation: Where do we place the aeds?

Background. Many prehospital cardiac arrests occur in public places. Even the best EMS systems have a finite response time. Therefore, it has been recommended that automated external defibrillators (AEDs) be placed in public areas for immediate access by trained members of the general public. Objective. To determine the locations of multiple cardiac arrests in order to plan for placement of public-access AEDs. Methods. Retrospective review of all primary cardiac arrests in calendar year 1997. Cardiac arrests in which resuscitation was not attempted (DOA), traumatic cases, pediatric cases, and those due to “other” causes were excluded. Location of the cardiac arrest was obtained from the ambulance run ticket. The EMS system is an urban, Midwestern, all-ALS, public-utility model system with fire department first re-sponders that transports approximately 58,000 patients annually. Results. There was scene response to 922 cardiac arrests. 377 DOAs and 219 nonprimary cardiac arrests were excluded. There were 326 primary cardiac arrests. Sixteen locations had more than one cardiac arrest: ll locations had two cardiac arrests, four locations had three cardiac arrests, and one location had four cardiac arrests. The airport, an airline overhaul facility, a casino, and two hotels each had two cardiac arrests; the other Iocations of multiple cardiac arrests were in nursing homes. The Professional sports stadiums had no cardiac arrests. Conclusions. Since very few locations had more than one cardiac arrest, it may be difficult to identify high-yield public places in which to place an AED. Nursing homes may want to consider AED availability.     

The location and incidence of out-of-hospital cardiac arrest in Georgia: : Implications for placement of automated external defibrillators

Objective

Prior studies of automated external defrillator placement strategies for public access defibrillation (PAD) have addressed only the venue of out-of-hospital cardiac arrest (OOHCA) in large urban areas. This study evaluates the relationship between population density and the incidence and location of OOHCA.

Methods

This study was a retrospective analysis of 624,199 Georgia state emergency medical services patient care reports (PCRs) in 2000. The PCR categorized these cardiac arrests by county into 12 location options. Counties were divided into population densities of <100, 100-400, 400-1,000, and >1,000 persons per square mile. The incidence of cardiac arrest for each location type was calculated for each population density group.

Results

The <100 density group had only 21.77% of the state's population but 30.96% of the state's cardiac arrests, whereas the >1,000 density group had 35.46% of the population but only 23.55% of the cardiac arrests (p<0.0001). The relative risk (95% confidence interval) for OOHCA in the <100 density group compared with the >1,000 density group was 2.14 (2.00, 2.29). The percentage of OOHCAs that occurred in the home for each population density group was: <100 persons per square mile, (67.67%); 100-400 persons per square mile, (68.83%); 400-1,000 persons per square mile, (65.75%); and >1,000 persons per square mile (62.09%) (p = 0.0001).

Conclusions

There are variations in incidence and location of OOHCA based on population density in Georgia. As population density increases, the incidence percentage of OOHCAs decreases. However, as population density increases, there is an increase in the percentage of cardiac arrests occurring outside the home, where more OOHCAs could potentially benefit from PAD.     

Validation of a Predictive Model for Automated External Defibrillator Placement in Rural America

Objective. The development of Automated External Defibrillators (AEDs) to treat out-of-hospital cardiac arrest (OOHCA) has greatly expanded the availability of life saving defibrillatory shocks in various settings. However, placement of AEDs in rural areas remains perplexing since OOHCAs are rare andunpredictable. We set out to develop a cost-effective rural AED placement model andto test the validity of the resulting model using OOHCAs attended by EMS. Methods. Design: A population-based cross-sectional study. Analytic Plan: An exhaustive literature search was conducted to identify community attributes correlated with successful placement of AEDs in rural regions. Identified attributes were characterized using U.S. Census andCDC heart disease mortality data to estimate the potential risk for AED use andapplied this estimate to rural census tracts in all 50 states. Based upon risk, AEDS were assigned to each tract using a first responder model andcost effectiveness was assessed. Using Utah State EMS data, the predicted placement of AEDs in each tract was validated using the actual number of OOHCAs attended by EMS. Results. A total of 14,586 rural census tracts in 50 U.S. states were evaluated. On average, 2,600 AEDs were situated within each state. AED placement in rural areas proved as cost effective as health screening programs. In Utah, predicted AED placement correlated with the frequency of OOHCAs attended by EMS personnel (ρ = 0.55, p < 0.001). Conclusions. The resulting model illustrates one potential way to determine the most beneficial location for rural AED placement.     

Public Access Defibrillation: Great benefit and potential but infrequently used

BackgroundIn Copenhagen, a volunteer-based Automated External Defibrillator (AED) network provides a unique opportunity to assess AED use.We aimed to determine the proportion of Out-of-Hospital Cardiac Arrest (OHCA) where an AED was applied before arrival of the ambulance, and the proportion of OHCA-cases where an accessible AED was located within 100 m. In addition, we assessed 30-day survival.MethodsUsing data from the Mobile Emergency Care Unit and the Danish Cardiac Arrest Registry, we identified 521 patients with OHCA between October 1, 2011 and September 31, 2013 in Copenhagen, Denmark.ResultsAn AED was applied in 20 cases (3.8%, 95% CI [2.4 to 5.9]). Irrespective of AED accessibility, an AED was located within 100 m of a cardiac arrest in 23.4% (n = 102, 95% CI [19.5 to 27.7]) of all OHCAs. However, at the time of OHCA, an AED was located within 100 m and accessible in only 15.1% (n = 66, 95% CI [11.9 to 18.9]) of all cases.The 30-day survival for OHCA with an initial shockable rhythm was 64% for patients where an AED was applied prior to ambulance arrival and 47% for patients where an AED was not applied.ConclusionsWe found that 3.8% of all OHCAs had an AED applied prior to ambulance arrival, but 15.1% of all OHCAs occurred within 100 m of an accessible AED. This indicates the potential of utilising AED networks by improving strategies for AED accessibility and referring bystanders of OHCA to existing AEDs.     

Double Sequential External Defibrillation and Survival from Out-of-Hospital Cardiac Arrest: A Case Report

Background: Patients who present in ventricular fibrillation are typically treated with cardiopulmonary resuscitation (CPR), epinephrine, antiarrhythmic medications, and defibrillation. Although these therapies have shown to be effective, some patients remain in a shockable rhythm. Double sequential external defibrillation has been described as a viable option for patients in refractory ventricular fibrillation. Objective: To describe the innovative use of two defibrillators used to deliver double sequential external defibrillation by paramedics in a case of refractory ventricular fibrillation resulting in prehospital return of spontaneous circulation and survival to hospital discharge with good neurologic function. Case: A 28-year-old female sustained a witnessed out-of-hospital cardiac arrest (OHCA). Bystander CPR was performed by her husband followed by paramedics providing high-quality CPR, antiarrhythmic medication, and 6 biphasic defibrillations using standard energy levels. Double sequential external defibrillation was applied and a return of spontaneous circulation was attained on scene and maintained through to arrival to the emergency department. Following admission to hospital the patient was diagnosed with long QT syndrome. An implantable cardioverter defibrillator was placed and the patient was discharged with a Cerebral Performance Category of 2 as well as a modified Rankin Scale of 2 after an 18-day hospital stay. The patient's functional status continued to improve post discharge. Conclusion: The addition of double sequential external defibrillation as part of a well-organized resuscitation effort may be a valid treatment option for OHCA patients who present in refractory ventricular fibrillation.     

Biphasic Defibrillation Does not Improve Outcomes Compared to Monophasic Defibrillation in Out-of-Hospital Cardiac Arrest

Study Objective. To compare the outcomes of out-of hospital cardiac arrest (OHCA) victims treated with monophasic truncated exponential (MTE) versus biphasic truncated exponential (BTE) defibrillation in an urban EMS system. Methods. We conducted a retrospective review of electronic prehospital andhospital records for victims of OHCA between August 2000 andJuly 2004, including two years before andafter implementation of biphasic defibrillators by the Fresno County EMS agency. Main outcome measures included: return of spontaneous circulation (ROSC), number of defibrillations required for ROSC, survival to hospital discharge, anddischarge to home versus an extended care facility. Results. There were 485 cases of cardiac arrest included. Baseline characteristics between the monophasic andbiphasic groups were similar. ROSC was achieved in 77 (30.6%, 95% CI 25.2–36.5%) of 252 patients in the monophasic group, andin 70 (30.0% 95% CI 24.5–36.2%) of 233 in the biphasic group (p =. 92). Survival to hospital discharge was 12.3% (95% CI 8.8–17%) for monophasic and10.3% (95% CI 7.0–14.9%) for biphasic (p =. 57). Discharge to home was accomplished in 20 (7.9%, 95% CI 5.1–12.0%) of the monophasic, andin 15 (6.4%, 95% CI 3.9–10.4%) of the biphasic group (p =. 60). More defibrillations were required to achieve ROSC (3.5 vs. 2.6, p =. 015) in the monophasic group. Conclusions. We found no difference in ROSC or survival to hospital discharge between MTE andBTE defibrillation in the treatment of OHCA, although fewer defibrillations were required to achieve ROSC in those treated with biphasic defibrillation.     

基层军医除颤技能掌握现状及自动体外除颤仪培训的效果

目的 调查基层军医的除颤技能掌握现状,并通过自动体外除颤仪(automated external defibrillator,AED)培训,增强其除颤能力和自信心.方法 便利抽样选择参加第二军医大学全科医学培训的基层军医224名,对其进行AED培训,并在培训前后填答相关调查问卷.结果 基层军医培训后首次除颤时间、自信心水平、电极片放置准确率、除颤前确保所有人离开患者及除颤后立即重新开始心肺复苏的实施率均优于培训前,差异有统计学意义(均P＜0.01).结论 基层军医缺乏实施除颤的经历且很少接受除颤培训,除颤能力和自信心不足;考虑到AED的优势,应为基层部队更多地配置AED以保证早期除颤的实施,同时AED培训可以有效提升基层军医的除颤能力和自信心.     

Ventricular Fibrillation in Pediatric Cardiac Arrest

Objectives: After activating 9‐1‐1 for out‐of‐hospital cardiac arrest (CA), guidelines for children 1 year and older have evolved to include immediate automated external defibrillator (AED) use for witnessed arrest, and two minutes of cardiopulmonary resuscitation (CPR) followed by AED use for unwitnessed arrests. The best approach to resuscitation in a two‐tiered emergency medical services (EMS) system depends in part on how likely the patient is to present with ventricular fibrillation (VF). Therefore, the authors evaluated the frequency of VF with respect to age and other characteristics to further elucidate the role of the AED among pediatric CAs. Methods: The investigation was a retrospective cohort study of EMS‐treated, nontraumatic, out‐of‐hospital CA among persons aged 1–18 years in King County, Washington, between April 1, 1976, and December 31, 2003. The primary goal was to identify the proportion of patients presenting to EMS in VF, according to age. The association between other characteristics and the likelihood of VF was also evaluated. Finally, hospital survival according to cardiac rhythm at EMS arrival was evaluated. Results: Ventricular fibrillation was the presenting rhythm in 17.6% of cases (48/272). The proportion presenting with VF was 7.6% (10/131) among children aged 1–7 years and 27.0% (38/141) among children aged 8–18 years (p < 0.001). In multivariable models, VF was independently associated with age 8 years and older compared with 1–7 years (odds ratio, 3.19; 95% confidence interval [CI] = 1.46 to 6.97), witnessed arrest (odds ratio, 3.33; 95% CI = 1.63 to 6.82), and cardiac etiology (odds ratio, 2.89; 95% CI = 1.32 to 6.34). Survival was 31.3% (15/48) for VF and 10.7% (24/224) for nonshockable rhythm CAs. Conclusions: The proportion of children aged younger than 8 years presenting with VF is low compared with older children. The greatest increase in VF proportion occurs in children older than 12 years. Based on these results, the best approach for initial EMS resuscitation in a two‐tiered EMS system, CPR versus AED use, is uncertain among younger children. Inclusion of witness status into the decision process for younger children may more efficiently allocate AED use, a finding in accordance with 2005 guidelines.     

Effectiveness of Prehospital Dual Sequential Defibrillation for Refractory Ventricular Fibrillation and Ventricular Tachycardia Cardiac Arrest

Objective: Dual sequential defibrillation (DSD) — successive defibrillations with two defibrillators — offers a novel approach to refractory ventricular fibrillation (RVF) and tachycardia (VF/VT). While associated with rescue shock success, the effect of DSD upon out-of-hospital cardiac arrest (OHCA) is unknown. We evaluated the association of DSD with survival after refractory VF/VT OHCA. Methods: We used data from a large metropolitan fire-based EMS service. We included all adult OHCA during 2013–2016 with ≥3 standard defibrillations. Physicians authorized subsequent DSD use by two separate defibrillators (PhysioControl LIFEPAK® 12/15) with pads placed anterior-lateral and anterior-posterior. Evaluated outcomes included return of spontaneous circulation (ROSC), survival to hospital admission, survival to 72?hours, and survival to hospital discharge. Using multivariable logistic regression, we evaluated the association between defibrillation type and OHCA outcomes, adjusting for patient demographics and event characteristics. Results: We included 310 patients in the analysis, 71 patients receiving DSD and 239 receiving conventional defibrillation. Patient demographics and event characteristics were similar between both groups. ROSC was lower for DSD than standard defibrillation: 39.4% vs. 60.3%, adjusted OR 0.46 (95% CI: 0.25–0.87). There were no differences in survival to hospital admission (35.2% vs. 49.2%, adjusted OR 0.57 [95% CI: 0.30–1.08]), survival to 72?hours (21.4% vs. 32.3%, adjusted OR 0.52 [95% CI: 0.26–1.10]), or survival to hospital discharge (14.3% vs. 20.9%, adjusted OR 0.63 [95% CI: 0.27–1.45]). Conclusions: Compared with conventional defibrillation, DSD was associated with lower odds of prehospital ROSC. Defibrillation type was not associated with other OHCA endpoints. DSD may not be beneficial in refractory VF/VT OHCA.     

The Effect of Multiple Shocks on Canine Cardiac Defibrillation

FLAKER, G., ET AL.: The Effect of Multiple Shocks on Canine Cardiac Defibrillation. To determine if multiple shocks adversely affect the success of later shocks compared with early shocks, we analyzed the success rates of initial shocks (defibrillation attempts 1–5), first half shocks (defibrillation attempts 1–20) and second half shocks [defibrillation attempts 21–40) in a canine model. Epicardial patches were placed on the right and left ventricle in 28 dogs. Ventricular fibrillation was induced by a 60-Hz shock. After 30 seconds, defibrillation was attempted using 7, 12, 13, or 18 joules with either a uniphasic or biphasic rectangular waveform. The uniphasic waveform was 5 msec in duration; the biphasic waveform was 10 msec, with the lagging 5-msec pulse one-half the amplitude of the leading 5-msec pulse. For uniphasic shocks, the right ventricular patch was positive; for biphasic shocks, the right ventricular patch was positive during the leading 5 msec of the shock and negative during the lagging milliseconds. A total of 960 fibrillation episodes were evaluated; no dog was involved in more than 40 fibrillation episodes. The success rates of defibrillation attempts 1–5, defibrillation attempts 1–20, and defibrillation attempts 21–40 were similar at 12, 13, and 18 joules. This information supports the continued use of up to 40 fibrillation trials in canine cardiac defibrillation. However, at 7 joules defibrillation attempts 21–40 were more successful than defibrillation attempts 1–5, and 1–20. With our methodology, these data are consistent with the hypothesis that low energy shocks create a "sensitizing" effect on cardiac tissue, allowing more successful defibrillation with repeated shocks.     

Double Sequential Defibrillation for Refractory Ventricular Fibrillation: A Case Report

Abstract

A 40-year-old male struck his chest against a pole during a basketball game and had sudden out-of-hospital cardiac arrest. After bystander cardiopulmonary resuscitation, fire and emergency medical services personnel provided six defibrillation attempts prior to emergency department arrival. A 7th attempt in the emergency department using a different vector was unsuccessful. On the 8th attempt, using a second defibrillator with defibrillator pads placed adjacent to the primary set of defibrillator pads, two shocks were administered in near simultaneous fashion. The double sequential defibrillation was successful and the patient had return of spontaneous circulation at the next pulse check. He recovered in the intensive care unit, was discharged home 1 month later, and continues to follow up in clinic over 1 year later with a Cerebral Performance Category score of 1 (short-term memory deficits).