Quality of basic life support when using different commercially available public access defibrillators

The impact on users of an unfamiliar AED following a recent training experience: A randomized cross over simulation study

Objective

This study examined the impact of prior familiarity with automated external defibrillator (AED) models on the time of defibrillation and the emotional experiences of laypersons.

Methods

We conducted a randomized cross over simulation study with 123 participants to assess their reactions to both familiar and unfamiliar AED models. The time to first defibrillation was measured using three different AED training models, two of which were previously unknown to the participants. Additionally, semi-structured interviews were held with the participants to gather further insights.

Results

Participants took longer to initiate defibrillation with unfamiliar (M = 34 s) AEDs compared to familiar (M = 27 s) ones. This delay was accompanied by feelings of confusion, nervousness, and anxiety. Factors such as the design of the AED covers, electrodes, and buttons were identified as sources of confusion. Nonetheless, clear instructions and similarities between devices helped facilitate their use.

Conclusion

The findings suggest that AED design and familiarity with different AED designs may affect performance by laypersons. To improve user confidence, it would be useful to familiarize users with a variety of AED models as part of training initiatives. Understanding the impact of AED familiarity on rescuer's response can guide CPR training strategies and improve outcomes for OHCA. As more AED models become available to the public, the user-friendliness of AEDs may also be improved. It is beneficial for AED manufacturers to consider the results of research when developing new models.

An effort to reduce chest compression pauses during automated external defibrillator use among laypeople: A randomized partially blinded controlled trial

Aim

To implement small methodological changes in basic life support (BLS) training to reduce unnecessary pauses during automated external defibrillator (AED) use.

Methods

One hundred and two university students with no BLS knowledge were randomly allocated into three groups (control and 2 experimental groups). Both experimental groups received a two-hour BLS training. While the contents were identical in both groups, in one of them the reduction of no-flow time was focused on (focused no-flow group). The control group did not receive any training. Finally, all of them were evaluated in the same out-of-hospital cardiac arrest simulated scenario. The primary endpoint was the compression fraction.

Results

Results from 78 participants were analysed (control group: 19; traditional group: 30; focused no-flow group: 29). The focused no-flow group achieved higher percentages of compression fraction (median: 56.0, interquartile rank (IQR): 53.5-58.5) than the traditional group (44.0, IQR: 42.0-47.0) and control group (52.0, IQR: 43.0-58.0) in the complete scenario. Participants from the control group performed compression-only cardiopulmonary resuscitation (CPR), while the other groups performed compression-ventilation CPR. CPR fraction was calculated, showing the fraction of time in which the participants were performing resuscitation manoeuvres. In this case, the focused no-flow group reached higher percentages of CPR fraction (77.6, IQR: 74.4-82.4) than the traditional group (61.9, IQR: 59.3-68.1) and the control group (52.0, IQR: 43.0-58.0).

Conclusions

Laypeople having automated external defibrillation training focused on acting in anticipation of the AED prompts contributed to a reduction in chest compression pauses during an OHCA simulated scenario.

Differences in Automated External Defibrillator Types in Out-of-Hospital Cardiac Arrest Treated by Police First Responders

Background: Police first responder systems also including automated external defibrillation (AED) has in the past shown considerable impact on favourable outcomes after out-of-hospital cardiac arrest (OHCA). While short hands-off times in chest compressions are known to be beneficial, various AED models use different algorithms, inducing longer or shorter durations of crucial timeframes along basic life support (BLS). Yet, data on details of these differences, and also of their potential impact on clinical outcomes are scarce. Methods: For this retrospective observational study, patients with OHCA of presumed cardiac origin and initially shockable rhythm treated by police first responders in Vienna, Austria, between 01/2013 and 12/2021 were included. Data from the Viennese Cardiac Arrest Registry and AED files were extracted, and exact timeframes were analyzed. Results: There were no significant differences in the 350 eligible cases in demographics, return of spontaneous circulation, 30-day survival, or favourable neurological outcome between the used AED types. However, the Philips HS1 and -FrX AEDs showed immediate rhythm analysis after electrode placement (0 [0-1] s) and almost no shock loading time (0 [0-1] s), as opposed to the LP CR Plus (3 [0-4] and 6 [6-6] s, respectively) and LP 1000 (3 [2-10] and 6 [5-7] s, respectively). On the other hand, the HS1 and -FrX had longer analysis times of 12 [12-16] and 12 [11-18] s than the LP CR Plus (5 [5-6] s) and LP 1000 (6 [5-8] s). The duration from when the AED was turned on until the first defibrillation were 45 [28-61] s (Philips FrX), 59 [28-81] s (LP 1000), 59 [50-97] s (HS1), and 69 [55-85] s (LP CR Plus). Conclusion: In a retrospective analysis of OHCA-cases treated by police first responders, we could not find significant differences in clinical patient outcomes concerning the respective used AED model. However, various differences in time durations (e.g., electrode placement to rhythm analysis, analysis duration, or AED turned on until first defibrillation) along the BLS algorithm were seen. This opens up the question of AED-adaptations and tailored training methods for professional first responders.

Evaluation of automated external defibrillator designed for people in dogs

OBJECTIVE

To determine if human automated external defibrillators (AEDs) could successfully record cardiac electrical activity in dogs, make appropriate recommendations regarding shock delivery, and characterize skin preparation required for a readable ECG based on dog haircoat characteristics.

DESIGN

Prospective study of AED use in dogs conducted between January and March 2021.

SETTING

University teaching hospital.

ANIMALS

Three groups of client-owned dogs were evaluated. Group 1 consisted of 23 healthy dogs with sinus rhythms, group 2 consisted of 9 dogs with documented cardiac arrhythmias, and group 3 consisted of 9 dogs receiving CPR following naturally occurring cardiopulmonary arrest.

MATERIALS AND METHODS

Haircoat characteristics and clipping or ECG paste required to obtain a readable ECG were recorded. The time interval from a readable ECG by the investigator until AED shock advisement was measured. Correctness of shock advice was recorded. Analyses were performed using commercial statistical software. P-values <0.05 were considered significant.

RESULTS

The attending veterinarian judged the ECG on the AED to be readable in all dogs. Time to shock advisement in all dogs was median 18 (range: 7-180) seconds. Dogs with heavy, long, or double haircoats required clipping in 24 of 27 (89%) cases to obtain a readable ECG. ECG paste on the AED pad was required in 36 of 40 dogs (90%) in order to obtain a readable ECG. The AED advice for delivery of shock was appropriate in 51 of 52 (98%) queries of the machine across all groups.

CONCLUSIONS

Human AEDs can successfully record cardiac electrical activity in dogs. AEDs appropriately recommend delivery of a shock most times, contingent on skin preparation. Dogs with double, long, or heavy haircoats should be clipped prior to pad application. ECG paste will aid AED reading in all haircoat types. Further investigation is warranted into AED use in dogs, particularly in general practices.

[AED drones on the rise? : Use of drones to improve public access defibrillation]

BACKGROUND

The poor availability of automatic external defibrillators (AED) and the modest knowledge of lay persons in handling these devices has led to an insufficient spread of public access defibrillation in Germany.

OBJECTIVE

This article examines whether the automated deployment of AED drones to out-of-hospital cardiac arrest can help to remedy this situation.

METHODS

Narrative literature review, evaluation of statistics, analysis of relevant media reports, and discussion of key research.

RESULTS

The present investigations are mainly located in the experimental field and demonstrate the feasibility and safety of drone use, as well as shorter times to first defibrillation, which is confirmed by initial clinical studies. Mathematical models also indicate cost-effectiveness of airborne AED delivery compared to ground dispatch. Integration into the chain of survival appears to be possible but adaptations to existing emergency medical service structures and close cooperation with regional first responder and AED schemes as well as local authorities is required to optimise patient benefit and efficiency.

CONCLUSION

The use of AED drones could probably contribute to improving public access defibrillation in Germany. This applies to both rural and urban regions. The technological requirements are met but flight regulations still have to be amended. In order to explore the full potential of this novel technology, further field trials are required to achieve smooth integration into existing emergency medical services.

[Effects of automated external defibrillators on hands-off intervals in lay rescuers]

Background

Survival chances after out-of-hospital cardiac arrests caused by hyperdynamic electric cardiac rhythms can be significantly improved by early defibrillation with automated external defibrillators (AEDs). As postulated in international guidelines, the resulting hands-off intervals should not exceed 10 s.

Objectives

We investigated delay in onset of chest compressions and the length of hands-off intervals during defibrillation associated with the application of AEDs.

Materials and methods

In a prospective, randomized, single-blinded observational study, the resuscitation efforts by first year medical students were analyzed in different emergency scenarios on manikins. Delay in onset of chest compressions and the length of hands-off intervals between voice prompts from four conventional devices were compared during shockable and nonshockable rhythms. Satisfaction with the device, difficulties with the application, and suggested improvements were assessed by questionnaire.

Results

In a total of 70 applications, the start with thoracic compressions was delayed by a mean of 115 s. On average, the first shock was administered after 125 s in shockable heart rhythms. Perishock pauses of less than 10 s were achieved with none of the tested devices. Hands-off intervals during defibrillation differed significantly between the devices (p < 0.001). Improvements were suggested regarding marking, voice prompts, and electrodes.

Conclusions

Perishock pause of less than 10 s was not achieved with any of the tested devices. Shortened and more precise voice prompts as well as more clearly arranged labeling and layout of pads are needed to simplify application, reduce delayed onset of chest compressions and shorten hands-off intervals.

Effects of an Automated External Defibrillator With Additional Video Instructions on the Quality of Cardiopulmonary Resuscitation

Aim of the Study: The aim was to compare cardiopulmonary resuscitation (CPR) quality of an automated external defibrillator (AED) with and without additional video instruction during basic life support (BLS) by laypersons. Methods: First-year medical students were randomized either to an AED with audio only or audio with additional video instructions during CPR. Each student performed 4 min of single-rescuer chest compression only BLS on a manikin (Ambu Man C, Ballerup, Denmark) using the AED. The primary outcome was the effective compression ratio during this scenario. This combined parameter was used to evaluate the quality of chest compressions by multiplying compressions with correct depth, correct hand position, and complete decompression by flow time. Secondary outcomes were percentages of incomplete decompression and hand position, mean compression rate, time-related parameters, and subjective assessments. Results: Effective compression ratio did not differ between study groups in the overall sample (p = 0.337) or in students with (p = 0.953) or without AED experience (p = 0.278). Additional video instruction led to a higher percentage of incorrect decompressions (p = 0.014). No significant differences could be detected in time-related resuscitation parameters. An additional video was subjectively rated as more supporting (p = 0.001). Conclusions: Audio-video instructions did not significantly improve resuscitation quality in these laypersons despite that it was felt more supportive. An additional video to the verbal AED prompts might lead to cognitive overload. Therefore, future studies might target the influence of the video content and the potential benefits of video instructions in specific populations.

Applying Principles From Aviation Safety Investigations to Root Cause Analysis of a Critical Incident During a Simulated Emergency

STATEMENT

Safety investigations in aviation aim to identify potential root causes. They use structured techniques to analyze information from flight data and cockpit voice recorders. Full-scale medical simulations using audiovisual recordings provide similar possibilities. During a simulated cardiac arrest, an incident related to use of the defibrillator (automated external defibrillator) occurred with emergency medical services (EMS) providers. Treatment interventions and dialogs during the incident were extracted from audiovisual recordings and transferred into a transcript of events.Knowing indicated treatment measures, the team adhered to automated external defibrillator voice prompts rather than follow their own assessment. Cardiopulmonary resuscitation was on hold for 72% of the time. Time to first defibrillation was delayed by 2:17 minutes. Transcript allowed us to identify faulty decision-making, loss of leadership, and automation bias as possible root causes. Use of RCA methodology during medical simulation improves understanding of critical incidents and can contribute to training of EMS personnel and education of instructors.

Analyzing the heart rhythm during chest compressions: Performance and clinical value of a new AED algorithm

PURPOSE

Automated external defibrillators (AED) prompt the rescuer to stop chest compressions (CC) for ECG analysis during out-of-hospital cardiac arrest (OHCA). We assessed the diagnostic accuracy and clinical benefit of a new AED algorithm (cprINSIGHT), which analyzes ECG and impedance signals during CC, allowing rhythm analysis with ongoing chest compressions.

METHODS

Amsterdam Police and Fire Fighters used a conventional AED in 2016-2017 (control) and an AED with cprINSIGHT in 2018-2019 (intervention). In the intervention AED, cprINSIGHT was activated after the first (conventional) analysis. This algorithm classified the rhythm as "shockable" (S) and "non-shockable" (NS), or "pause needed". Sensitivity for S, specificity for NS with 90% lower confidence limit (LCL), chest compression fractions (CCF) and pre-shock pause were compared between control and intervention cases accounting for multiple observations per patient.

RESULTS

Data from 465 control and 425 intervention cases were analyzed. cprINSIGHT reached a decision during CC in 70% of analyses. Sensitivity of the intervention AED was 96%, (LCL 93%) and specificity was 98% (LCL 97%), both not significantly different from control. Intervention cases had a shorter median pre-shock pause compared to control cases (8 s vs 22 s, p < 0.001) and higher median CCF (86% vs 80%, P < 0.001).

CONCLUSION

AEDs with cprINSIGHT analyzed the ECG during chest compressions in 70% of analyses with 96% sensitivity and 98% specificity when it made a S or a NS decision. Compared to conventional AEDs, cprINSIGHT leads to a significantly shorter pre-shock pause and a significant increase in CCF.

Quality of dispatcher-assisted vs. automated external defibrillator-guided cardiopulmonary resuscitation: a randomised simulation trial

BACKGROUND

Quality of hands-only cardiopulmonary resuscitation (CPR) is an important determinant of resuscitation outcome for cardiac arrest patients cared for by lay rescuers. We designed a simulation trial to assess and compare the quality of CPR among untrained lay people under two different scenarios: automated external defibrillator (AED)-guided and dispatcher-assisted CPR.

PATIENTS AND METHODS

A simulation study was performed involving 42 volunteers selected by non-probabilistic sampling. Participants were randomized into two CPR simulation scenarios with a manikin: (A) AED-guided CPR and (T) dispatcher-assisted CPR. The quality of CPR was evaluated by metric monitoring of the chest compressions and timing of actions. Content analysis of the telephone instructions was performed by two independent researchers using a checklist.

RESULTS

CPR was started in 20 of the 21 cases in scenario A and in all cases in scenario T. In total, 12 053 chest compressions were applied, 57.6% corresponding to scenario A. The proportion of compressions that were of an adequate depth was low in both cases, 15.3% in scenario A vs. 31.7% in scenario T (P < 0.001), while complete chest recoil was allowed in 66 and 72% (P < 0.001) of compressions, respectively. The AED advised to shock 91 times, and shocks were delivered in all cases.

CONCLUSIONS

Although guided CPR helps untrained people to initiate resuscitation manoeuvres, the quality of CPR was poor in both groups. Telephone guidance improved the proportion of compressions that achieved adequate chest compression and recoil but did not optimise the compression rate.

Competence-based training needs assessment for basic life support instructors

Basic life support instructors play an important role in the planning, implementation, and evaluation of basic life support education. However, little is known about basic life support instructors' competence. The aim of the present study was to identify basic life support instructors' competence attributes and assess their competence-based training needs according to their expertise. This was a descriptive survey study to identify the educational needs of basic life support instructors using importance and performance analysis. A Web-based survey with a 29 item Competence Importance-Performance scale was undertaken with a convenience sample of 213 Korean instructors. Factor analysis identified several important factors for the competence of instructors: assessment, professional foundations, planning and preparation, educational method and strategies and evaluation. The importance and performance analysis matrix showed that training priorities for novice instructors were communication with learners and instructors, learner motivation, educational design, and qualifications of instructors, whereas checking equipment status and educational environment had the highest training priority for experienced instructors. Assessment was the most important factor in basic life support instructor's competence. A competence-based training program is needed according to basic life support instructors' expertise.

Manual Versus Semiautomatic Rhythm Analysis and Defibrillation for Out-of-Hospital Cardiac Arrest

BACKGROUND

Although manual and semiautomatic external defibrillation (SAED) are commonly used in the management of out-of-hospital cardiac arrest, the optimal strategy is not known. We hypothesized that SAED would reduce the time to first shock and lead to higher rates of cardioversion and survival compared with a manual strategy.

METHODS AND RESULTS

Between July 2005 and June 2015, we included adult out-of-hospital cardiac arrest of presumed cardiac pathogenesis. On October 2012, a treatment protocol using SAED was introduced after years of manual defibrillation. The effect of the SAED implementation on the time to first shock, successful cardioversion, and patient outcomes was assessed using interrupted time series regression adjusting for arrest factors and temporal trend. Of the 14 776 cases, 10 224 (69.2%) and 4552 (30.8%) occurred during the manual and SAED protocols, respectively. Although the proportion of patients shocked within 2 minutes of arrival increased during the SAED protocol for initial shockable rhythms (from 58.9% to 69.2%; P<0.001), there was no difference in unadjusted rate of successful cardioversion after first shock (from 12.3% to 13.8%; P=0.13). After adjustment, the odds of delivering the first shock within 2 minutes of arrival increased under the SAED protocol (adjusted odds ratio [AOR], 1.72; 95% confidence interval [CI], 1.32-2.26; P<0.001). Despite this, the SAED protocol was associated with a reduction in survival to hospital discharge (AOR, 0.71; 95% CI, 0.55-0.92; P=0.009), event survival (AOR, 0.74; 95% CI, 0.62-0.88; P=0.001), and prehospital return of spontaneous circulation (AOR, 0.81; 95% CI, 0.68-0.96; P=0.01) when compared with the manual protocol. There was also no improvement in the rate of successful cardioversion after first shock (AOR, 0.73; 95% CI, 0.51-1.06; P=0.10).

CONCLUSIONS

Although SAED improved the time to first shock, this did not translate into higher rates of successful cardioversion or survival after out-of-hospital cardiac arrest. Advanced life support providers should be trained to use a manual defibrillation protocol.

Effective deployment of public-access automated external defibrillators to improve out-of-hospital cardiac arrest outcomes

Out‐of‐hospital cardiac arrest (OHCA) is a major health concern in Japan and other developed countries with aging populations. Improvements in OHCA outcomes require streamlining the chain of survival. Deployment of public‐access automated external defibrillators (PADs) and defibrillation by bystanders is one strategy that may streamline the chain by reducing the time to defibrillation in individuals with shockable rhythms. Although the effectiveness of PAD programs in increasing survival to discharge has been reported, there have been criticisms and concerns about the small population impact, cost‐effectiveness, and potential negative impact on those with nonshockable rhythms. This article reviews relevant literature regarding the effectiveness and concerns regarding PAD for OHCA.

[Worldwide experience with automated external defibrillators: What have we achieved? What else can we expect?]

INTRODUCTION

In Germany approximately 70,000-100,000 SCD patients die from sudden cardiac death (SCD). SCD is not caused by a single factor but is a multifactorial problem. In 50 % of SCD victims, sudden cardiac death is the first manifestation of heart disease. SCD is caused by ventricular tachyarrhythmias in approximately 90 % of patients, whereas SCD is caused by bradyarrhythmias in 5-10 % of the patients.

METHODS

Risk stratification is not possible in the majority of them prior to the fatal event. Early defibrillation is the method of choice to terminate ventricular fibrillation. Therefore, it is mandatory to install automatic external defibrillators (AED) in places with many people. There is general agreement that early defibrillation with automated external defibrillators (AED) is an effective tool to treat patients with ventricular fibrillation and will improve survival.

CONCLUSION

It seems necessary to teach cardiocompression and AED use, also to children and adolescents. AED therapy "at home" did not improve survival in patients with cardiac arrest and can not be recommended.

Monitoring of in-hospital cardiac arrest events with the focus on Automated External Defibrillators--a retrospective observational study

Background

Patients with cardiac arrest have lower survival rates, when resuscitation performance is low. In In-hospital settings the first responders on scene are usually nursing staff without rhythm analysing skills. In such cases Automated External Defibrillators (AED) might help guiding resuscitation performance. At the Wuerzburg University Hospital (Germany) an AED-program was initiated in 2007.

Aim of the presented study was to monitor the impact of Automated External Defibrillators on the management of in-hospital cardiac arrest events.

Methods

The data acquisition was part of a continuous quality improvement process of the Wuerzburg University Hospital. For analysing the CPR performance, the chest compression rate (CCR), compression depth (CCD), the no flow fraction (NFF), time interval from AED-activation to the first compression (TtC), the time interval from AED-activation to the first shock (TtS) and the post schock pause (TtCS) were determined by AED captured data. A questionnaire was completed by the first responders.

Results

From 2010 to 2012 there were 359 emergency calls. From these 53 were cardiac arrests with an AED-application. Complete data were available in 46 cases. The TtC was 34 (32–52) seconds (median and IQR).The TtS was 30 (28–32) seconds (median and IQR) . The TtCS was 4 (3–6) seconds (median and IQR) . The CCD was 5.5 ± 1 cm while the CCR was 107 ± 11/min. The NFF was calculated as 41 %.

ROSC was achieved in 21 patients (45 %), 8 patients (17 %) died on scene and 17 patients (37 %) were transferred under ongoing CPR to an Intensive Care Unit (ICU).

Conclusion

The TtS and TtC indicate that there is an AED-user dependent time loss. These time intervals can be markedly reduced, when the user is trained to interrupt the AED’s “chain of advices” by placing the electrode-paddles immediately on the patient’s thorax. At this time the AED switches directly to the analysing mode. Intensive training and adaption of the training contents is needed to optimize the handling of the AED in order to maximize its advantages and to minimize its disadvantages.