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

Semiautomated external defibrillators for in-hospital early defibrillation: a comparative study

OBJECTIVES

Semiautomated external defibrillators (AEDs) should be considered as a means to facilitate in-hospital early defibrillation (IHED) in areas where advanced life support rescuers are not readily available. In this study, we aimed to develop a checklist and a measurement protocol to evaluate and compare AEDs by assessing factors that may affect IHED.

METHODS

A clinical and technical comparison of six AEDs was performed. Technical specifications were analyzed, while an emergency team evaluated ergonomics and appropriateness for IHED at Bambino Gesù Children's Hospital. A measurement protocol was implemented, which aimed to assess the ability of defibrillators to recognize shockable and nonshockable rhythms, accuracy of delivered energy, and charging time.

RESULTS

Designs of AEDs differed in several features which influence their appropriateness for IHED. Some units showed poor ergonomics and instructions/feedback for cardiopulmonary resuscitation. Differences between defibrillators in recognizing shockable and nonshockable rhythms emerged for polymorphic ventricular tachycardia waveforms and when the frequency and amplitude of input signals varied. Tests for accuracy revealed poor performances at low and high impedance levels for most AEDs. Notably, differences greater than 20 seconds were found in the time from power-on to "ready for discharge."

CONCLUSIONS

The approach we used to assess AEDs allowed us to evaluate their appropriateness with respect to the organizational context, to measure their parameters, and to compare models. Results showed that ergonomics and/or performances (timing and accuracy) could be improved in each device.

Retention of skills in medical students following minimal theoretical instructions on semi and fully automated external defibrillators

AIM OF THE STUDY

There is consent that the use of automated external defibrillators (AED) by laypersons improves survival rates in case of cardiac arrest, but no evident consensus exists on the content and duration of training for this purpose. Acceptance of the implementation of Public Access Defibrillation programmes will depend on practical and target-oriented training concepts. The aim of this prospective randomised interventional study was to evaluate long-term effects of a specific, minimal training programme on using semiautomatic and fully automatic AEDs in simulated cardiac arrest.

MATERIALS AND METHODS

In a mock cardiac arrest scenario 59 medical students with no specific previous medical education were tested during their first semester at medical school. Students who passed any medical emergency training were excluded. The subjects were evaluated before and after attending specified instructions of 15 min duration and after a period of 6 months. Main end points were time to first shock, electrode-positioning and safety throughout the procedure.

RESULTS

Mean time to first shock without prior instructions was 77.7+/-17.05 s. After instruction there was a significant improvement to 56.5+/-9.5 s (p<or=0.01) and after 6 months this time had only slightly elongated (59.9+/-8.9 s; p<or=0.01). Initially, correct electrode placement was observed in 84.4%. No difference was found immediately and 6 months after instructions (93.2% and 98.3%). All individuals performed safely.

CONCLUSION

First year medical students with minimal instruction are able to use semiautomatic as well as fully automatic AED sufficiently fast and safe without prior training. A significant improvement in time to first shock can be detected up to 6 months after receiving non-specific instructions of 15 min duration.

Training lay-people to use automatic external defibrillators: are all of their needs being met?

AIMS

We explored the experiences of lay people who have been trained to use automatic external defibrillators. The research questions were: (1) How can training courses help prepare people for dealing with real life situations? (2) Who is ultimately responsible for providing critical incident debriefing and how should this be organised? (3) What is the best process for providing feedback to those who have used an AED?

METHODOLOGY

Fifty-three semi-structured, qualitative interviews were conducted, some with those who had been trained and others with trainers. Locations included airports, railway stations, private companies and first responder schemes. Geographically, we covered Nottinghamshire, Lincolnshire, Yorkshire, Staffordshire, Essex and the West Midlands in the UK.

RESULTS

Our analysis of the data indicates that most people believe scenarios based within their place of work were most useful in preparing for 'real life'. Many people had not received critical incident debriefing after using an AED. There were a variety of systems in place to provide support after an incident, many of which were informal.

CONCLUSION

Training scenarios should be conducted outside the classroom. There should be more focus on critical incident debriefing during training and a clear identification of who should provide support after an incident. Other issues which were of interest included: (1) people's views on do not attempt resuscitation (DNAR); (2) perceived boundaries of responsibility when using an AED; (3) when is someone no longer 'qualified' to use an AED?

CPREzy™ improves performance of external chest compressions in simulated cardiac arrest

AIM OF THE STUDY

External chest compression (ECC) is an essential part of cardiopulmonary resuscitation and usually performed without any adjuncts. Although different supportive devices have been developed, none have yet been implemented as a standard procedure to guide rescuers in resuscitation. This study investigates the effects of the CPREzy-pad on ECC performed by first year medical students during simulated cardiac arrest.

MATERIALS AND METHODS

Two hundred and two subjects were randomised and asked to perform 5 min of single-rescuer-CPR. Group 1 (n = 111) was taught classic ECC, followed by ECC with the CPREzy and was tested in ECC with the CPREzy. Group 2 (n = 91) was taught and tested in classic ECC only. One week later each group was divided: Group 1A was tested in ECC with the CPREzy again; Group 1B was tested in classic ECC. Group 2A was taught and tested in ECC with CPREzy; Group 2B was tested in classic ECC again. Primary endpoints were compression rate (90-110/min) and compression depth (40-50mm).

RESULTS

Comparing groups 1 and 2, ECC was significantly superior with CPREzy (correct rate: 93.7% versus 19.8%, p < or = 0.01; depth: 71.2% versus 34.1%, p < or = 0.01). The group tested with CPREzy initially 1 week later (2A; n = 36) improved significantly in correct compression rate (19.8% versus 88.9%, p < or = 0.01) and compression depth (34.1% versus 75.0%, p < or = 0.02). The control-group (2B; n = 55) without CPREzy demonstrated poor performance in both evaluations (correct rate: 19.8% versus 25.5%, depth: 34.1% versus 43.6%).

CONCLUSION

CPREzy as a simple portable and re-usable device is able to improve performance of ECC in simulated cardiac arrest.

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

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

A reference automated external defibrillator provider course for Europe

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CPR in medical schools: learning by teaching BLS to sudden cardiac death survivors--a promising strategy for medical students?

BACKGROUND

Cardiopulmonary resuscitation (CPR) training is gaining more importance for medical students. There were many attempts to improve the basic life support (BLS) skills in medical students, some being rather successful, some less. We developed a new problem based learning curriculum, where students had to teach CPR to cardiac arrest survivors in order to improve the knowledge about life support skills of trainers and trainees.

METHODS

Medical students who enrolled in our curriculum had to pass a 2 semester problem based learning session about the principles of cardiac arrest, CPR, BLS and defibrillation (CPR-D). Then the students taught cardiac arrest survivors who were randomly chosen out of a cardiac arrest database of our emergency department. Both, the student and the Sudden Cardiac Death (SCD) survivor were asked about their skills and knowledge via questionnaires immediately after the course. The questionnaires were then used to evaluate if this new teaching strategy is useful for learning CPR via a problem-based-learning course. The survey was grouped into three categories, namely "Use of AED", "CPR-D" and "Training". In addition, there was space for free answers where the participants could state their opinion in their own words, which provided some useful hints for upcoming programs.

RESULTS

This new learning-by-teaching strategy was highly accepted by all participants, the students and the SCD survivors. Most SCD survivors would use their skills in case one of their relatives goes into cardiac arrest (96%). Furthermore, 86% of the trainees were able to deal with failures and/or disturbances by themselves. On the trainer's side, 96% of the students felt to be well prepared for the course and were considered to be competent by 96% of their trainees.

CONCLUSION

We could prove that learning by teaching CPR is possible and is highly accepted by the students. By offering a compelling appreciation of what CPR can achieve in using survivors from SCD as trainees made them go deeper into the subject of resuscitation, what also might result in a longer lasting benefit than regular lecture courses in CPR.

Minimal instructions improve the performance of laypersons in the use of semiautomatic and automatic external defibrillators

INTRODUCTION

There is evidence that use of automated external defibrillators (AEDs) by laypersons improves rates of survival from cardiac arrest, but there is no consensus on the optimal content and duration of training for this purpose. In this study we examined the use of semiautomatic or automatic AEDs by laypersons who had received no training (intuitive use) and the effects of minimal general theoretical instructions on their performance.

METHODS

In a mock cardiac arrest scenario, 236 first year medical students who had not previously attended any preclinical courses were evaluated in their first study week, before and after receiving prespecified instructions (15 min) once. The primary end-point was the time to first shock for each time point; secondary end-points were correct electrode pad positioning, safety of the procedure and the subjective feelings of the students.

RESULTS

The mean time to shock for both AED types was 81.2 +/- 19.2 s (range 45-178 s). Correct pad placement was observed in 85.6% and adequate safety in 94.1%. The time to shock after instruction decreased significantly to 56.8 +/- 9.9 s (range 35-95 s; P < or = 0.01), with correct electrode placement in 92.8% and adequate safety in 97%. The students were significantly quicker at both evaluations using the semiautomatic device than with the automatic AED (first evaluation: 77.5 +/- 20.5 s versus 85.2 +/- 17 s, P < or = 0.01; second evaluation: 55 +/- 10.3 s versus 59.6 +/- 9.6 s, P < or = 0.01).

CONCLUSION

Untrained laypersons can use semiautomatic and automatic AEDs sufficiently quickly and without instruction. After one use and minimal instructions, improvements in practical performance were significant. All tested laypersons were able to deliver the first shock in under 1 min.

In hospital cardiac arrest: a role for automatic defibrillation

INTRODUCTION

Sudden cardiac death (SCD) survival decreases by 10% for each minute of delay in defibrillation, however, survival rates of 98% can be achieved when defibrillation is accomplished within 30s of collapse. Recently, a fully automated external cardioverter-defibrillator (AECD) was approved by the FDA for in-hospital use. The AECD can be programmed to automatically defibrillate when a life threatening ventricular arrhythmia occurs. The purpose of this study was to assess the potential impact of in-hospital AECDs on the critical time to defibrillation in monitored hospital units.

METHODS

Mock emergency (n = 18) were conducted using simulated ventricular fibrillation in various monitored units. Observers were stationed to record the time staff responded to the arrhythmia, and the time to shock. These times were compared to an AECD protocol that defibrillates automatically in an average of 38.3 s from onset of arrhythmia (n = 18).

RESULTS

Staff versus AECD response time to arrhythmia (s) was 76.3 +/- 113.7 (CI 19.8-132.8) versus 7.6 +/- 0.6 (CI 7.3-7.9). Staff versus AECD time to shock was 169.2 +/- 103.1 (CI 117.9-220.4) versus 38.3 +/- 0.7 (CI 37.9-38.6). P-values are <0.0001 for differences between the groups.

CONCLUSION

The use of AECDs on monitored units would significantly reduce the critical time to defibrillation in patients with SCA. We anticipate this would translate to improved survival rates, and better neurologic outcomes.

Skill acquisition and retention in automated external defibrillator (AED) use and CPR by lay responders: a prospective study

This prospective study evaluated the acquisition and retention of skills in cardio-pulmonary resuscitation (CPR) and the use of the automated external defibrillator (AED) by lay volunteers involved in the Department of Health, England National Defibrillator Programme. One hundred and twelve trainees were tested immediately before and after and initial 4-h class; 76 were similarly reassessed at refresher training 6 months later. A standardised test scenario that required assessment of the casualty, CPR and the use of on AED was evaluated using recording manikin data and video recordings. Before training only 44% of subjects delivered a shock. Afterwards, all did so and the average delay to first shock was reduced by 57 s. All trainees placed the defibrillator electrodes in an "acceptable" position after training, but very few did so in the recommended "ideal" position. After refresher training 80% of subjects used the correct sequence for CPR and shock delivery, yet a third failed to perform adequate safety checks before all shocks. The trainees self-assessed AED competence score was 86 (scale 0-100) after the initial class and their confidence that they would act in a real emergency was rated at a similar level. Initial training improved performance of all CPR skills, although all except compression rate had deteriorated after 6 months. The proportion of subjects able to correctly perform most CPR skill was higher following refresher training that after the initial class. Although this course was judged to be effective in teaching delivery of counter-shocks, the need was identified for more emphasis on positioning of electrodes, pre-shock safety checks, airway opening, ventilation volume, checking for signs of a circulation, hand positioning, and depth and rate of chest compressions.

Public use of automated external defibrillators

BACKGROUND

Automated external defibrillators save lives when they are used by designated personnel in certain public settings. We performed a two-year prospective study at three Chicago airports to assess whether random bystanders witnessing out-of-hospital cardiac arrests would retrieve and successfully use automated external defibrillators.

METHODS

Defibrillators were installed a brisk 60-to-90-second walk apart throughout passenger terminals at O'Hare, Midway, and Meigs Field airports, which together serve more than 100 million passengers per year. The use of defibrillators was promoted by public-service videos in waiting areas, pamphlets, and reports in the media. We assessed the time from notification of the dispatchers to defibrillation, survival rate at 72 hours and at one year among persons with cardiac arrest, their neurologic status, and the characteristics of rescuers.

RESULTS

Over a two-year period, 21 persons had nontraumatic cardiac arrest, 18 of whom had ventricular fibrillation. With two exceptions, defibrillator operators were good Samaritans, acting voluntarily. In the case of four patients with ventricular fibrillation, defibrillators were neither nearby nor used within five minutes, and none of these patients survived. Three others remained in fibrillation and eventually died, despite the rapid use of a defibrillator (within five minutes). Eleven patients with ventricular fibrillation were successfully resuscitated, including eight who regained consciousness before hospital admission. No shock was delivered in four cases of suspected cardiac arrest, and the device correctly indicated that the problem was not due to ventricular fibrillation. The rescuers of 6 of the 11 successfully resuscitated patients had no training or experience in the use of automated defibrillators, although 3 had medical degrees. Ten of the 18 patients with ventricular fibrillation were alive and neurologically intact at one year.

CONCLUSIONS

Automated external defibrillators deployed in readily accessible, well-marked public areas in Chicago airports were used effectively to assist patients with cardiac arrest. In the cases of survivors, most of the users had no duty to act and no prior training in the use of these devices.

Automated external defibrillation as part BLS: implications for education and practice

The latest Adult Basic Life Support (BLS) guidelines support the inclusion of the use of the automated external defibrillator (AED), as part of basic life support (BLS). Emphasis on the provision of early defibrillation as part of BLS acknowledges the importance of this manoeuvre in the successful termination of ventricular fibrillation. The ramifications of such changes for both first responders and organisations implementing the guidelines should not be underestimated. Issues relating to resourcing, content and duration of training and retraining, auditing and evaluation require further exploration. To consider these issues now seems particularly pertinent, given the recent launch of the UK Government's paper on public health, 'Saving Lives-Our Healthier Nation' which seeks to deploy AEDs in busy public places for use by trained members of the lay public. Additionally, defibrillation has been identified as one of the key competencies that all trained nurses and other health care providers should be able to undertake. This paper will consider the background to the current guideline changes, analyse the wider implications of translating the recommendations into practice, and offer possible solutions to address the issues raised. Whilst the analysis is particularly pertinent to the United Kingdom, many of the issues raised have international importance.

Application of a cardiac arrest score in patients with sudden death and ST segment elevation for triage to angiography and intervention

The aim of this study was to test a previously validated, prognostic, cardiac arrest score in patients with ST segment elevation acute myocardial infarction (AMI) who suffered a witnessed cardiac arrest and survived to emergency department admission. A consecutive series constructed retrospectively from a sudden death database (n = 22) of patients with ST segment elevation AMI resuscitated from cardiac arrest underwent angiography and angioplasty of the culprit vessel within 24 hours of presentation. A cardiac arrest score was assigned to each case by explicit criteria present on evaluation. Primary outcomes were survival to hospital discharge and the degree of neurological recovery during the hospitalization. All patients underwent successful coronary angioplasty and 77% received adjunctive intraaortic balloon counterpulsation. The overall rate of survival to discharge was 41%. For cardiac arrest scores of 0, 1, 2, and 3, respectively, the rates of neurologic recovery were 0 (0%) of 4 (95% CI 0-53%), 3 (50%) of 6 (95% CI 15-85%), 2 (67%) of 3 (95% CI 13-98%), and 9 (100%) of 9 (95% CI 72-100%), and the rates of survival to discharge were 0 (0%) of 4, (95% CI 0-53%), 2 (33%) of 6 (95% CI 6-74%), 2 (67%) of 3 (95% CI 13-98%), and 9 (100%) of 9 (95% CI 72-100%), P < 0.01 for both outcomes over ascending scores. These results suggest appropriate patients for primary angioplasty after cardiac arrest are those with ST segment elevation AMI and an emergency department cardiac arrest score of > or = 2, thus predicting a 11 (92%) of 12 (95% CI 65-100%) chance of survival to discharge.

Should ward nurses be using automatic external defibrillators as first responders to improve the outcome from cardiac arrest? A systematic review of the primary research

INTRODUCTION

The outcome from in-hospital cardiac arrest has improved little since the implementation of cardiopulmonary resuscitation 40 years ago. Early defibrillation improves survival following ventricular fibrillation and pulseless ventricular tachycardia. The emergence of automatic external defibrillators and advisory defibrillators has been heralded as the answer to defibrillation delays in-hospital.

AIM

To locate and evaluate the evidence supporting automatic external defibrillator use in-hospital on general wards.

METHOD

A systematic review of indexed and grey literature to identify primary research.

RESULTS

Fifteen in-hospital automatic external defibrillator studies were located, five met the inclusion criteria.

CONCLUSIONS

There is limited primary research evaluating automatic external defibrillators in-hospital. Manual defibrillators remain the most commonly used device for in-hospital defibrillation. Automated external defibrillators offer an alternative to manual defibrillation providing they have a screen and manual override capability, and the technology for pacing is close to hand. For in-hospital automatic external defibrillator programmes to be effective a change in nursing philosophy must occur, and defibrillation must become an expected rather than an extended nursing role.

Performance and error analysis of automated external defibrillator use in the out-of-hospital setting

STUDY OBJECTIVE

We determined whether automated external defibrillators (AEDs) can meet the American Heart Association performance criteria to detect and shock unstable cardiac rhythms (ventricular fibrillation [VF], ventricular tachycardia [VT]) in the setting of an out-of-hospital cardiac arrest.

METHODS

AED performance was reviewed for cardiac arrests occurring between January 1, 1995, and December 31, 1997. After every cardiac arrest, data regarding each rhythm analyzed and subsequent response (shock or no shock) were downloaded from the AED memory module. The study paramedic and study physician independently reviewed each case and interpreted cardiac rhythms from downloaded AED data. The emergency medical services medical director resolved all discrepancies in a blinded manner. All cases of out-of-hospital cardiac arrest in which an AED was turned on and a rhythm analyzed were included. The primary objective was the correct identification and defibrillation of VF or VT. Sensitivity, specificity, and predictive values with 95% confidence intervals (CIs) were calculated. Sources of error in AED rhythm management are also described.

RESULTS

A total of 3,448 AED rhythms were available for interpretation. Sensitivity and specificity for appropriate AED management of a shockable (VF or VT) rhythm were 81.0% (95% CI 77.9% to 83.8%) and 99.9% (95% CI 99.7% to 100%), respectively. Positive and negative predictive values were 99.6% (95% CI 98.7% to 99.9%) and 95.5% (95% CI 94.7% to 96.2%), respectively. There were 132 errors associated with AED management. Two errors resulted in delivery of an inappropriate shock. In the remaining 130 errors, a shockable rhythm was not shocked. Fifty-five (42.3%) errors were AED dependent, 70 (53.9%) were operator dependent, and 5 (3.9%) were unclassified.

CONCLUSION

The AED had high specificity and moderately high sensitivity in detecting and shocking unstable cardiac rhythms in the out-of-hospital setting. Few cardiac rhythms were mismanaged by the AED. Elimination of operator-dependent errors could increase AED sensitivity.