Ana Vigário, Daniela Rodrigues, Diana Marques, Fátima Marisa Queirós, Inês Garrido, Leonor Matos, Liliana Tavares

Introduction to MedicineMay 2nd, 2007

Porto University Medical School

The efficacy of automated external defibrillators programs in

the community

Systematic review

• Introduction: • Automated external defibrillator (AED) definition

• How does an AED work

• AED programs

• Sudden cardiac death (SCD) definition

• Epidemiology of SCD

• Prevention of SCD

• SCD in the community

• Objective of the study

• Material and Methods• Query used in the systematic review

• Exclusion and Inclusion criteria

• Results

• Conclusions/Discussion

• Gantt Map of the group work

Contents

Small computerized device that delivers shock to victims of

ventricular fibrillation (VF) cardiac arrest. (1)

Introduction

Automated external defibrillator (AED)

The device is attached to the victim by adhesive pads or electrodes. It records and analyzes the victims’ electrocardiogram rhythm,

informs the rescuer if a shock is needed and provides voice and audio prompts to guide the rescuer through all steps of AED use. (1)

Automated external defibrillator

How does it work?

Over the past two decades:

AED have been developed and improved (2)

The use of AED’s was expanded:- to first-responders (police officers, firefighters, security

guards, flight attendants).- to laypeople who witness an arrest. (3)

The AED’s are placed in public areas such as: airports, sporting areas, casinos, shopping malls, etc. (4)

An organized and practiced response requires rescuers trained and equipped to:

- recognize emergencies, activate emergency medical services, provide CPR and provide defibrillation in situations where quickness is determinant. (5)

Automated external defibrillator programs

Natural cause of death with sudden lost of conscience until 1 hour after the onset of the acute symptoms. (6)

Sudden cardiac death can be the presenting feature of coronary disease.

Key points in the definition of sudden death: non traumatic event unexpected and instant event

Sudden Cardiac Death (SCD)

Definition:

Before a cardiac arrest event, victims present:

• Pulseless ventricular tachycardia (VT)or

• Ventricular fibrillation (VF)

The incidence of out-of-hospital SCD varies with age, gender and the presence of cardiovascular disease. (7)

Sudden Cardiac Death (SCD)

Epidemiology of SCD (I)

• In the United States, SCD affects more than 350 000 people each year.(8)

• Although recent studies show an increased of SCD in the African–American community, it is more prevalent in Caucasians. (8)

• In Europe it affects about 200 000 individuals a year. (9)

• Ventricular fibrillation (VF) is the most common initial rhythm, however, when time elapses VF will gradually deteriorate into asystole, decreasing the chance of survival. (10)

The early defibrillation has demonstrated to be critical in the survival improvement of SCD. (12)

SCA that occurs in apparent healthy individuals cannot be prevented. (13)

Many victims of SCA can survive if bystanders act immediately while VF is still present. (14)

Prevention of SCD in the community

Prevention of SCD in the community

The individual survival is dependent on the defibrillator availability in 4-5 minutes after onset of the event. (15)

Cardiopulmonary resuscitation (CPR) plus defibrillation within 3-5 minutes of collapse can produce high survival rates. (16)

The recent technical improvements in the Automated External Defibrillators (AED) made possible it’s use by lay people. (17)

Provide an early recognition and correction of these dysrhythmias by lay rescuers; (18)

Increase the number of people who receive bystander cardiopulmonary resuscitation (CPR); (18)

Reduce time to defibrillation. (18)

Lay rescuer AED programsLay rescuer AED programs may:

The efficacy is not overall The efficacy is not overall stablished....stablished....

Will AED´s improve Will AED´s improve outcome from sudden outcome from sudden

death?death?

The purpose of our systematic study is to

evaluate whether the implementation of AED

programs in the community reduces overall

mortality from SCD and mantains the initial

quality of life of the survivors.

Objective

Methods

Systematic review of published articles

Bibliographic research on PubMed’s (a medical database) using a previously defined query.

Searching criteria:

from the earliest achievable date until March 2007. Terms used: automated external defibrillator, public

access defibrillation, sudden cardiac arrest, out-of-hospital cardiac arrest, ventricular fibrillation or tachycardia

Selection of the articles based on inclusion and exclusion criteria

Query used to search PubMed:

("automated external defibrillator" OR "automate external defibrillator programs" OR "public access defibrillation" OR "out-of-hospital defibrillation" )

AND

("Death, Sudden, Cardiac"[MeSH] OR "sudden cardiac arrest" OR "sudden cardiac death" OR "out-of-hospital cardiac arrest" OR "Ventricular Fibrillation"[MeSH] OR "ventricular fibrillation" OR "Tachycardia, Ventricular"[MeSH]OR "ventricular tachycardia" OR " emergency life support" OR " cardiopulmunary resuscitation" OR " cardiac arrest" OR " basic life support")

Methods

Total articles found: 225 articles

Inclusion criteria:

Initial tracing (inclusion): performed by three groups, composed of two reviewers, according to the inclusion criteria mentioned below:

1. Articles presented in English, French, Portuguese or Spanish;

2. Articles published in the last 20 years;

3. Aplicated to humans.

4. Studies about AED community programs with lay people, fire-fighters, police officers and paramedic involvement.

5. Articles that have information about quality of life of the survivors after implementation of AED programs or data that made possible it’s calculation

Methods

Exclusion criteria:

• Performed by three groups, composed of two reviewers.

• Selection was made by consense of two reviewers of each group.

• Exclusion criteria: • Not being based on the systematic review’s theme –

concerning studies published about AED programs in the

community.

1. Articles that do not have detailed information about survival

rates at hospital discharge after implementation of AED

programs or data that made possible it’s calculation.

2. Studies with a minimal number of 50 patients included and

programs with a duration of less than 6 months

Methods

Methods

Methods of data extraction:

The articles were carefuly read and the data was extracted by three groups of two reviewers.

The data extraction was done considering the criteria bellow:

•Article (Type of study, duration of the study, number of participants, number of patients who survived, number of witnessed cardiac arrests, etc.)

The data extracted was then treated in an SPSS 14.0 database.

Significance level: <0,05

Methods225 articles obtained from Pubmed´s query

169 articles followed the inclusion criteria

56 articles excluded: did not follow inclusion

criteria

18 articles included: did not follow the exclusion criteria

151 articles were excluded: followed

the exclusion criteria

Re-read the 16 articles selected, extract, and analyze relevant data

2 articles excluded: missing

data

Characteristics of the population of the study:

• Total number of participants: 17268

• Mean of age: 63 years old (Std Deviation = 9.6)

• Mean duration of the studies was 54 months (min: 5, max: 123 months)

• 1679 female participants

• 5271 male participants

Results

ResultsResults

• The rate of survival of approximately for patients whom had VF/VT and the AED was used (n=7 studies) was 33%.

• From the initial 1026 participants, 690 of them had shockable rhythms (VF/VT) (67%).

Total of SCA 1026Total of VF/VT 690Total of survivors who were treated with AED and presented VF/VT 292Total of survivors treated with AED who had VF/VT without neurological damages 223Number of articles 5

Table 4. Evaluation of the total number of survivors who had VF/VT in the beginning.

• In 690 participants who had shockable rhythms (VF/VT) (n=5 studies) 292 of them survived (42%). In these 292 survivors 223, of them survived without neurological damages (76%)

Results

• In 690 participants who had shockable rhythms (VF/VT) (n=5 studies) 292

of them survived (42%). In these 292 survivors 223, of them survived without

neurological damages (76%)

• The number of participants who had a witnessed SCA was 5512 (8 studies),

1474 of those survived (27%), while the number of participants who had a

non-witnessed SCA was 441 (3 studies), 15 of those survived (3%).

• The survival rate of patients assisted by lay persons trained in AED's

management is similar in comparising with paramedics (Mean of lay persons =

38%; Mean of paramedics=36%, Mann-Whitney test for independent samples,

p>0.05).

Total of participants 8410Total of survivors 1605Total of survivors without neurological damages 620Number of studies 9

Results

• Using the data presented in table 5 we calculated the rate of survivors who

after discharge did not present neurological damages. The total number of

survivors after hospital discharge was 1605 (n= 9 studies), 620 of them

without neurological damages (40%).

Table 5. Information regarding quality of life of the participants according to their neurological status.

Results

• Using a parametric test for independent samples it was obtained a significative difference between the rate mortality rate with or without AED (p = 0.04).

• The same method was used with the mortality rate in people with VF/VF with AED and without AED. In fact there is a significative differente between this two rates (p = 0.01).

Results

Graphic 1-This graphic indicates that the majority of deaths occurs in the local where the cardiac arrest took place followed by in-

hospital and after discharge deaths.

Determination of the mortality rate on the different sets

Mortality on the different sets

0

50

100

150

200

1 2 3 4 5 6 7 8 9

Different sets

Nu

mb

er

of

pa

tie

nts

Local In-hospital After discharge

• The rate of survival with the use of AED (33%) clearly indicates the efficacy of its implementation in the community.

• Patients who initially presented with VF/VT have a better chance to survive comparising to those who have non-shockable rhythms

• Witnessed cardiac arrests have a great advantage in terms of the percentage of the survival which largely increases in comparison to non-witnessed cardiac arrests.

• It was verificated that there is no difference in the use of AED by paramedics or laypeople previously trained;as long as there exists previous instruction the efficacy of AED is not related with its users.

Conclusion

• Concerning the use of AED in different places (public places and specific places like casinos or malls), the rate of survival is dependent of the place where the AED is applied.

• In most of the times death occurs immeadiately "at the local", followed by "in hospital" and " after discharge".

• The use of AED also matains the quality of life of the survivors after discharge. The number of participants who were treated with AED and did not have neurological damages was significantly superior to those who had neurological damages.

• The frequency of VF in cardiac arrests is high (67%) which reforces the relevancy of the implementation of AED's programs in community.

Conclusion

• We concluded that the use of the AED programs in the community is effective; however, this can be properly applied to the USA because most of the studies referring this issue were made there.

• The implementation of AED programs is a sustainable and culturally acceptable measure , bringing an undeniable benefit to society and public health.

Conclusion

• Projecto1 gantt.mpp

• SPSS table

• Methods Flowchart

• Participants Flowchart

Annexes

1. A.W. Diack, W.S. Wellborn, R.G. Rullman et al., An automatic cardiac resuscitator for emergency treatment of cardiac arrest. Med Instrum 13 (1979), pp. 78–81. Abstract-EMBASE | Abstract-INSPEC | Order Document | Abstract + References in Scopus | Cited By in Scopus

2. Becker S et al. Minimal instructions improve the performance of layperson in the use of semiautomatic and automatic external defibrillators. Critical Care 2005; 9: 110-16

3. Davies C et al. A national program for on-site defibrillation by lay peolple is selected high risk areas: inicial results. Heart 2005; 91: 1299-302

4. Zipes DP, Wellens HJ. Sudden cardiac death. Circulation. 1998;98:2334-2351

5. Lim S et al. Results of the first five years of the prehospital automatic external defibrillation project in Singapore in the “Utstein style”. Resuscitation, 2005; 64: 49-57

6. Priori S, et all. Task Force on sudden cardiac death. Europace; 2002, 4: 3-18

7. DeVreede-Swagemakers et al. Out-of-hospital cardiac arrest in the 1990’: a population based study in the Maastricht area on incedence, characteristics and survival. JACC 1997; 30: 1500-5

8. Sans S et all. The burden of cardiovascular diseases mortality in Europe. Task force of ESC on cardiocascular mortality and morbidity statistics in Europe. Eur Heart J 1997; 18: 1231-48

References

References9. Ali Hamaad, Angie Ghattas, Fatima Hirani, Gregory Y.H. Lip and Robert J. MacFadyen , University

Department of Medicine, Sandwell and West Birmingham NHS Trust City Hospital, Dudley Road, Birmingham B18 7QH, United Kingdom

10. Waalewijn RA et all. Prevention of deterioration of ventricular fibrillation by basic life support during out-of-hospital cardiac arrest. Resuscitation 2002; 4: 31-6

11. Marenco J et al. Improving survival from sudden cardiac arrest: the role of the automated external defibrillator. JAMA 2001; 285: 1193-200

12. Reinier A. Waalewijn Marië A. Nijpels, Jan G. Tijssen and Rudolph W. Koster Academic Medical Center, Department of Cardiology, University of Amsterdam

13. Larsen MP et al. Predicting survival from out-of-hospital cardiac arrest: a graphic model. Ann Eerg Med 1993; 22:1652-8

14. European Ressucitation Council. Part 2: Adult basic life support and use of automated external defibrillators. Resuscitation 2005; 67: s7-23

15. White R et al. Evolution of a community-wide defibrillation programme experience over 13 years using police/fire personnel and paramedics as responders. Resuscitation, 2005; 65(3): 279-83.

16. The public access defibrillation trial investigators. Public-access defibrillation and survival after out-of-hospital cardiac arrest. NEJM 2004; 351: 637-46

17. Joseph V. Automatic external defibrillators: lessons from the past, present and future . Resuscitation 1999; 41: 219