DOI: 10.12809/hkmj176810
© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
MEDICAL PRACTICE
Public access defibrillation in Hong Kong in 2017
KL Fan, FHKAM (Emergency Medicine)1;
CT Lui, FHKAM (Emergency Medicine)2;
LP Leung, FRCSEd, FHKAM (Emergency Medicine)3
1 Accident and Emergency Department, The University of Hong Kong–Shenzhen Hospital, Shenzhen, China
2 Accident and Emergency Department, Tuen Mun Hospital, Tuen Mun, Hong Kong
3 Emergency Medicine Unit, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
Corresponding author: Dr LP Leung (leunglp@hku.hk)
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Abstract
The concept of public access defibrillation was
proposed more than 20 years ago. Since then, various
programmes have been implemented in many major
cities although not all have been successful. Fourteen
years ago, the question of whether Hong Kong
needed public access defibrillation was raised. This
article aimed to answer this question based on the
best available evidence. Over the years, the clinical
effectiveness of public access defibrillation in out-of-hospital
cardiac arrest has been proven. Nonetheless
various studies have indicated that among others,
cost-effectiveness, knowledge and attitudes of the
public, and incidence of ventricular fibrillation are
important factors that will affect the likelihood of
success of such programmes. In Hong Kong, because
of the long interval between recognition of arrest
and first defibrillation, public access defibrillation
is probably needed. To ensure the success of such
a programme, careful planning in addition to the
installation of more automated external defibrillators
are essential.
Introduction
The prognosis of out-of-hospital cardiac arrest
(OHCA) in Hong Kong is poor. Fewer than one in 44
persons with OHCA survive to hospital discharge.
The number of survivors with good neurological
outcome is even smaller (one in 67 persons with
OHCA).1 Public access defibrillation (PAD) has
been proposed as a strategy to improve survival.
The concept was first put forward by the American
Heart Association Task Force on Automatic External
Defibrillation in 1995.2 There is no strict definition of
PAD but it is considered to include defibrillation by
persons not medically trained. There were initially
four levels of responders, ie persons performing the
defibrillation before the arrival of the emergency
medical services (EMS). Level 1 referred to the
traditional first responders, eg police and firefighters.
Level 2 were persons who had a duty of care, eg life
guards and security personnel. Laypersons who
had been trained in cardiopulmonary resuscitation
(CPR) or use of an automated external defibrillator
(AED) constituted the third level. Level 4 referred to
minimally trained or untrained laypersons who may
respond to an emergency.
Advances in technology have ensured the
current AED is compact in size and easy to operate.
Visual and auditory instructions allow a person
without prior training to perform defibrillation.3
Fourteen years ago, a group of emergency physicians
questioned whether PAD was needed in Hong Kong.4
In response to the culminating scientific evidence to
support the use of PAD in OHCA, and the change
in the environment and population demographics of
Hong Kong over the past 14 years, this paper aimed
to answer the same question again. A literature
search was conducted using the electronic database
of MEDLINE, Embase, and Scopus for primary
clinical studies, as well as Cochrane Reviews and
Health Technology Assessment and Database
for secondary reviews, published from 1995 to
the present. Keywords of cardiac arrest, survival,
defibrillator, defibrillation, effectiveness, and AED
were used singly or in combination. Additionally
a manual search was performed of bibliographies
listed in articles used for review. An article was
included for review if all investigators agreed that it
could provide data to answer the research question.
It is hoped that the findings of this review will inform
the health authorities and the government about
community-based PAD programmes.
Clinical effectiveness of automated external defibrillator
Ventricular fibrillation (VF) is one of the causes of
sudden OHCA. Defibrillation is the most effective
treatment for patients with VF. The probability
of successful defibrillation is time-dependent,
dropping by 7% to 10% with each passing minute.5
Defibrillation by a bystander with an AED prior to
the arrival of EMS may shorten the time between
arrest and defibrillation and thus increase the chance
of survival. Early studies that compared CPR versus
CPR plus AED by level 1 responders, ie police and
firefighters, did not reveal any survival advantage of
using an AED.6 7 In 2004, the PAD trial investigators
published their report on PAD and survival after
OHCA and presented the most convincing evidence
of the clinical effectiveness of an AED.8 They
randomised over 19 000 volunteer responders from
nearly 1000 communities in North America to an
intervention group that used CPR and AED or a
control group that used CPR alone. The intervention
resulted in a 2-fold increase in the chance of survival
to hospital discharge.8 The failure to demonstrate any
benefits of AED in the early studies may be related to
the exclusion of the lay public in using AED. A meta-analysis
that studied nearly 1600 cases of OHCA also
demonstrated an increased probability of survival to
hospital discharge if an AED was used for OHCA
before EMS arrival (relative risk of 1.39 of surviving
to hospital discharge for people treated with CPR
+ AED compared with CPR-only).9 In conclusion,
there is concrete evidence that AED is clinically
effective in OHCA.
Cost-effectiveness of automated external defibrillator
Before a PAD programme is implemented,
policymakers need to consider many factors.
Clinical effectiveness alone is not sufficient to justify
the implementation of a PAD programme when
there are competing demands for resources. An
important question is how cost-effective of an AED
is. Clinical effectiveness cannot be directly translated
into cost-effectiveness. In fact, opinions about the
cost-effectiveness of public placement of AEDs are
divided.10 11
Factors that affect cost-effectiveness
In general, important factors that affect the cost-effectiveness
of public placement of AEDs include
the incidence of OHCA at the placement site, the
existing survival rate of OHCA in the community,
and the number of AEDs required to provide
adequate coverage. Different recommendations exist
regarding the incidence of OHCA. The American
Heart Association (AHA) recommends an AED be
placed in sites where an OHCA can be expected
every 5 years while the European Resuscitation
Council recommends placing an AED in sites where
an OHCA is expected every 2 years.12 13 If cardiac
arrest at the placement site is rare, the AED is
unlikely to be cost-effective. The survival to hospital
discharge rate of OHCA in most regions is lower
than 10%.14 The higher the survival rate, the lower
the incremental benefit of adding an AED. It should
also be noted that the survival rate is influenced by
multiple factors and is not easily modifiable. A way to
evaluate adequacy of coverage by an AED is to check
whether a layperson can get an AED to the patient
in 1 to 1.5 minutes.15 Based on the average speed of
brisk walking, this can be translated into an AED
being placed within 100 metres of a cardiac arrest.
Nonetheless it is difficult to estimate the number of
AEDs required even with perfect matching with the
sites of possible arrest. This is because historical data
used for matching cannot predict the future risk of
an arrest at the same site. Therefore, the incidence
of cardiac arrest at the placement site is probably a
more significant factor to consider when the cost-effectiveness
of an AED is analysed. A number of
studies have been conducted in the last decade on the
cost-effectiveness of AED in public sites in terms of
cost per quality-adjusted life year (QALY). Depending
on the analytic model, maintenance and system
support cost and the chance that the AED was used,
in turn related to the incidence of cardiac arrests,
the QALY ranged from US$31 000 to $198 000.16 17 18
Overall these studies concluded that sites where the
incidence of cardiac arrests is more than once every 5
to 7 years will assume a more sustainable cost-benefit
for AED placement. Examples include casinos,
airports, and fitness centres.19
It is more than clinical effectiveness and cost-effectiveness
Presence of an AED does not mean that it will or
can be used. The modern AED is easy to operate and
skill retention by a lay rescuer is good. Data from the
PAD trial indicate that it took 7 minutes only for re-training
in AED operation more than a year after the
initial training.20 Nonetheless completion of AED
training does not guarantee that lay responders will
use it when it is needed. In a Finnish study, the AED
was available but not used in 65% of OHCAs.21 A
similar figure was found in the PAD trial.8 There are
likely multiple reasons for this high underutilisation
rate. It may be that the responder is simply unaware
of the presence of an AED or does not know its
location. In addition, the public’s willingness to
use the AED may play a part. Fear of legal liability
because a lack of Good Samaritan legislation is
sometimes quoted as a reason for not providing help
to the needy.22 Factors related to the AED itself may
also be a concern. A survey on the functional status
of public AEDs by Haskell et al23 identified problems
such as battery expiry, inaccessibility, and invisibility
of the AED. In other words, mere installation of
AEDs is not enough to ensure success in a PAD
programme. Proper organisation and maintenance
of the AEDs must accompany any PAD programme.
Another important factor is the characteristics
of the population at risk, eg age of patients with
sudden cardiac death. The incidence of VF is lower
in those older than 70 years than those below.24
The overall incidence of VF in OHCA has also
fallen over the last two decades.25 This is believed
to be a result of improved primary and secondary
prevention of coronary heart disease as evidenced by
the drop in the associated mortality in many parts
of the world.26 Since defibrillation is only effective
for OHCA with an initial rhythm of VF or pulseless
ventricular tachycardia (VT), the need to implement
PAD in regions, where the risk of VF is low, is less
compelling.
Whether public access defibrillation is needed in Hong Kong
On the basis of the previous discussion, this question
is to be addressed from two perspectives: the
likelihood of PAD to improve survival of OHCA in
Hong Kong, and factors that will affect the likelihood
of successful implementation of a PAD programme.
Likelihood of public access defibrillation to improve survival of out-of-hospital
cardiac arrest
The chain of survival is a widely accepted framework
to improve OHCA survival. The chain is composed
of early recognition with a call for EMS, early CPR,
early defibrillation, effective advanced life support,
and integrated post-arrest care. Almost all early local
studies of OHCA highlighted the need to strengthen
particularly the first three links in the chain.27 28 29 30 Of
note, OHCA patients with VF in Hong Kong have
a better prognosis than those with a non-shockable
rhythm.31 32 33 The rate of survival to hospital discharge
of patients with VF initially is 6 times that of
patients with a non-VF rhythm.33 It is therefore not
surprising to find that the time to first defibrillation
is an independent predictor of OHCA survival in
Hong Kong.1
Over the past 20 years, there has been a
remarkable improvement in the time from arrest
recognition to first defibrillation. The time interval
was shortened by nearly 11 minutes from 23 minutes
to 12 minutes.1 34 A possible important contribution to this improvement is the reduced recognition-to-activation interval from over 7 minutes to almost instantly. The reason for this reduction is
unknown although wider use of mobile phones is
a possibility. Whatever the reason, a time gap of at
least 12 minutes between collapse and defibrillation
is still far from desirable. The chance of successful
defibrillation remains low. It is vital that means to
reduce this time gap be found in order to increase
the chance of successful defibrillation. Fourteen
years ago, public education about OHCA, graded
dispatch by ambulances, and a first responder (AED)
programme by police or firefighters were discussed.4
No local studies have specifically addressed the
issue of public education. On the contrary, there
is evidence that the percentage of the public who
have received CPR training has increased over the
last 10 years.35 36 Whether this increase in number
of CPR-trained citizens can be translated to an
increase in OHCA awareness is questionable. This
is because even in the survey published in 2014, only
21% of the 1013 respondents had been trained; and
overall, their CPR knowledge was poor.35 A graded
dispatch system refers to one that prioritising the
EMS response time is based on the urgency of calls.
Similar to 14 years ago, there remains concern about
affecting the overall service commitment by the Fire
Services Department. It is unlikely that this practice
will be adopted in the foreseeable future. With regard
to the last suggestion to recruit police or firefighters
as first responders, overseas experience has already
shown that it is unlikely to improve OHCA survival.6 7
Based on the calculation of the investigators 14 years
ago, employing this means could reduce the collapse
to defibrillation interval by 4 minutes. Even with
this optimistic assumption, the interval of 8 minutes
remains long when applying the latest data. As a
result, PAD by level 2 to 4 responders is probably
needed to shorten the time to first defibrillation
to 5 minutes or shorter, and hopefully improve the
probability of OHCA survival.
Factors affecting the likelihood of success of
a public access defibrillation programme
Public access defibrillation primarily involves public
placement of AEDs to be used by non–medically
trained members of the public in OHCA patients
who present with a shockable rhythm. Factors
that may affect the success of a PAD programme
are multiple and those specific to Hong Kong are
discussed below.
Public placement of AEDs has to be pre-planned.
Evidence suggests that unguided AED
placement is not effective in improving survival
in OHCA.37 In general, appropriate sites include
locations where one can expect an OHCA every 5
years (AHA recommendation), EMS response time
beyond 5 minutes, or facilities serving high-risk
people.38 How the sites of AED placement are related
to the cost-effectiveness of a PAD programme has
also been discussed. In Hong Kong, because there
is no compulsory AED registry, the location of all
AEDs is unknown to the public. To make the best
use of these AEDs, first of all, their location should
be known by the public. The Government is in the
best position to lead the development of an AED
registry. Efforts to facilitate public knowledge of AED
locations are also underway. For instance, a mobile
phone application with an AED locating function
is now available.39 Besides, the AED should be
accessible by the public. A study of the accessibility
and availability of 207 AEDs in 670 facilities in New
Territories (NT) West published in 2014 provided
some insight into this issue.40 The investigators
found that many of the AEDs (37.7%) were placed in
schools in NT West. Whether these AEDs were truly
accessible by the public was questionable as schools
have limited opening hours. Nonetheless in Hong
Kong, most OHCAs occur with the patient at home.
Only 13.5% of cases occurred in public places or
streets.1 Detailed planning of AED placement is thus
essential to ensure that they are accessible and can
be used by the public in an emergency. Regarding
accessibility, Hong Kong may take reference from
Japan and Singapore. In Japan, AEDs can be found in
many vending machines on the streets and internet-based
maps for AED location have been created in
several cities.41 In 2015, Singapore launched a pilot
programme that installed an AED in taxis with taxi
drivers trained to use it.42
Since it is expected that an AED will be used
by a layperson, public knowledge of and attitude to
AED will influence the success of a PAD programme.
According to a recently published survey, only 18%
of respondents would use an AED in an OHCA
and approximately 77% had no knowledge of the
location of an AED near their home or workplace.22
These findings probably explain the very low rate of
bystander defibrillation (1.4%) in OHCA in Hong
Kong.1 Simply increasing the number of AEDs
installed without more extensive engagement of
the public is bound to fail. Education, including
recurrent training in AED use, by government or
non-governmental organisations is indispensable in
this aspect.
As defibrillation is only indicated for VF or
pulseless VT, the incidence of these shockable
rhythms in OHCA is an important consideration
in a PAD programme. In Hong Kong, a fall in the
incidence of VF in OHCA has been observed
alongside a similar downward trend elsewhere.1 28
The latest study revealed an incidence rate of 8.7%.1
Whether the advanced age of the local OHCA
patients is a contributing factor is unknown. It
seems reasonable to postulate that like elsewhere,
improved medical care of patients with coronary
artery disease may be contributory. Nonetheless
caution is needed in interpreting this incidence
rate when PAD is considered. It is well known that
patients with VF will soon become asystolic in the
absence of any intervention. With a call to patient’s
side with an interval of 9 minutes by the EMS, it
is possible that a proportion of VF cases will have
already degenerated into asystole when the EMS
connect them to the cardiac monitor. It has been
estimated that about 53% of patients may be in VT
or VF within 4 minutes of collapse from OHCA.43
If an effective PAD programme is in place, more VF
cases will be identified by the AED machine.
Conclusion
Automated external defibrillator is clinically effective
in improving the survival outcome of OHCA. Cost-effectiveness
is nonetheless dependent on multiple
factors. In Hong Kong, there is a need to implement
a PAD programme in order to shorten the time to
first defibrillation, with itself being a predictor of
survival. Based on the best available evidence for
Hong Kong, strategic planning, eg matching the
incidence of OHCA with AED placement, ensuring
accessibility, and establishing an AED registry
with an infrastructure of AED maintenance are
recommended. Unguided placement of AEDs is
discouraged because it is likely a waste of resources.
In parallel, public engagement is essential. Both
knowledge and attitude should be enhanced through
education. Early defibrillation is just one of the
links in the chain of survival. From the community
perspective, basic life support by a bystander, eg
CPR, deserves continued encouragement despite the
increased bystander CPR rate to nearly 30% over the
past 14 years. This is because high-quality bystander
CPR may help prevent degeneration to asystole.
Declaration
All authors have disclosed no conflicts of
interest.
References
1. Fan KL, Leung LP, Siu YC. Out-of-hospital cardiac arrest
in Hong Kong: a territory-wide study. Hong Kong Med J
2017;23:48-53.
2. Weisfeldt ML, Kerber RE, McGoldrick RP, et al.
Public access defibrillation. A statement for healthcare
professionals from the American Heart Association Task
Force on Automatic External Defibrillation. Circulation
1995;92:2763. Crossref
3. Eames P, Larsen PD, Galletly DC. Comparison of ease of
use of three automated external defibrillators by untrained
lay people. Resuscitation 2003;58:25-30. Crossref
4. Lo CB, Wong TW, Lai KK. Is public access defibrillation
needed in Hong Kong? Hong Kong Med J 2003;9:113-8.
5. Valenzuela TD, Roe DJ, Cretin S, Spaite DW, Larsen MP.
Estimating effectiveness of cardiac arrest interventions:
a logistic regression survival model. Circulation
1997;96:3308-13. Crossref
6. van Alem AP, Vrenken RH, de Vos R, Tijssen JG, Koster
RW. Use of automated external defibrillator by first
responders in out of hospital cardiac arrest: prospective
controlled trial. BMJ 2003;327:1312. Crossref
7. Sayre MR, Evans J, White LJ, Brennan TD. Providing
automated external defibrillators to urban police officers in
addition to a fire department rapid defibrillation program
is not effective. Resuscitation 2005;66:189-96. Crossref
8. Hallstrom AP, Ornato JP, Weisfeldt M, et al. Public-access
defibrillation and survival after out-of-hospital cardiac
arrest. N Engl J Med 2004;351:637-46. Crossref
9. Sanna T, La Torre G, de Waure C, et al. Cardiopulmonary
resuscitation alone vs. cardiopulmonary resuscitation plus
automated external defibrillator use by nonhealthcare
professionals: a meta-analysis on 1583 cases of out-of-hospital
cardiac arrest. Resuscitation 2008;76:226-32. Crossref
10. Gold LS, Eisenberg M. Cost-effectiveness of automated
external defibrillators in public places: pro. Curr Opin
Cardiol 2007;22:1-4. Crossref
11. Pell J, Walker A, Cobbe SM. Cost-effectiveness of
automated external defibrillators in public places: con.
Curr Opin Cardiol 2007;22:5-10. Crossref
12. Hazinski MF, Idris AH, Kerber RE, et al. Lay rescuer
automated external defibrillator (“public access
defibrillation”) programs: lessons learned from an
international multicenter trial: advisory statement from the
American Heart Association Emergency Cardiovascular
Committee; the Council on Cardiopulmonary,
Perioperative, and Critical Care; and the Council on
Clinical Cardiology. Circulation 2005;111:3336-40. Crossref
13. Handley AJ, Koster R, Monsieurs K, et al. European
Resuscitation Council guidelines for resuscitation 2005.
Section 2. Adult basic life support and use of automated
external defibrillators. Resuscitation 2005;67 Suppl 1:S7-23. Crossref
14. Berdowski J, Berg RA, Tijssen JG, Koster RW. Global
incidences of out-of-hospital cardiac arrest and survival
rates: Systematic review of 67 prospective studies.
Resuscitation 2010;81:1479-87. Crossref
15. Aufderheide T, Hazinski MF, Nichol G, et al. Community
lay rescuer automated external defibrillation programs:
key state legislative components and implementation
strategies: a summary of a decade of experience for
healthcare providers, policymakers, legislators, employers,
and community leaders from the American Heart
Association Emergency Cardiovascular Care Committee,
Council on Clinical Cardiology, and Office of State
Advocacy. Circulation 2006;113:1260-70. Crossref
16. Cram P, Vijan S, Fendrick AM. Cost-effectiveness of
automated external defibrillator deployment in selected
public locations. J Gen Intern Med 2003;18:745-54. Crossref
17. Nichol G, Huszti E, Birnbaum A, et al. Cost-effectiveness
of lay responder defibrillation for out-of-hospital cardiac
arrest. Ann Emerg Med 2009;54:226-35.e1-2.
18. Groeneveld PW, Owens DK. Cost-effectiveness of training
unselected laypersons in cardiopulmonary resuscitation
and defibrillation. Am J Med 2005;118:58-67. Crossref
19. Reed DB, Birnbaum A, Brown LH, et al. Location of cardiac
arrests in the public access defibrillation trial. Prehosp
Emerg Care 2006;10:61-76. Crossref
20. Riegel B, Birnbaum A, Aufderheide TP, et al. Predictors
of cardiopulmonary resuscitation and automated external
defibrillator skill retention. Am Heart J 2005;150:927-32. Crossref
21. Kuisma M, Castren M, Nurminen K. Public access
defibrillation in Helsinki—costs and potential benefits from
a community-based pilot study. Resuscitation 2003;56:149-52. Crossref
22. Fan KL, Leung LP, Poon HT, Chiu HY, Liu HL, Tang WY.
Public knowledge of how to use an automatic external
defibrillator in out-of-hospital cardiac arrest in Hong
Kong. Hong Kong Med J 2016;22:582-8.
23. Haskell SE, Post M, Cram P, Atkins DL. Community public
access sites: compliance with American Heart Association
recommendations. Resuscitation 2009;80:854-8. Crossref
24. Tresch DD, Thakur R, Hoffmann RG, Brooks HL.
Comparison of outcome of resuscitation of out-of-hospital
cardiac arrest in persons younger and older than 70 years
of age. Am J Cardiol 1988;61:1120-2. Crossref
25. Bunch TJ, White RD. Trends in treated ventricular
fibrillation in out-of-hospital cardiac arrest: ischemic
compared to non-ischemic heart disease. Resuscitation
2005;67:51-4. CrossRef
26. World Health Organization (WHO). Health for all
database. Available from: http://www.euro.who.int/en/data-and-evidence/databases. Accessed 1 Mar 2017.
27. Wong TW, Yeung KC. Out-of-hospital cardiac arrest: two
and a half years experience of an accident and emergency
department in Hong Kong. J Accid Emerg Med 1995;12:34-9. Crossref
28. Leung LP, Wong TW, Tong HK, Lo CB, Kan PG. Out-of-hospital
cardiac arrest in Hong Kong. Prehosp Emerg Care
2001;5:308-11. Crossref
29. Wai AK, Cameron P, Cheung CK, Mak P, Rainer TH. Out-of-hospital cardiac arrest in a teaching hospital in Hong
Kong: descriptive study using the Utstein style. Hong Kong
J Emerg Med 2005;12:148-55.
30. Lau CL, Lai JC, Hung CY, Kam CW. Outcome of out-of-hospital
cardiac arrest in a regional hospital in Hong Kong.
Hong Kong J Emerg Med 2005;12:224-7.
31. Leung KL, Lui CT, Cheung KH, Tsui KL, Tang YH.
Outcome and prognostic factors of patients in out-of-hospital
cardiac arrests presenting with non-shockable
rhythm in Hong Kong. Hong Kong J Emerg Med 2012;19:6-12.
32. Chan TH, Lui CT, Cheung KH, Tang YH, Tsui KL. Outcome
predictors of patients in out-of-hospital cardiac arrests
with pre-hospital defibrillation in Hong Kong. Hong Kong
J Emerg Med 2013;20:131-7.
33. Fan KL, Leung LP. Prognosis of patients with ventricular
fibrillation in out-of-hospital cardiac arrest in Hong Kong:
prospective study. Hong Kong Med J 2002;8:318-21.
34. Lui JC. Evaluation of the use of automatic external
defibrillation in out-of-hospital cardiac arrest in Hong
Kong. Resuscitation 1999;41:113-9. Crossref
35. Chair SY, Hung MS, Lui JC, Lee DT, Shiu IY, Choi KC.
Public knowledge and attitudes towards cardiopulmonary
resuscitation in Hong Kong: telephone survey. Hong Kong
Med J 2014;20:126-33.
36. Cheung BM, Ho C, Kou KO, et al. Knowledge of
cardiopulmonary resuscitation among the public in Hong
Kong: telephone questionnaire survey. Hong Kong Med J
2003;9:323-8.
37. Ringh M, Herlitz J, Hollenberg J, Rosenqvist M, Svensson L.
Out of hospital cardiac arrest outside home in Sweden,
change in characteristics, outcome and availability for
public access defibrillation. Scand J Trauma Resusc Emerg
Med 2009;17:18. Crossref
38. Atkins DL. Public access defibrillation: where does it work?
Circulation 2009;120:461-3. Crossref
39. The University of Hong Kong. Technology Enhanced
Learning Initiatives (TELI). Available from: http://teli.hku.hk/portfolio/aed-locator-app/. Accessed 1 Mar 2017.
40. Ho CL, Lui CT, Tsui KL, Kam CW. Investigation of
availability and accessibility of community automated
external defibrillators in a territory in Hong Kong. Hong
Kong Med J 2014;20:371-8.
41. Mitamura H. Public access defibrillation: advances from
Japan. Nat Clin Pract Cardiovasc Med 2008;5:690-2. Crossref
42. Singapore Civil Service College. SCDF’s myResponder App
helps saves lives. Available from: https://www.cscollege.gov.sg/Knowledge/Pages/SCDF-myResponder-App-Helps-Saves-Lives.aspx. Accessed 5 Jul 2017.
43. Herlitz J, Ekström L, Wennerblom B, Axelsson A, Bång A,
Holmberg S. Type of arrhythmia at EMS arrival on scene
in out-of-hospital cardiac arrest in relation to interval from
collapse and whether a bystander initiated CPR. Am J
Emerg Med 1996;14:119-23. Crossref