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Resuscitation
96
(2015)
53–58
Contents
lists
available
at
ScienceDirect
Resuscitation
jou
rn
al
hom
ep
age
:
w
ww.elsevier.com/locate/resuscitation
Clinical
paper
Public
Access
Defibrillation:
Great
benefit
and
potential
but
infrequently
used夽
Marianne
Agerskova,∗,
Anne
Møller
Nielsena,b,
Carolina
Malta
Hansenc,
Marco
Bo
Hansena,
Freddy
Knudsen
Lippertb,
Mads
Wissenbergb,c,
Fredrik
Folkeb,c,
Lars
Simon
Rasmussena
aDepartment
of
Anaesthesia,
Centre
of
Head
and
Orthopaedics,
Rigshospitalet,
University
of
Copenhagen,
Blegdamsvej
9,
2100
Copenhagen,
Denmark
bThe
Emergency
Medical
Services,
The
Capital
Region
of
Denmark
and
Copenhagen,
University
of
Copenhagen,
Copenhagen,
Denmark
cDepartment
of
Cardiology,
Gentofte
Hospital,
University
of
Copenhagen,
Copenhagen,
Denmark
a
r
t
i
c
l
e
i
n
f
o
Article
history:
Received
24
April
2015
Received
in
revised
form
18
July
2015
Accepted
22
July
2015
Keywords:
Out-of-hospital
cardiac
arrest
Public
Access
Defibrillation
Survival
Automated
external
defibrillation
Cardiopulmonary
resuscitation
Defibrillators
a
b
s
t
r
a
c
t
Background:
In
Copenhagen,
a
volunteer-based
Automated
External
Defibrillator
(AED)
network
provides
a
unique
opportunity
to
assess
AED
use.
We
aimed
to
determine
the
proportion
of
Out-of-Hospital
Cardiac
Arrest
(OHCA)
where
an
AED
was
applied
before
arrival
of
the
ambulance,
and
the
proportion
of
OHCA-cases
where
an
accessible
AED
was
located
within
100
m.
In
addition,
we
assessed
30-day
survival.
Methods:
Using
data
from
the
Mobile
Emergency
Care
Unit
and
the
Danish
Cardiac
Arrest
Registry,
we
identified
521
patients
with
OHCA
between
October
1,
2011
and
September
31,
2013
in
Copenhagen,
Denmark.
Results:
An
AED
was
applied
in
20
cases
(3.8%,
95%
CI
[2.4
to
5.9]).
Irrespective
of
AED
accessibility,
an
AED
was
located
within
100
m
of
a
cardiac
arrest
in
23.4%
(n
=
102,
95%
CI
[19.5
to
27.7])
of
all
OHCAs.
However,
at
the
time
of
OHCA,
an
AED
was
located
within
100
m
and
accessible
in
only
15.1%
(n
=
66,
95%
CI
[11.9
to
18.9])
of
all
cases.
The
30-day
survival
for
OHCA
with
an
initial
shockable
rhythm
was
64%
for
patients
where
an
AED
was
applied
prior
to
ambulance
arrival
and
47%
for
patients
where
an
AED
was
not
applied.
Conclusions:
We
found
that
3.8%
of
all
OHCAs
had
an
AED
applied
prior
to
ambulance
arrival,
but
15.1%
of
all
OHCAs
occurred
within
100
m
of
an
accessible
AED.
This
indicates
the
potential
of
utilising
AED
networks
by
improving
strategies
for
AED
accessibility
and
referring
bystanders
of
OHCA
to
existing
AEDs.
©
2015
Elsevier
Ireland
Ltd.
All
rights
reserved.
1.
Introduction
Out-of-hospital
cardiac
arrest
(OHCA)
is
a
significant
health
problem
associated
with
cardiovascular
disease,
which
is
the
lead-
ing
cause
of
sudden
death.1,2 Early
defibrillation
is
essential
to
increase
survival
and
the
use
of
publicly
accessible
Automated
External
Defibrillators
(AED)
has
been
shown
to
increase
the
chances
of
survival
up
to
74%.3–9 Despite
initiatives
to
disseminate
AEDs
in
public
settings,
the
proportion
of
OHCA-victims
defibril-
lated
prior
to
arrival
of
the
Emergency
Medical
Services
(EMS)
is
夽A
Spanish
translated
version
of
the
summary
of
this
article
appears
as
Appendix
in
the
final
online
version
at
http://dx.doi.org/10.1016/j.resuscitation.2015.07.021.
∗Corresponding
author.
E-mail
address:
marianneagerskov@hotmail.com
(M.
Agerskov).
reported
to
be
less
than
3%
and
a
real
opportunity
to
save
lives
is
missed.9–11
The
European
Resuscitation
Council
and
the
American
Heart
Association
recommend
Public
Access
Defibrillation
(PAD)
pro-
grammes,
but
the
deployment
and
registration
of
AEDs
is
often
random
and
poorly
organized,
with
no
available
information
on
location
and
accessibility,
impeding
use
of
AEDs
by
bystanders
and
linkage
to
the
Emergency
Medical
Dispatch
Centre
(EMD).
In
Copenhagen,
the
capital
of
Denmark,
a
volunteer-based
AED
net-
work
has
been
established
with
validated
information
about
AED
location
and
accessibility.
The
network
is
linked
to
the
EMD
to
enable
guidance
to
nearest
accessible
AED
in
case
of
cardiac
arrest.
This
provides
a
unique
opportunity
to
assess
the
use,
effects,
and
coverage
of
PAD
as
the
network
also
allows
systematic
collection
of
data
from
applied
AEDs.
In
this
study,
we
aimed
to
determine
the
proportion
of
OHCA-
cases
where
an
AED
was
applied
prior
to
arrival
of
the
ambulance
http://dx.doi.org/10.1016/j.resuscitation.2015.07.021
0300-9572/©
2015
Elsevier
Ireland
Ltd.
All
rights
reserved.
54
M.
Agerskov
et
al.
/
Resuscitation
96
(2015)
53–58
and
the
proportion
of
OHCA-cases
where
the
EMD
referred
bystanders
to
an
AED.
In
addition,
we
sought
to
determine
the
pro-
portion
of
OHCA-cases
where
an
accessible
AED
was
located
within
100
m
at
the
time
of
the
cardiac
arrest.
Finally,
we
sought
to
eval-
uate
characteristics
and
survival
of
OHCA-victims
according
to
use
of
an
AED.
2.
Methods
2.1.
Study
setting
Copenhagen
is
the
capital
of
Denmark,
and
the
city
centre
com-
prises
94.9
km2with
a
population
of
661,461
people.
The
EMS
in
Copenhagen
is
a
2-tiered
system
comprising
ambu-
lances
providing
life
support
including
use
of
defibrillators,
and
physician-staffed
mobile
emergency
care
units
providing
addi-
tional
advanced
life
support.
In
the
event
of
a
cardiac
arrest,
both
tiers
of
response
are
activated
simultaneously.
Data
from
each
car-
diac
arrest
are
systematically
and
prospectively
recorded
by
the
physician
at
the
scene
and
entered
into
a
database
maintained
by
the
EMS
in
Copenhagen.
Additionally,
ambulance
personnel
are
required
to
complete
documentation
for
the
National
Danish
Car-
diac
Arrest
Registry
for
every
resuscitation-attempted
OHCA.
2.2.
AED
network
In
2007,
the
private
foundation
TrygFonden
established
an
online
network
(http://www.hjertestarter.dk/Service-Pages/
InEnglish)
in
which
registration
of
both
private
and
public
AEDs
is
voluntary
but
recommended
by
the
Danish
Health
and
Medicines
Authority
and
AED-vendors.
The
network
provides
detailed
infor-
mation
about
AED
location
(exact
address)
and
accessibility,
including
hours
when
the
AED
is
available,
as
described
in
detail
elsewhere.12 The
EMDs
across
the
country
have
implemented
an
IT-solution
based
on
the
AED
network,
enabling
them
to
refer
a
bystander
to
the
nearest
accessible
AED
in
the
event
of
suspected
OHCA.
When
an
emergency
call
is
received
and
the
location
is
deter-
mined,
the
medical
dispatcher
is
provided
with
a
map
showing
the
accessible
AEDs
within
100
m,
thus
enabling
the
dispatcher
to
refer
a
bystander
to
the
nearest
AED.
If
only
one
bystander
is
present,
the
dispatcher
can
choose
to
contact
the
AED
location
and
have
the
AED
brought
to
the
scene
of
the
cardiac
arrest.
When
an
AED
is
referred
to
by
the
dispatcher,
an
e-mail
is
automatically
generated
and
sent
to
the
network
enabling
them
to
unsubscribe
the
AED
until
in
place
again.
Every
case
is
followed
up
by
an
e-mail
or
a
telephone
call
to
the
person
listed
as
responsible
for
the
AED
in
the
network,
thereby
validating
the
use
of
the
AED
related
to
an
OHCA.
On
January
2014,
850
AEDs
in
the
city
centre
of
Copenhagen
were
registered
on
the
webpage.
Systematic
follow-up
of
AEDs
applied
by
bystanders
in
Copen-
hagen
began
in
2011
as
part
of
a
project
on
systematic
downloading
of
AED
data.13 Each
time
an
AED
is
applied
by
a
bystander
prior
to
arrival
of
the
ambulance,
the
AED
is
brought
to
the
EMD
in
Copen-
hagen
in
order
to
retrieve
the
stored
data.
The
data
are
transmitted
to
the
admitting
hospital
and
the
AED
is
returned
to
the
owner.
2.3.
Study
population
and
data
collection
This
observational
study
evaluated
the
use
and
effects
of
PAD
in
the
city
centre
of
Copenhagen
from
October
1,
2011
through
September
31,
2013.
A
cardiac
arrest
was
defined
according
to
the
Utstein
criteria
for
laypersons
and
ambulance
personnel.14 All
cases
of
OHCA
were
included
in
the
final
analysis
when
a
clinical
con-
dition
of
cardiac
arrest
resulted
in
resuscitation
efforts
by
either
bystanders
or
ambulance
personnel.
We
excluded
cardiac
arrests
witnessed
by
ambulance
personnel
as
this
study
focused
on
PAD.
Reporting
was
done
in
accordance
with
the
Utstein
template
for
reporting
OHCA.14
For
this
study
we
included
information
on
date,
time,
loca-
tion
of
arrest
(home
vs.
public
location,
the
latter
defined
as
all
areas
accessible
to
the
general
public),
exact
address
of
cardiac
arrest,
witnessed
or
not,
whether
the
bystander
performed
car-
dio
pulmonary
resuscitation
(CPR),
defibrillated
the
victim
or
both,
first
recorded
cardiac
rhythm,
ambulance
response
time
(inter-
val
between
call
to
the
EMD
and
ambulance
arrival),
survival
to
hospital,
and
30-day
survival.
Information
regarding
referral
of
bystanders
to
the
nearest
accessible
AED
by
the
EMD
was
col-
lected
from
the
online
AED
network.
Data
regarding
use
of
AEDs
(defined
as
AED
applied
to
a
patient
prior
to
ambulance
arrival)
were
obtained
from
the
EMD
and
validated
through
prehospital
medical
records.
Information
on
30-day
survival
was
obtained
from
the
Danish
Civil
Registration
System,
which
assigns
all
Danish
cit-
izens
a
civil
registration
number,
a
unique
personal
identification
number.
Exact
geographical
location
of
OHCAs
and
AEDs
was
determined
using
a
geographic
information
system
(QGIS,
http://www.qgis.
org/en/site).
Each
location
was
geocoded
to
the
street
level
based
on
the
address
of
the
incident
and
it
was
verified
that
each
cardiac
arrest
occurred
in
the
city
centre
of
Copenhagen.
The
geocoding
process
assigns
a
latitude
and
longitude
coordinate
to
each
address.
An
AED
was
considered
to
cover
an
area
within
100
m,
based
on
the
estimate
that
an
AED
within
that
range
could
be
transported
by
bystanders
to
the
victim
within
1.5
min,
in
accordance
with
the
American
Heart
Association
recommendations.15
2.4.
Ethics
The
study,
and
the
processing
of
personal
data,
was
approved
by
the
Danish
Health
and
Medicines
Authority
(J.
nr.
3-3015-560/1)
and
the
Danish
Data
Protection
Agency
(J.
nr.
30-1223).
Ethical
approval
is
not
required
for
registry-based
studies
in
Denmark.
2.5.
Statistics
Continuous
variables
are
presented
as
median
with
their
asso-
ciated
inter
quartile
range
[IQR].
A
Mann–Whitney
test
was
used
for
comparisons
between
the
groups.
Categorical
data
are
reported
as
absolute
number
with
proportion
and
comparisons
were
done
using
Fisher’s
exact
test.
All
analyses
were
performed
using
the
SAS
Enterprise
Guide
statistical
software
package,
version
6.1
(SAS
Institute
Inc.,
Cary,
NC,
USA).
For
all
analysis,
a
2-sided
value
of
p
<
0.05
was
considered
statistically
significant.
3.
Results
A
total
of
2075
cases
of
OHCA
were
recorded
by
the
mobile
emergency
care
unit
in
the
city
centre
of
Copenhagen
during
the
study
period.
Of
these,
1476
cases
were
excluded
because
resus-
citation
was
not
attempted.
Five
OHCA-cases,
which
were
not
registered
with
the
EMD,
were
found
in
the
Danish
Cardiac
Arrest
Registry.
We
identified
604
OHCA-victims,
in
whom
resuscitation
was
attempted,
corresponding
to
an
all-cause
OHCA
incidence
of
46
OHCA
per
100,000
person
years.
For
further
analysis,
we
included
521
resuscitation-attempted
OHCAs
as
83
cases
(mainly
EMS-witnessed
OHCAs)
were
excluded
(Fig.
1).
An
AED
was
applied
prior
to
ambulance
arrival
in
20/521
(3.8%,
95%
CI
[2.4
to
5.9])
cases
and
13/521
(2.5%,
95%
CI
[1.3
to
4.2])
OHCA-
victims
were
defibrillated
by
an
AED.
M.
Agerskov
et
al.
/
Resuscitation
96
(2015)
53–58
55
Fig.
1.
Patient
flow,
October
1,
2011–September
31,
2013.
A
total
of
22
publicly
accessible
AEDs
in
the
city
centre
of
Copen-
hagen
had
ECG-data
downloaded,
but
two
patients
did
not
have
OHCA.
3.1.
Characteristics
of
OHCA-victims
OHCA-cases
who
had
an
AED
applied
prior
to
ambulance
arrival
occurred
significantly
more
often
in
public
places
(79%
vs.
32%,
p
≤
0.0001)
and
they
had
a
significantly
higher
proportion
of
bystander
CPR
(95%
vs.
60%,
p
=
0.0014)
and
initial
shockable
rhythm
(74%
vs.
27%,
p
≤
0.0001)
(Table
1).
The
proportion
of
bystander
witnessed
cardiac
arrest
and
the
ambulance
response
time
were
not
significantly
different,
nor
was
there
any
significant
differences
in
age
or
sex
according
to
AED
application.
There
were
no
differences
in
the
proportion
of
OHCA-cases
where
an
AED
was
applied
according
to
the
time
of
day.
3.2.
AED-referral
Bystanders
were
referred
to
an
AED
by
the
EMD
in
20
cases
but
an
AED
was
only
applied
in
six
of
these
(30%)
cases
prior
to
ambu-
lance
arrival.
In
14
cases,
an
AED
was
retrieved
spontaneously
by
a
bystander
and
applied
to
an
OHCA-victim
prior
to
ambulance
arrival.
There
were
no
differences
in
patient
characteristics
and
survival
according
to
AED-reference
(Table
2).
3.3.
AED
coverage
and
potential
Exact
geographical
location
of
436
(84%)
OHCAs
was
success-
fully
determined.
Irrespective
of
AED
accessibility,
an
AED
was
located
within
100
m
of
a
cardiac
arrest
in
23.4%
(n
=
102,
95%
CI
[19.5
to
27.7])
of
all
OHCAs.
At
the
time
of
cardiac
arrest,
an
AED
was
located
within
100
m
and
accessible
in
15.1%
(n
=
66,
95%
CI
[11.9
to
18.9])
of
all
cases,
but
only
10.6%
(n
=
7,
95%
CI
[4.9
to
20.6])
of
these
had
an
AED
applied.
In
13
cases,
an
AED
was
retrieved
more
than
100
m
from
the
location
of
the
cardiac
arrest.
Accordingly,
there
were
59
OHCA-cases
(11.3%
of
all
OHCA,
95%
CI
[8.7
to
14.4])
where
an
AED
could
have
been
referred
to
by
the
EMD
and
applied
prior
to
ambulance
arrival.
3.4.
Outcome
The
30-day
survival
for
non-shockable
OHCA
was
20%
for
patients
where
an
AED
was
applied
prior
to
ambulance
arrival
and
9%
for
patients
without
an
AED
applied,
p
=
0.37.
For
OHCA
with
an
initial
shockable
rhythm
30-day
survival
was
64%
for
patients
with
an
AED
applied
and
47%
for
patients
without
an
AED
applied,
p
=
0.26
(Table
3).
(Table
3)
4.
Discussion
In
this
study
of
a
volunteer-based
AED
network,
linked
to
the
EMD,
we
found
that
3.8%
of
all
OHCAs
had
an
AED
applied
prior
to
ambulance
arrival.
Almost
every
fourth
OHCA
had
an
AED
within
100
m,
however,
the
AED
was
only
accessible
at
the
time
of
cardiac
arrest
in
15.1%
of
the
cases
and
only
10.6%
of
these
had
an
AED
applied.
The
EMD
referred
a
bystander
to
the
nearest
accessible
AED
in
2.3%
of
all
OHCA-cases.
OHCA
with
an
AED
applied
prior
to
ambulance
arrival
occurred
more
often
in
public
locations,
these
patients
received
more
often
bystander
CPR
and
they
had
a
larger
proportion
of
initial
shockable
rhythm.
The
main
strength
of
this
study
is
that
we
describe
several
aspects
of
the
use
of
a
volunteer-based
AED
network
with
vali-
dated
information
on
location
and
accessibility.
Thus,
we
were
able
to
describe
independent
retrieval
and
use
of
AEDs
by
bystanders,
AED
coverage,
AED
use
by
bystanders
through
EMD-referral,
and
ECG-data
from
applied
AEDs.
Most
PAD
studies
only
report
data
from
shockable
OHCAs
thereby
probably
underestimating
the
use
of
AEDs.5,16
The
potential
of
PAD
in
the
city
centre
of
Copenhagen
was
assessed
through
identification
of
all
accessible
AEDs
within
100
m
from
the
OHCA.
Several
limitations
must
be
mentioned.
AED
placement
is
decided
solely
by
the
AED
owner
and
accordingly,
the
AED
dis-
tribution
is
random.
This
study
does
not
allow
any
changes
in
the
locations
of
the
AEDs
and
is
therefore
not
designed
for
analysing
AED
placement
and
coverage,
but
rather
for
assessing
the
proba-
bility
of
having
a
nearby
AED
accessible
in
case
of
OHCA.
Regarding
EMD-reference
of
AEDs,
the
linkage
between
a
referral
and
an
OHCA-victim
presents
a
challenge,
as
it
is
not
registered
when
the
dispatcher
refers
to
an
AED.
The
only
information
available
was
56
M.
Agerskov
et
al.
/
Resuscitation
96
(2015)
53–58
Table
1
Out-of-hospital
cardiac
arrest
in
Copenhagen
from
October
1,
2011
through
September
31,
2013.
AED:
Automated
External
Defibrillator,
IQR:
inter
quartile
range,
CPR:
Cardiopulmonary
Resuscitation.
AED
applied
prior
to
ambulance
arrival
(n
=
20)*AED
not
applied
prior
to
ambulance
arrival
(n
=
501)*p
Value
Age,
median
(IQR),
y73
(65–82) 67
(54–79) 0.34
Men,
n
(%)
12
(80.0)
301
(61.8)
0.18
Time
of
daya0.49
Daytime,
n
(%)
9
(45.0)
236
(48.1)
Evening,
n
(%)
9
(45.0)
162
(33.0)
Night
time,
n
(%)
2
(10.0)
93
(18.9)
Public
location,
n
(%)b15
(79.0)
117
(32.2)
<0.0001
Response
time,
median
(IQR),
(min)c5
(4–6) 5
(4–7) 0.29
Bystander
witnessed,
n
(%)
15
(79.0)
224
(61.7)
0.15
Bystander
CPR,
n
(%)
18
(94.7)
219
(60.3)
0.0014
Shockable
rhythm,
n
(%)d14
(73.7)
98
(27.0)
<0.0001
*Number
of
patients
with
missing
value
for
the
variables
bystander
witnessed,
bystander
CPR
and
public
location:
“AED
applied
prior
to
ambulance
arrival”
n
=
1
and
“AED
not
applied
prior
to
ambulance
arrival”
n
=
138.
aDaytime,
evening
and
night
time
defined
as
8
am
to
3:59
pm,
4
to
11:59
pm,
and
midnight
to
7:59
am.
bPublic
location
defined
as
all
areas
accessible
to
the
general
public
all
hours
all
day.
cInterval
between
call
to
the
EMS
and
ambulance
arrival.
dFirst
recorded
rhythm.
Table
2
AEDs
applied
prior
to
ambulance
arrival
in
Copenhagen
from
October
1,
2011
through
September
31,
2013.
EMD:
Emergency
Medical
Dispatch
Centre,
IQR:
inter
quartile
range,
CPR:
cardiopulmonary
resuscitation.
Referred
by
EMD
(n
=
6)
Not
referred
by
EMD
(n
=
14)*p
Value
Age,
median
(IQR),
y
73
(68–73)
73
(65–83)
0.62
Men,
n
(%)
4
(80.0)
7
(77.8)
1.0
Time
of
daya0.35
Daytime,
n
(%)
4
(66.7)
5
(38.5)
Evening
and
night
time
n
(%) 2
(33.3) 8
(61.5)
Public
location,
n
(%)b6
(100)
9
(69.2)
0.26
Response
time,
median
(IQR),
(min)c4
(3–5)
5
(4–5)
0.25
Bystander
witnessed,
n
(%)
5
(83.3)
10
(76.9)
1.0
Bystander
CPR,
n
(%)
6
(100)
12
(92.3)
1.0
Shockable
rhythm,
n
(%)d5
(83.3)
9
(69.2)
1.0
30-Day
survival,
n
(%)
Non-shockable
rhythme0
(0)
1
(20.0)
1.0
Shockable
rhythmf5
(71.4)
10
(83.3)
0.6
*Number
of
patients
with
missing
value
for
the
cardiac
arrest-related
variables:
bystander
witnessed,
bystander
CPR
and
public
location
n
=
1.
aDaytime,
evening
and
night
time
defined
as
8
am
to
3:59
pm,
4
to
11:59
pm,
and
midnight
to
7:59
am.
bPublic
location
defined
as
all
areas
accessible
to
the
general
public
all
hours
all
day.
cInterval
between
call
to
the
EMS
and
ambulance
arrival.
dFirst
recorded
rhythm.
eNon-shockable
rhythm:
Asystole
or
pulseless
electrical
activity.
fShockable
rhythm:
ventricular
fibrillation
or
pulseless
ventricular
tachycardia.
the
location
of
AED
and
the
time
of
reference.
In
this
study,
almost
half
of
the
referred
AEDs
could
not
be
connected
to
an
OHCA-case,
which
means
that
we
have
no
knowledge
of
the
nature
of
these
referrals,
or
if
the
case
was
in
fact
an
OHCA.
Additionally,
we
could
only
include
information
about
AEDs
with
downloaded
ECG-data
and
AEDs
may
have
been
applied
with-
out
any
ECG
data
being
retrieved
if
the
AED
was
not
brought
to
the
EMD
after
OHCA.
In
Denmark,
a
nationwide
study
reports
that
2.2%
of
all
OHCA-
cases
were
defibrillated
prior
to
ambulance
arrival
in
2010.11 We
found
an
increased
use
of
PAD,
which
might
reflect
several
ini-
tiatives
taken
to
raise
survival
after
OHCA
in
Denmark
during
recent
years
including;
implementation
of
mandatory
resuscitation
training
in
elementary
schools
and
when
acquiring
a
driver’s
licence,
improving
the
telephone
guidance
to
bystanders
witness-
ing
a
cardiac
arrest
by
implementation
of
health
care
professionals
at
the
EMDs,
and
finally
there
has
been
a
large
increase
in
the
num-
ber
of
public
accessible
AEDs.11,12 Furthermore,
we
report
AED
use
in
the
city
centre
of
Copenhagen
where
AED
coverage
is
higher
than
in
more
rural
parts
of
the
country.
A
study
conducted
on
the
Dan-
ish
rural
island
of
Bornholm
showed
that
an
AED
was
applied
to
an
OHCA-victim
in
10%
of
all
OHCA-cases
after
an
intervention
com-
prising
mass
education
in
basic
life
support
(BLS)
and
a
television
campaign.17 The
same
study
group
showed
that
the
willingness
Table
3
Outcome
in
OHCA
patients
in
the
city
centre
of
Copenhagen
2013
from
October
1,
2011
through
September
31,
2013.
OHCA:
out-of-hospital
cardiac
arrest,
AED:
Automated
External
Defibrillator.
AED
applied
prior
to
ambulance
arrival
AED
not
applied
prior
to
ambulance
arrival
p
Value
30-Day
survival,
n
(%)
Non-shockable
rhythma1
(20%,
95%
CI
[0.5–72])
23
(9%,
95%
CI
[613])
0.37
Shockable
rhythmb9
(64%,
95%
CI
[35–87])
46
(47%,
95%
CI
[37–57])
0.26
aNon-shockable
rhythm:
Asystole
or
pulseless
electrical
activity.
bShockable
rhythm:
ventricular
fibrillation
or
pulseless
ventricular
tachycardia.
M.
Agerskov
et
al.
/
Resuscitation
96
(2015)
53–58
57
to
use
an
AED
increased
significantly
following
the
intervention,
suggesting
a
way
of
creating
awareness
through
education
and
information
thereby
increasing
the
use
of
PAD,
as
also
described
in
other
studies.18–21
Several
aspects
should
be
considered
to
further
improve
AED
use.
Since
most
cardiac
arrests
occur
in
residential
areas,
first
responder
programs
may
enhance
PAD.
Studies
in
Hol-
land
and
Sweden
have
demonstrated
high
survival
rates
in
association
with
structured
AED
programs
as
well
as
spread
of
unregulated
AEDs.22,23 Nearby
lay-first
responders,
as
part
of
a
structured
AED
program,
are
dispatched
through
a
text-message,
thereby
shortening
time
to
defibrillation.24,25 In
addition,
firefighters
equipped
with
AEDs
can
be
dispatched
in
the
event
of
OHCA
and
this
has
been
shown
to
increase
survival.26
Linkage
between
the
AED-network
and
the
EMD
is
essential
but
there
may
be
a
mismatch
between
the
time
of
cardiac
arrest
and
the
accessibility
of
the
AEDs.27
Finally,
identification
of
OHCA
by
the
dispatcher
represents
a
challenge
in
itself
in
order
to
refer
a
bystander
to
an
AED.28,29
Means
to
increase
AED
utilisation
should
target
public
aware-
ness
of
the
AED
network
and
the
location
of
the
AEDs,
CPR
and
AED
training,
and
further
development
of
the
existing
AED
network
and
linkage
to
the
EMD
with
special
attention
on
placing
AEDs
outside,
providing
accessibility
at
all
times.
Two
studies
assessing
the
AED
coverage
of
public
OHCA
in
the
city
centre
of
Copenhagen
between
1994
and
2011
showed
AED
coverage
of
28.8%
of
all
public
OHCAs
regardless
of
AED
accessibility
and
an
increase
in
AED
coverage
from
2.7%
to
32.6%
over
a
5-year
period,
respectively.12,27 We
found
a
slightly
smaller
AED
coverage
of
OHCA,
most
likely
due
to
the
fact
that
we
included
OHCAs,
which
happened
in
private
homes.
We
found
no
differences
in
patient
characteristics
and
out-
comes
according
to
EMD-reference,
but
we
only
included
OHCAs
in
an
urban
area
where
EMS
response
time
is
relatively
short.
Ref-
erence
to
nearby
AEDs
might
have
greater
impact
in
rural
areas
with
longer
response
time.
Initiatives
should
be
taken
to
optimize
EMD-reference
to
nearby
AEDs
and
to
register
referred
AEDs
in
con-
nection
to
OHCA-victims.
Additionally,
initiative
should
be
taken
to
enhance
retrieval
of
all
applied
AEDs.
Due
to
the
small
number
of
observations
in
this
study,
we
were
not
able
to
detect
a
significant
increase
in
survival
when
layper-
sons
use
an
AED.
However,
the
tendency
towards
an
increase
in
30-day
survival
is
important
as
survival
rates
after
OHCA
in
gen-
eral
are
low.2,3,30 The
association
between
PAD
and
survival
is
in
accordance
with
other
studies.5,7,16
There
may
be
other
reasons
for
the
tendency
towards
a
high
sur-
vival
rate.
First,
other
studies
have
shown
that
a
high
proportion
of
publicly
accessible
AEDs
are
placed
in
sports
facilities
where
vic-
tims
in
general
may
be
healthier.4,27 Second,
bystanders
at
these
facilities
are
more
likely
to
be
trained
to
perform
BLS
as
courses
are
often
offered
by
the
sports
clubs
and
the
AED
vendors.
We
are
aware
that
in
order
to
correlate
AED
use
and
survival,
it
would
have
been
relevant
to
perform
an
analysis
with
adjustments
for
confound-
ing
factors
such
as
bystander
CPR
however,
this
was
not
possible
due
to
the
small
proportion
of
OHCA
with
an
AED
applied
before
ambulance
arrival.
We
found
a
significantly
higher
proportion
of
an
initial
shock-
able
rhythm
if
an
AED
was
applied
prior
to
ambulance
arrival.
This
is
important,
since
the
prevalence
in
general
is
only
approximately
25%,
which
could
potentially
jeopardize
the
concept
of
PAD.31–33
Our
findings
is
in
accordance
with
another
study
conducted
in
Copenhagen
which
recently
showed
that
publicly
accessible
AEDs
detected
an
initial
shockable
rhythm
in
55%
of
OHCA-cases
com-
pared
with
only
27.6%
in
the
cases
where
the
initial
rhythm
was
detected
by
the
EMS.13
5.
Conclusion
We
found
that
3.8%
of
all
OHCAs
had
an
AED
applied
prior
to
ambulance
arrival,
but
15.1%
of
all
OHCAs
occurred
within
100
m
of
an
accessible
AED.
This
indicates
the
potential
of
utilising
AED
networks
by
improving
strategies
for
AED
accessibility
and
refer-
ring
bystanders
of
OHCA
to
existing
AEDs.
Conflict
of
interest
statement
No
conflicts
reported.
Acknowledgements
Lars
Rasmussen
has
received
grants
from
TrygFonden.
Carolina
Malta
Hansen
has
re-received
funding
from
TrygFonden,
Helse-
fonden
and
Laerdal.
TrygFonden,
Helsefonden
or
Laerdal
have
not
taken
any
part
in
designing
the
study,
analysing
the
data
or
any
decision-making
regarding
the
manuscript.
Special
thanks
are
given
to
Martin
Fjordholt
and
Thomas
Kristian
Kristensen
for
help
with
data
acquisition
and
geocoding.
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