Circumstances and causes of sudden circulatory arrests in the Dutch province of Limburg and the involvement of citizen rescuers
Circumstances and causes of sudden circulatory arrests in the Dutch province of Limburg and the involvement of citizen rescuers
R. W. M. Pijls 0 1 2
P. J. Nelemans 0 1 2
B. M. Rahel 0 1 2
A. P. M. Gorgels 0 1 2
0 Department of Cardiology, Viecuri Medical Centre for Northern Limburg , Venlo , The Netherlands
1 Department of Epidemiology, CAPHRI school for Public Health and Primary Care, Maastricht University Medical Centre
2 Department of Cardiology, CAPHRI school for Public Health and Primary Care, Maastricht University Medical Centre
3 , Maastricht , The Netherlands
Background Recently we showed that a citizen volunteer system using text message alerts improves survival of outof-hospital sudden circulatory arrest (OHCA). It is important to characterise the OHCA population encountered by the volunteers regarding circumstances and causes of the arrests. Methods and Results Eligible for this study were 968 OHCAs that occurred between April 2012 and April 2014 in the Dutch province of Limburg. The distribution of causes of OHCA, patient characteristics and resuscitation settings were compared between 492 arrests wherein volunteers were notified and 476 arrests where the dispatcher decided not to do so. In case of notification, the cause of OHCA was known in 345 cases and of cardiac origin (treatable) in 83.2% (287/345). About 41% of the cardiac arrests were caused by acute or chronic coronary artery disease. OHCA occurred within the home environment in about 84%. The OHCA was witnessed in 75% of the cases. In 60.9% of the cases a witness or bystander had already started basic life support. However, in approximately 18% of the OHCAs the volunteer was the first to start basic life support before arrival of the ambulance. In about 75% of the OHCAs the ambulance arrived at 6 minutes or later after time of notification by the dispatch centre. Conclusion The volunteer system is predominantly activated in situations for which it was developed; cases with cardiac aetiology (58%) and cases in the home environment (84%). The majority of patients encountered by the volunteers had 'hearts too good to die', underscoring the benefit of deploying citizen rescuers in programs to improve survival of OHCA.
resuscitation; community responder; cause; circumstance
Recently we described that a novel citizen volunteers alert
system significantly contributes to survival of
out-of-hospital circulatory arrest (OHCA) of cardiac origin [
contribution of the alert system to survival is most
substantial in witnessed arrest, within the home environment,
at slightly delayed arrival of the first ambulance and during
the evening/night [
]. The zip-code based system was
developed especially for OHCA within the home environment,
enabling the dispatch centre to alert trained citizen rescuers
simultaneously with the ambulances. Involving citizens as
first responders in resuscitation of cardiac arrest, imposes
them with a large responsibility. It is therefore crucial to
study whether they indeed encounter emergency cases with
a reasonable chance to actually provide substantial support.
This depends mainly on the details of the resuscitation
scenario and the causes of the OHCA. It is therefore important
to explore if the volunteers are notified especially for
resuscitation settings within the home situation and for help
for OHCAs with a cardiac cause. This study aims to verify
that the alert system is deployed in conditions for which
it was initially developed by providing a description of the
circumstances and causes of OHCAs, specifically where the
citizen volunteers are involved.
We used data from a prospective registry consisting of
all OHCAs in the Dutch province of Limburg (an area
of approximately 2,153 km2 (831mi2) with 1.12 million
inhabitants) during the period April 2012 to April 2014.
Utstein recommendations and definitions were used [
The medical ethics committee of the Maastricht
University Medical Centre approved the study (project number
Resuscitation volunteer network in the study region
As outlined elsewhere [
], the basic professional procedure
for an OHCA in the Netherlands consists of dispatching
two ambulances to the scene, both manned by a paramedic
and a basic life support (BLS)/automated external
defibrillator (AED) trained driver, equipped with a defibrillator
and requirements to provide advanced life support.
Furthermore, the dispatch centralist can choose to activate the
citizen volunteer system, a system where certified BLS/AED
volunteers are notified by a text message. The dispatch
centralist does not activate the system if the ambulance is
already nearby or present at the scene, if the OHCA occurs in
a (closed) public place with an on-site AED (such as
shopping malls, sport venues etc.), if the OHCA is evidently of
a non-cardiac aetiology or if the need for resuscitation is
not recognised. The system uses the zip codes of the
location of the victim and citizen rescuers to determine which
volunteers are possibly closest to the victim, at least within
a radius of 1 km (0.62 mile). In a 1:2 fashion, selected
volunteers are notified to either go to the victim immediately
or collect a system-registered AED first. To ensure a
sufficient, but not excessive, number of volunteers, a maximum
of 30 citizen rescuers are notified.
At the time of the study, 17 of the 24 dispatch centres in
the Netherlands were using the system. In Limburg, both
dispatch centres were active with a total of >9,000
volunteers (8.3/1,000 inhabitants).
We retrieved data from the following sources: 1. the
dispatch centres from Limburg North and South, 2. their
respective emergency medical services, 3. notified volunteers,
4. alert system organisation (Hartslagnu), 5. the six
hospitals in Limburg, and 6. AED providers.
All notified volunteers received a questionnaire to
obtain information about their attendance and, if applicable,
about details of the resuscitation scenario. Medical history
and post-resuscitation treatment were provided by the six
hospitals in Limburg.
We assessed causes of OHCAs using information mostly
from hospital records and discharge reports, autopsy
reports, as well as from written information from the dispatch
centre and ambulance personnel. All diagnoses were
confirmed by one of the authors, a senior cardiologist (A.G.).
Acute coronary syndromes were cases with documented
ST-elevation myocardial infarction or non-ST-elevation
myocardial infarction. Cases with previous coronary
revascularisation or old myocardial infarction were diagnosed
as chronic coronary artery disease. Electrical heart
diseases included tachycardia, mostly of ventricular origin;
bradycardia, either unspecified or due to sinus
bradycardia or atrioventricular block, or genetic forms such as
Wolff-Parkinson-White, Brugada or long QT-syndrome.
Structural heart disease consisted mostly of cases with
hypertrophic or dilated cardiomyopathy. The diagnosis
exsanguination included cases such as ruptured dissection/
aneurysm or gastrointestinal bleed, and asphyxia was
diagnosed in cases with respiratory insufficiency, pulmonary
embolism or suffocation, mostly by choking.
The distribution of causes of OHCA, patient characteristics
and resuscitation settings were evaluated in the group of
OHCAs in which the system was activated and compared
with distribution in the group of OHCAs in which the
system was not activated. Categorical variables were described
as absolute numbers and percentages, and continuous
variables as means with standard deviation or medians with
interquartile range. The chi-square test was used to test
for statistically significant differences in proportions
between groups. For comparison of differences in continuous
variables the t-test for independent samples or the
MannWhitney U test were used.
We used the statistical software package of SPSS (SPSS
for Windows, version 22.0, SPSS Inc., Chicago, IL) to
analyse the data.
1085 resuscitation attempts
461 prolonged death
32 within the ambulance
85 with an on-site CPR infrastructure
system not activated
During the 24 months study period, 1,546 OHCAs were
recorded. There were 461 victims with prolonged death
and a resuscitation setting was present in 1,085 victims
(including non-cardiac arrests and cases with a
do-not-resuscitate policy). Arrests within the ambulance occurred in
32 instances. A total of 85 OHCAs occurred in closed
public places with an on-site AED and local trained rescuers.
Therefore, 968 cases were included for evaluation of causes
of OHCA, patient characteristics and resuscitation settings
in the OHCA population as encountered by the citizen
rescuers. The system was activated in 492 arrests (50.8%) and
not activated in 476 arrests (49.2%), as depicted in Fig. 1.
Involvement of text message responders
Tab. 1 shows the baseline characteristics per scenario
(activated versus not activated). The mean age of patients with
OHCAs in which the system was activated was 67.9 (±14.1)
and around 70% was male, similar to the distribution of age
and sex in OHCAs in which the system was not activated.
Regarding circumstances of OHCAs, citizen rescuers
were more frequently involved in OHCAs within the home
environment compared with resuscitations outside the home
(83.9% vs 66.1%). A witness and/or bystander had already
started resuscitation in 60.9% of cases (versus 41% in
arrests where no volunteers were involved) and in
approximately 18% the volunteers were the first to start BLS. The
initial rhythm was shockable in 50% (versus 40.3% in
arrests without involvement of volunteers) and in the former
group also more frequently a shock was delivered.
Regarding the clinical setting of the OHCAs: in both
study groups the majority of cases were found to have no
cardiovascular history, thus the arrest being the first
manifestation of cardiovascular disease.
In cases where the system was activated, the first
ambulance arrived within 6 minutes in a mere 25% of cases.
Delay between 6–11 minutes was recorded in approximately
50% and delay exceeding 11 minutes in approximately
25%. In the non-activated group the arrival times are
unreliable because frequently the ambulance was already heading
to the case before upscaling to the highest level of
emergency due to the OHCA occurring during the ride.
Because the system was developed particularly for the
treatment of arrests with a cardiac cause, we studied the
distribution of causes among the two different scenarios.
As expected, we found that citizen rescuers were more
frequently involved in OHCAs with a cardiac cause and less
frequently in cases with a non-cardiac cause. Cases were
classified as unknown (251 cases in total), mostly when
patients died before hospital arrival and no sufficient
diagnostic information could be obtained.
Information on cardiac and non-cardiac causes is listed
in Tab. 2. Basically, there were no differences in the
distribution of causes between the activated and the
nonactivated group. The cause of the arrest was known in
345 and 372 cases in the activated and non-activated
group, respectively. In 83.2% (287/345) of cases, volunteers
were confronted with OHCAs with a cardiac cause, many
being treatable. In a mere 16.8% (58/345), the OHCA was
non-cardiac. These proportions were 67.5% (251/372) and
32.5% (121/372) without activation of the system.
Acute (33.4%) and chronic (7.7%) coronary artery
disease were the most common cardiac causes. Heart failure
was noted in 12.9%. In 35.5%, the initial rhythm was
ventricular tachycardia (VT)/ventricular fibrillation (VF)
unspecified, mostly patients who died at the scene and no
further diagnostic information being available. Electrical and
structural heart diseases were encountered by volunteers in
10.5% (30/287) of the cardiac cases versus 14% in the
In the 58 cases with a non-cardiac cause in which
volunteers were involved, asphyxia (44.8%) was the most
frequent cause and exsanguination was diagnosed in 13.8%.
Trauma, drug overdoses and suicide were less likely to
occur in the activated group and there was no resuscitation
caused by submersion. Around 30% of the non-cardiac
cases in the activated group had other underlying causes
such as cerebral accidents or sepsis. In 3 cases in both
groups the initial rhythm was pulseless electrical activity
(PEA)/asystole, but the underlying causes could not be
BLS basic life support, CPR cardiopulmonary resuscitation, EMS emergency medical system, SD standard deviation, TM text message
aOn-duty police officer or firefighter notified to go to the resuscitation scene.
bPatients not being resuscitated because of a do-not-resuscitate policy
A population-based survey including all consecutive OHCAs
showed that the majority of cases involving volunteers had
a cardiac cause. In about 17% of cases with known
aetiology, cardiopulmonary resuscitation (CPR) was needed after
a collapse due to a non-cardiac cause. Treatable causes such
as acute coronary syndrome was the most common cardiac
cause. Around 60% of cases did not have a cardiovascular
history, the arrest being the first manifestation of cardiac
disease. This implies a good prognosis after successful
resuscitation in the majority of patients, a feature already
characterised in the early nineteen sixties as patients with
‘hearts too good to die’ [
Study population and involvement of the text message volunteer
The system has been shown to increase survival in cardiac
arrests if at least one volunteer responded [
]. In a
minority of cases volunteers are notified for non-cardiac
arrests, mostly due to asphyxia. In this situation, the
involvement of volunteers could also be lifesaving by applying
the Heimlich manoeuvre. Expectedly, volunteers are rarely
confronted with trauma-related OHCA because centralists
are instructed not to activate the system if the OHCA is
obviously caused by trauma.
Zip code information about the resuscitation location is
needed to activate the system, therefore OHCA occurring
within the home environment was predominant (occurring
in about 8 of 10 cases). Especially here support is needed
not only because of the frequent occurrence of OHCA at
home but also because of the more frequent absence of
adequate CPR capabilities in that situation. Given its
substantial contribution to survival, this system can be viewed
as a new link in the chain of survival.
In about 60% of the cases a witness or bystander had
already started BLS. Therefore, the system is helpful in
supporting lay providers faced with an OHCA situation. In
18% of cases the volunteers were the first to start BLS.
Although volunteers are BLS/AED certified, quick arrival
of the emergency medical services is mandatory. In over
75% of cases, the ambulance arrival time exceeded 6
minutes, underscoring the importance of this system as a bridge
to professional help. This is also supported by the higher
percentage of shockable rhythms with involvement of the
CPR cardiopulmonary resuscitation, PEA pulseless electrical activity, VT ventricular tachycardia, VF ventricular fibrillation
aIn 251 cases the cause was unknown and therefore these cases are not included in this table
bOther includes cases such as cerebral causes or sepsis
citizen rescuers, likely due to high quality BLS, helping to
sustain VT/VF, rather than this to deteriorate in asystole
In 42% of the OHCAs a volunteer alert would have
been appropriate, but the alert system was not activated.
The reasons why are currently being studied and are likely
due to circumstances such as: the ambulance was already
nearby or present at the scene, the OHCA occurred in an
enclosed public place with an on-site AED, the OHCA was
of a non-cardiac aetiology or the need for resuscitation was
Strengths and limitations
The strength of our study is that it concerns a
population-based survey, performed in a well-defined
geographical area, including all consecutive OHCA cases during a
2year period. Although we tried to obtain accurate
information from the notified volunteers by use of a questionnaire,
it was practically impossible, due to the rapidly changing
nature of a resuscitation setting, to retrieve exact numbers
of responders and their arrival times at the location.
From the hospital records we could assess the medical
history and the cause of the cardiac arrests of those being
admitted to the hospital. This was not possible in 251 cases
because these patients died at the scene. This limitation is of
course inherent to a medical emergency occurring outside
the hospital and with a low survival rate.
The majority of OHCAs encountered by volunteers occur
in the home environment, have a cardiac cause and involve
‘hearts too good to die’, underscoring the benefit of
deploying citizen rescuers in programs to improve survival of
Acknowledgements We are greatly indebted to the Province Limburg
and the Mercurius Foundation for the financial support of this study;
F.W. Lindemans and H.J.J. Wellens for their support and suggestions;
the staff of the participating hospitals, other institutions and medical
students for helping in collecting the data: Zuyderland hospital Sittard/
Heerlen; D. van Kraaij, H. Kragten and the R&D Cardiology;
Laurentius hospital Roermond, C. Werter and M. Janssen; Sint Jans Gasthuis
Weert, H. Klomps, and Viecuri Venlo; the emergency medical services
of the GGD South-Limburg (N. Otten) and AmbulanceZorg
LimburgNorth (L. Triepels), Hartslagnu and Ocean (T. Schrijnemaekers);
police department district Limburg South, AED solutions (R. Henderikx),
BHV-competent (J. Hoofs), Vivon (M. van Gorp †) and last but not
least, all volunteers helping to increase survival of their fellow citizens
with OHCA are gratefully acknowledged.
Funding This work was supported by the Province Limburg
[SAS202-01794] and the Mercurius Foundation, Heerlen [30957210N].
Conflict of interest R.W.M. Pijls, P.J. Nelemans, A.P.M. Gorgels and
B.M. Rahel declare that they have no competing interests.
Open Access This article is distributed under the terms of the
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