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O R I G I N A L R E S E A R C H Open Access
Functional outcome, cognition and quality of life
after out-of-hospital cardiac arrest and therapeutic
hypothermia: data from a randomized controlled
trial
Marjaana Tiainen
1*
, Erja Poutiainen
1,2
, Tuomas Oksanen
3
, Kirsi-Maija Kaukonen
3
, Ville Pettilä
3
, Markus Skrifvars
3
,
Tero Varpula
3
and Maaret Castrén
4,5
Abstract
Background: To study functional neurologic and cognitive outcome and health-related quality of life (HRQoL) in a
cohort of patients included in a randomised controlled trial on glucose control following out-of-hospital cardiac arrest
(OHCA) from ventricular fibrillation (VF) treated with therapeutic hypothermia.
Methods: Patients alive at 6 months after being discharged from the hospital underwent clinical neurological and
extensive neuropsychological examinations. Functional outcome was evaluated with the Cerebral Performance
Category scale, the modified Rankin scale and the Barthel Index. Cognitive outcome was evaluated by
neuropsychological test battery including two measures of each cognitive function: cognitive speed, execution,
memory, verbal skills and visuospatial performance. We also assessed quality of life with a HRQoL 15D questionnaire.
Results: Of 90 OHCA-VF patients included in the original trial, 57 were alive at 6 months. Of these, 52 (91%) were
functionally independent and 54 (95%) lived at their previous home. Focal neurological deficits were scarce. Intact
cognitive performance was observed in 20 (49%), mild to moderate deficits in 14 (34%) and severe cognitive deficits in 7
(17%) of 41 patients assessed by a neuropsychologist. Cognitive impairments were most frequently detected in executive
and memory functions. HRQoL of the CA survivors was comparable to that of age- and gender matched population.
Conclusions: Functional outcome six months after OHCA and therapeutic hypothermia was good in the great majority
of the survivors, and half of them were cognitively intact. Of note, the HRQoL of CA survivors did not differ from that of
age- and gender matched population.
Keywords: Cardiac arrest, Neurological outcome, Cognition, Quality of life, Hypothermia
Background
The prognosis of patients resuscitated from out-of-hospital
cardiac arrest (OHCA) with ventricular fibrillation (VF) as
the initial rhythm has improved, as up to 55% of
hypothermia-treated OHCA-VF patients may achieve good
outcome [1-3]. Long-term mortality among patients dis-
charged alive after OHCA does not differ markedly from
that of myocardial infarct (MI) patients without OHCA
[4]. In a recent study of Lindner and colleagues, the five-
year survival rate for OHCA patients discharged from hos-
pital alive was 75%, and the mean potential life-years saved
per patient was 22.8 years [5]. However, not only survival
but also functional outcome and quality of life are import-
ant long-term outcomes.
Neurologic outcome after CA is commonly evaluated by
Glasgow-Pittsburgh Cerebral Performance Categories
(CPC) [6,7]. This five-step category classification is simple,
but it has a limited value in discriminating between mild
and moderate brain injury [8]. Cognitive deficits may
markedly impair the functional status of CA survivors
and their quality of life. Regrettably, the CPC classification
does not comprise cognitive impairment in conscious
* Correspondence: marjaana.tiainen@hus.fi
1
Department of Neurology, Helsinki University Hospital, Haartmaninkatu 4,
Helsinki 00029, Finland
Full list of author information is available at the end of the article
© 2015 Tiainen et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain
Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article,
unless otherwise stated.
Tiainen et al. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine
(2015) 23:12
DOI 10.1186/s13049-014-0084-9
subjects, unless the impairment is severe. The increased
survival of OHCA-VF patients in the hypothermia-era
does not seem to be associated with decrease in survivors
with clinically significant cognitive deficits [9,10]. Compre-
hensive data on functional outcome of OHCA patients is
still limited. As the number of CA survivors is increasing,
there is clearly a need for data of their functional outcome
and quality of life.
Accordingly, we aimed to evaluate the functional
neurologic and cognitive outcome of hypothermia treated
OHCA-VF survivors and their quality of life in a cohort of
OHCA-VF patients included in a randomised controlled
trial on strict versus moderate glucose control.
Methods
This study protocol was approved by the ethics commit-
tee of the Helsinki University Central Hospital (HUCH).
All postresuscitation patients in the HUCH area with
witnessed OHCA caused by VF and admitted to the two
participating intensive care units (ICU) from November
2004 to December 2006 were screened for the SUGAR-
trial. The inclusion criteria were VF of presumed cardiac
origin, witnessed arrest, age ≥18 years, basic life support
(BLS) delay less than 15 min, return of spontaneous cir-
culation (ROSC) less than 35 min and unconsciousness
at hospital admission. Exclusion criteria were persistent
hypotension (mean arterial pressure below 65 mmHg for
over 30 min) despite therapy, pregnancy, terminal ill-
ness, pre-arrest illness limiting follow-up (eg. dementia),
or a do not attempt resuscitation order. After obtaining
informed consent from a close relative, patients were
randomized into a strict (4–6 mmol/l) or a moderate
(6–8 mmol/l) glucose control group for the first 48 hours
of treatment in the ICU. Short-acting insulin was used
in both groups as needed. All patients received thera-
peutic hypothermia of 33°C for 24 hours induced with
an intravascular cooling device (CoolGard, Zoll Medical
Corporation), followed by slow warming (warming rate
not exceeding 0.5°C per hour) to normothermia. General
treatment of the patients was conducted according to
the ICU’s written standard protocols. The delay from
discontinuation of sedative medication to recovery of
consciousness (defined as ability to obey verbal com-
mands) was recorded. The cause of CA was classified as
acute MI, myocardial ischemia without infarction, pri-
mary arrhythmia, or other. The short-term outcome of
the SUGAR-trial has been published previously [11].
Evaluation of outcome
All patients alive 6 months after CA were contacted and in-
vited for a follow-up visit. The evaluation at follow-up visit
included an interview and standard neurologic examination
performed by the same board certified neurologist (MT).
For institutionalized patients the assessment included also
an interview with the nearest relatives and/or with nursing
staff. The neurological outcome was also assessed by modi-
fied Rankin Scale (mRs) [12], Barthel Index (BI) [13], and
National Institutes of Health stroke scale (NIHSS) [14].
Cognitive outcome was evaluated by neuropsychological
examination including two measures of each cognitive
function: cognitive speed, execution, memory, verbal skills
and visuospatial performance. Health-related quality of life
(HRQoL) was assessed by the 15D questionnaire [15]. The
neurologist and the neuropsychologist performing the eval-
uationswereunawareofthepatient’s glucose treatment
group. If a patient was not able or not willing to attend a
follow-up visit, a telephone interview was performed, with
evaluation of CPC, BI and mRs.
Modified Rankin scale is a widely applied measure of
global disability and handicap after stroke [12]. The scores
for patients alive range from 0 (no symptoms) to 5 (bed-
ridden, incontinent, and requires constant nursing care
and attention). Favourable outcome in stroke studies is de-
fined as mRs 0-2 (0 = no symptoms at all, 1 = no signifi-
cant disability despite symptoms, 2 = slight disability;
independent but unable to carry out all previous activ-
ities). The Barthel Index is a measure to assess an individ-
ual's ability to perform activities of daily living related to
self-care and mobility; for example, transfers, stairs, feed-
ing, dressing, personal care and bathing [13]. The range of
functionally independent outcome is 95 to 100. BI score
90-55 indicates moderate dependency, and score 50-0 in-
dicates full dependency. NIHSS is a widely used instru-
ment for the evaluation of neurologic impairment after
stroke [14]. A 15-item scale provides a quantitative meas-
ure of the key components of a standard neurologic exam-
ination, with higher scores indicating greater impairment.
Neuropsychological examination was designed to esti-
mate cognitive functions sensitive to CA related cogni-
tive deficits. Different cognitive functions were measured
by the Similarities, Block Design and Digit Symbol sub-
tests of the Wechsler Adult Intelligence Scale-Revised
(WAIS-R), and by the Logical Passages subtask of the
Wechsler Memory Scale-Revised (WMS-R) and the List
Learning task of the WMS-III [15-17]. Furthermore, the
Trail-Making Test (Parts A and B), the Interference and
naming subtasks of the modified Stroop Test, semantic
fluency task (animal names) and visual search task were
used [18,19]. A patient’s test performance was catego-
rized as normal or impaired using the cut point of one
standard deviation (SD) below the mean of the Finnish
normative sample. If among the 10 tests none or only
one (≤10%) was impaired a subject’s cognitive perform-
ance was considered intact. When two to four tests (11-
49%) were below 1 SD cut point a cognitive functioning
was scored as mildly to moderately defective, and when
at least half of the tests (≥50%) were impaired it was
scored as severely defective.
Tiainen et al. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine (2015) 23:12 Page 2 of 7
15D is a generic, standardized, non-disease-specific
self-administered multidimensional measure of HRQoL
[20]. It has 15 dimensions: mobility, vision, hearing,
breathing, sleeping, eating, speech, elimination, usual
activities, mental function, discomfort and symptoms,
depression, distress, vitality and sexual activity. Each
dimension is divided into five grades of severity. The
15D can be used both as a profile and single index score
measure. The single index score, 15D score on a 0–1
scale, represents the overall HRQoL, and is calculated
from the health state descriptive system by using a set of
population-based preference or utility weights. The max-
imum score is 1 (no problems on any dimensions) and
the minimum score 0 (being dead). The minimal clinic-
ally significant difference in 15D is 0.03 [20]. The 15D
instrument has been tested in various states of illness,
e.g. in invasive treatment of coronary artery disease [21]
and stroke [22,23].
Statistical analysis
We present categorical variables as counts and percent-
ages, and non-normally distributed continuous data as
median and range, compared with the Mann-Whitney
U-test. We compared binary outcome data by Fisher’s
exact test. Correlations were analyzed by Spearman’srho-
test. Cognitive functions were analyzed using means and
standard deviations. P values < 0.05 were considered
statistically significant. We used the Statistica data
analysis software system® (StatSoft, Tulsa, OK, USA) to
analyze the data.
Results
At six months after CA, 57 patients (63%) of 90 patients
included in the study were alive and were contacted.
Outcome was assessed on a follow-up visit for 49 pa-
tients and by a phone interview for eight patients who
had no possibility for a visit (two living at a remote loca-
tion, three not willing to attend a visit, two patients not
being able to attend a visit due to other serious medical
conditions, one patient not speaking Finnish, Swedish
nor English interviewed by a translator). Figure 1 pre-
sents the flow-chart of study patients. The surviving pa-
tients were evaluated six to eight months (median
7.0 months) after the CA. Their clinical and demograph-
ical data are presented in Table 1. Diagnostic cardiologic
examinations and therapeutic interventions were com-
monly performed during the initial hospital stay. Coron-
ary angiography had been performed on 51 (89%)
patients, percutaneous coronary intervention (PCI) on
21 (37%) patients and coronary artery bypass grafting
(CABG) on 7 (12%) patients. Electrophysiological testing
had been performed on 17 (30%) patients and an im-
plantable cardioverter defibrillator (ICD) had been im-
planted in 19 (33%) of the 57 patients.
No difference was observed in the delay to recovery of
consciousness, CPC, cognitive outcome, NIHSS, mRs, BI
outcome or HRQoL between the strict and moderate
glucose groups (data not shown). Therefore we present
the outcome data as one group.
At evaluation after CA, CPC 1 outcome had been
achieved by 38 patients (42%), CPC 2 by 12 patients
(13%), and CPC 3 by 7 patients (8%). None of the pa-
tients were in persistent vegetative state (CPC 4), and 33
(37%) had died (CPC 5). Two patients with CPC 2 out-
come had already pre-arrest CPC of 2, and post-arrest
CPC 3 patients included one patient with a pre-arrest
CPC level of 3 and two patients with pre-arrest CPC of
2. Thus, favourable outcome after CA (CPC 1 or 2) was
observed in 50 (88% of 57 survivors and 56% of all 90
randomized patients). See Table 2 for additional data on
functional outcome.
The distribution of CPC, mRs, BI and NIHSS scores
among the survivors are presented as Figure 2. Median
[IQR] mRs score was 0 [0-2], median BI score 100 [100-
100] and median NIHSS score 0 [0-0]. Of 57 survivors,
the outcome was good in 52 (91%) by Barthel Index
(BI 95-100), and in 50 (88%) by mRS (mRS 0-2).
90 patients randomized to
SUGAR-trial
58 patients (64%) discharged
fro m hosp ital
32 patients (36%)
died during hospital
stay; six w ith
recovery of
consciousness
1 patient died before
six months
57 patients (63%) alive and
contacted six months after cardiac
arrest
8 patients with no
possibility to visit
evaluated by
telephone
49 patients attended
follow-up visit
41 patients attended
neuropsychological
examination
8 patients excluded
from
neuropsychological
examination:
3 refused, 5 with
interfer ing cond itions
Figure 1 Flow-chart of study patients.
Tiainen et al. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine (2015) 23:12 Page 3 of 7
Neurological sequels of CA were relatively few. Two
patients suffered also an ischemic stroke during the
hospitalization for CA, and one of them presented with
aphasia and apraxia with NIHSS score of 12. One patient
had been diagnosed with post-arrest epilepsy (secondar-
ily generalized seizures) and used antiepileptic medica-
tion with good seizure-control. Another patient had
experienced focal myoclonic jerks, which had spontan-
eously declined over time.
Neuropsychological examination could be performed
to 41 of the 49 patients attending follow-up visit (72% of
all 57 patients alive). Reasons for exclusion were chronic
conditions affecting cognitive skills (N = 4; two patients
with mental retardation, one patient with chronic
schizophrenia and one patient with frontal infarct not
able to co-operate), refusal (N = 3) and poor general con-
dition (N = 1). Of 41, 20 (49%) were cognitively intact,
14 (34%) had mild to moderate cognitive deficits and
severe cognitive deficits were found in 7 patients (17%).
Cognitive deficits were predominantly detected in execu-
tive and memory functions.
The 15D profile of studied patients compared to age-
and gender matched normal population sample (N = 5689)
is presented in Figure 3. The 15D total score of studied pa-
tients did not differ from the score of age- and gender
matched general population (0.883 vs 0.904, p = 0.112).
The scores for two dimensions, usual activities and sexual
activities, were significantly lower, whereas the score for
one dimension, discomfort and symptoms, was signifi-
cantly better than the respective scores in the general
population sample matched with the gender and age distri-
bution of the patients. Both mRs and CPC scores and clas-
sification by cognition correlated with self-assessed 15D
total score (for CPC r = -0.425, for mRs r = -0.574, for cog-
nition r = -0.317, p < 0.05). The 15D total score differed
significantly between patients with mRs 0 and 1 (me-
dian score 0.952 vs 0.851, p = 0.012), between mRs 0
and 2 (median score 0.952 vs 0.730, p = 0.003) and be-
tween 0 and 1-2 (median score 0.952 vs 0.840, p < 0.001).
The 15D total score difference was also significant be-
tween patients with CPC 1 and 2 (median score 0.939 vs
0.824, p = 0.017). However, the 15D total score did not dif-
fer between cognitively intact subjects and those with mild
to moderate cognitive deficits (0.952 vs 0.885, p = 0.323).
Discussion
We found that 91% of OHCA-VF patients surviving six
months after CA were functionally independent and
95% of survivors had been able to return to their home.
Table 1 Clinical and demographical data on patients alive
six months after out-of-hospital cardiac arrest (N = 57)
Age, years 59 (24-78)
Male 44 (77%)
Bystander initiated CPR 38 (67%)
BLS, min 8 (2-14)
ACLS, min 14.5 (6-100)
ROSC, min 17 (7-33)
Length of ICU stay, days 7 (3-38)
Serum NSE at 24 hours, mmol/L 16.0 (8.6-41.2)
Serum NSE at 48 hours, mmol/L 14.8 (6.8-33.1)
Delay to recovery of consciousness, days 1 (0-7)
The aetiology of cardiac arrest
Acute myocardial infarction 21 (37%)
Myocardial ischemia without infarction 11 (19%)
Arrhythmia 22 (39%)
Other 3 (5%)*
Pre-arrest medical history of
Coronary heart disease 13 (23%)
Acute myocardial infarction 10 (18%)
Ventricular tachycardia or ventricular fibrillation 2 (4%)
Cardiac insufficiency 11 (19%)
Hypertension 23 (40%)
Diabetes 7 (12%)
Hyperlipidemia, medication prescribed 13 (23%)
Smoker/ex-smoker 18 / 11 (32/19%)
Data are given as absolute numbers (percentage) or as median and range.
CPR = cardiopulmonary resuscitation, BLS = basic life support, ACLS = advanced
cardiac life support, ROSC = restoration of spontaneous circulation, ICU =
intensive care unit, NSE = neuron specific enolase. Delay to rec overy of
consciousness has been counted from the withdrawal of sedative medication.
*Other aetiology of cardiac arrest: unknown for one subject, technical failure
of an implantable cardioverter defibrillator in one subject, and myocardial
sarcoidosis in one subject.
Table 2 Functional outcome of patients alive six months
after cardiac arrest (N = 57)
Lives at home 52 (91%)
Lives with family 46 (81%)
Lives alone 6 (11%)
Receives some help from family members 8 (15%)
Receives some help from social home-care system* 1 (2%)
Institutional care 5 (9%)
Sheltered home** 2 (4%)
Nursing home 1 (2%)
Long-term hospital 2 (4%)
Employed at the time of cardiac arrest 26 (46%)
Returned to previous employment 16 (61%)
On sick-leave, returned to work later on 3 (12%)
Retired from previous work due to the event 7 (27%)
Data are given as absolute numbers (percentage). *One alone-living patient
received help from a home-care nurse once a week with medication dispensing.
**These two patients had already lived in a sheltered home before
cardiac arrest.
Tiainen et al. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine (2015) 23:12 Page 4 of 7
Furthermore, the HRQoL of CA survivors did not differ
from that of age- and sex-matched normal population.
The proportion of independent patients in this study
was higher than the previously reported 65% one year
after CA from the pre-hypothermia era [24], and
comparable to that of hypothermia-treated patients re-
ported by Cronberg et al [25]. Focal neurological senso-
motor deficits among CA survivors are relatively
scarce, which was also reflected in the low NIHSS
scores among our study patients. The CPC outcome in
NIHSS ou tcome
0
5
10
15
20
25
30
35
40
45
50
NIHSS 0 NIHSS 1-4 NIHSS 5-10 NIHSS 10-12 NIHSS >12
stneitapforebmun
CPC outcome
0
5
10
15
20
25
30
35
40
CPC 1 CPC 2 CPC 3 CPC 4
s
t
n
ei
tapf
o
rebmuN
modifie d Rankin scale outc ome
0
5
10
15
20
25
30
35
mRs 0 mRs 1 mRs 2 mRs 3 mRs 4 mRs 5
stneit
a
pfor
e
b
m
un
Barthel Index outcome
0
10
20
30
40
50
60
BI 95-100 BI 55-90 BI 0-50
stneitapforebmun
Figure 2 CPC, Modified Rankin, Barthel Index and NIHSS six months after cardiac arrest. y-axis shows the percentage of patients.
0,6
0,65
0,7
0,75
0,8
0,85
0,9
0,95
1
Mobility
Vison
Hearing
Breathing
Sleeping
Eating
Speech
Elimination
Usual acti vitie s
Mentalfunction
Discomfort
Depression
Distress
Vitality
Sex ual a ctivity
Dimensions
Level val ue
Population
Patients
15D score
Population 0.904
Patients 0.883
* p=0.001, ** p=0.01
*
*
**
Figure 3 Self-assessed health-related quality of life by 15D in cardiac arrest survivors at six months compared to age- and gender
matched population.
Tiainen et al. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine (2015) 23:12 Page 5 of 7
our study was comparable to that of our Hypothermia
After Cardiac Arrest -study patients [26]. In resuscita-
tion studies it is usually assumed that all CA patients
have a pre-arrest CPC level of 1, which is not the case
in clinical settings. Thus, measuring change from as-
sumed pre-arrest CPC level in addition to the achieved
CPC level could reflect more accurately the clinical
outcome.
Recent large prospective multicenter study reported
that in medical and surgical ICU patients one out of four
patients had cognitive impairment 12 months after crit-
ical illness, similar in severity to that of patients with
mild Alzheimer’s disease; and that neurocognitive dys-
function occurred both in young and old patients [27].
Neuropsychological deficits are common in survivors of
CA, ranging from mild deficits in memory and executive
functions to severe amnestic syndrome. In the present
study half of studied survivors were cognitively intact at
six months after CA. As in previous studies with detailed
cognitive testing [9,25,28], the most frequent cognitive
deficits were found in memory and executive functions.
Extensive neuropsychological testing is not routinely of-
fered for all CA survivors, and studies concentrating on
predictors of cognitive outcome would be of great import-
ance in order to detect survivors needing further cognitive
evaluation and rehabilitation. Mild or moderate cognitive
impairments do not necessarily translate to deficits in the
activities in the daily living or threaten independency, but
especially in the current demanding work life even subtle
cognitive deficits may severely impair the person’sworking
capacity. Recognition of cognitive defects would thus be
important, as awareness of limitations enables the use of
compensating strategies. In our study 73% of survivors
employed at the time of CA returned to work. This high
percentage could be related to the relatively small number
of patients, but in previous studies this number has also
been quite high, between 42-79% [25,29-31].
In the study of Hsu et al, the CPC score at hospital
discharge correlated poorly with all categories of the
QoL measurements performed at least 6 months later
[32]. In our study the HRQoL score correlated well with
CPC and mRs assessed by a neurologist at six-months
after CA. Of note, for both CPC and mRs, there were
significant differences in HRQoL between outcome clas-
ses generally regarded as good outcome (CPC 1-2 and
mRs 0-2). It seems that even mild residual symptoms are
reflected as lower self-assessed QoL. On the other hand,
mild to moderate cognitive deficits did not result in sig-
nificantly lower self-assessed HRQoL. A possible explan-
ation for this is that 15D emphasizes physical symptoms,
compared to cognitive complaints. It is also possible that
patients with mild cognitive decline manage quite well in
familiar environment, adapt to their deficits, or alterna-
tively are unaware of their cognitive deficits. Further
studies examining the association of cognition and quality
of life using methods sensitive to symptoms caused by
cognitive deficits would be of importance.
Previous studies have suggested that most survivors of
out-of-hospital CA present a satisfactory quality of life
comparable to that of age- and disease-matched controls
[33-38]. In the study of Cronberg et al, CA survivors
had a slightly lower HRQoL measured by the EQ-5D
Visual Analogue Scale than an age-adjusted healthy co-
hort [25]. In our study the HRQoL of CA survivors did
not differ from that of age- and sex-matched control
population. In fact, their overall HRQoL measured by
the 15D single index score (median 0.883) was higher
than previously published scores for patients with coron-
ary artery disease six months after CABG (mean 0.858,
SD 0.110) or PCI (mean 0.847, SD 0.105) [21] and higher
than after stroke (median 0.86 [22], mean 0.801 [23]).
This study has some important limitations. First, 28% of
patients did not attend the neuropsychological examin-
ation. It is possible that subjects with cognitive deficits
were more prone to refuse the neuropsychological exam-
ination which may have caused bias. Second, we cannot
exclude the possibility that some of the noticed cognitive
deficits existed already before CA, although we tried to ex-
clude patients with pre-existing major cognitive impair-
ment. Third, due to the strict inclusion and exclusion
criteria, the results cannot be generalized to all OHCA
patients treated in the ICU with hypothermia. Finally, the
number of patients was inadequate to find any differences
between standard and intensive glucose control, if present.
Therefore, we analyzed the patients as one group.
Conclusions
In this study the functional outcome six months after
CA and therapeutic hypothermia was good (CPC1-2) in
88% of the survivors, and half of them were cognitively
intact. 95% of survivors had been able to return to their
home, and 73% of patients employed at the time of CA
had returned to work. Those who survived to six
months after CA had quality of life comparable to
age- and gender-matched population.
Competing interests
The authors declare that they have no competing interests.
Authors’contributions
MT, EP, TO, VP and TV obtained the data. MT, EP, TO and VP researched data.
MT and EP wrote the manuscript. MS, KMK and MC reviewed and edited the
manuscript. All authors read and approved the final manuscript.
Acknowledgements
The authors would like to thank professor Harri Sintonen, University of
Helsinki, for his help in analyzing 15D data. Marjaana Tiainen has received
support from the Maire Taponen foundation.
Author details
1
Department of Neurology, Helsinki University Hospital, Haartmaninkatu 4,
Helsinki 00029, Finland.
2
Institute of Behavioral Sciences, University of
Tiainen et al. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine (2015) 23:12 Page 6 of 7
Helsinki, Helsinki, Finland.
3
Intensive Care Units, Department of
Anaesthesiology and Intensive Care Medicine, Helsinki University Hospital,
Helsinki, Finland.
4
Karolinska Institutet, Institution of Clinical Science and
Education and Stockholm, Stockholm, Sweden.
5
Helsinki University and
HUCH Emergency Care, Helsinki University Hospital, Helsinki, Finland.
Received: 22 August 2014 Accepted: 30 December 2014
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