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RESEARCH ARTICLE
Patients with aneurysmal subarachnoid haemorrhage treated
in Swedish intensive care: A registry study
Arnlind Anna
1,2
| Danielsson Marita
2,3
| Engerström Lars
4,5
|
Tobieson Lovisa
1,2
| Orwelius Lotti
2,6
1
Department of Neurosurgery in Linköping, University Hospital, Linköping, Sweden
2
Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
3
The Swedish National Patient Insurance Company (Löf ), Stockholm, Sweden
4
Department of Anaesthesiology and Intensive Care, Vrinnevi Hospital, Norrköping, Sweden
5
Department of Thoracic and Vascular Surgery and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
6
Department of Anaesthesiology and Intensive Care, University Hospital, Linköping, Sweden
Correspondence
Arnlind Anna, Department of Neurosurgery,
University Hospital, 581 85 Linköping,
Sweden.
Email: anna.arnlind@regionostergotland.se
Abstract
Background: Aneurysmal subarachnoid haemorrhage (aSAH) is a life-threatening dis-
ease with high mortality and morbidity. Patients with aSAH in Sweden are cared for
at one of six neuro intensive care units (NICU) or at a general intensive care unit
(ICU).This study aimed to describe the incidence, length of stay, time in ventilator and
mortality for these patients.
Methods: This is a retrospective, descriptive study of patients with aSAH, registered
in the Swedish Intensive care Registry between 2017 and 2019. The cohort was
divided in sub-cohorts (NICU and general ICU) and regions. Mortality was analysed
with logistic regression.
Results: A total of 1520 patients with aSAH from five regions were included in the
study. Mean age of the patients were 60.6 years and 58% were female. Mortality
within 180 days of admission was 30% (n=456) of which 17% (n=258) died during
intensive care.
A majority of the patients were treated at one hospital and in one ICU (70%,
n=1062). More than half of the patients (59%, n=897) had their first intensive care
admission at a hospital with a NICU.
Patients in the North region had the lowest median GCS (10) and the highest SAPS3
score (60) when admitted to NICU. Treatment with invasive mechanical ventilation
differed significantly between regions; 91% (n=80) in the region with highest pro-
portion versus 56% (n=94) in the region with the lowest proportion, as did mortal-
ity; 16% (n=44) versus 8% (n=23). No differences between regions were found
regarding age, sex and length of stay.
Tobieson Lovisa and Orwelius Lotti are joint senior authors.
Received: 11 December 2023 Revised: 5 May 2024 Accepted: 6 May 2024
DOI: 10.1111/aas.14453
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium,
provided the original work is properly cited.
© 2024 The Authors. Acta Anaesthesiologica Scandinavica published by John Wiley & Sons Ltd on behalf of Acta Anaesthesiologica Scandinavica Foundation.
Acta Anaesthesiol Scand. 2024;68:1031–1040. wileyonlinelibrary.com/journal/aas 1031
Conclusions: Patients with aSAH treated in a NICU or in an ICU in Sweden differs in
characteristics. The study further showed some differences between regions which
might be reduced if there were national consensus and treatment guidelines
implemented.
KEYWORDS
intensive care, neuro intensive care, registry, subarachnoid haemorrhage, neurosurgery
Editorial Comment
In this retrospective study of 1520 patients with aneurysmal subarachnoid haemorrhage treated
in Swedish intensive care units, of whom 1125 underwent neurointensive care, these authors
report that disease severity on admission, duration of mechanical ventilation and intensive care
and outcome varied between healthcare regions. Large national datasets may help identify and
explore possible reasons for regional differences in treatment and outcome.
1|INTRODUCTION
Aneurysmal subarachnoid haemorrhage (aSAH) is a life-threatening
disease, associated with high mortality and morbidity and requires
neuro intensive care. Aneurysmal SAH affects relatively young indi-
viduals who are often in their most productive years with work and
family.
1,2
Patients with aSAH suffer a high risk of complications, with
re-bleeding from an unsecured aneurysm being a serious complication
and the leading preventable cause of death and disability after aSAH.
3
Other common complications due to the primary bleeding are vaso-
spasm and hydrocephalus, which can lead to an increased intracranial
pressure and ischaemia, with secondary brain injuries.
4,5
Aneurysmal
SAH is unique due to the risk of a delayed phase of these secondary
brain injuries caused by cerebral ischaemia.
6
Of the patients surviving
aSAH, around 30% have significant disabilities.
7,8
Common psycholog-
ical problems after aSAH are mood problems, difficulty concentrating
and problems with memory, impulsivity, anxiety, depression and
fatigue.
1,8
The general incidence of aSAH has decreased from 10.2 cases
per 100,000 persons in 1980 to 6.1 per 100,000 in 2010, but varies
between countries, and patients' sex, and age.
9
This might be due fas-
ter and more precise diagnosis, early aneurysm repair and advanced
neuro intensive care. Studies also describes reduced smoking and
hypertension as possible reasons for the reduced incidence.
9,10
Up to
26% of those affected by aSAH never arrive at intensive care because
they have died either directly when the bleeding occured,
11–13
or at
the emergency room at the hospital.
11
The management of aSAH patients is challenging
14
and they
should preferably be cared for by a multidisciplinary team in a specia-
lised Intensive Care Unit (ICU).
15
Patients cared for in intensive care in high volume centres have a
reduced mortality
16
but all patients with aSAH, even those who are
quickly transported to a hospital for treatment and care, are at high
risk of complications.
17
Over the past decades, the possibility of surviving aSAH has,
however, increased.
2,12,18
Some reasons might be improved diagnosis,
early aneurysm repair and advanced neuro intensive care.
2,6
Non-
traumatic SAH is the most common diagnosis at neuro intensive care
units (NICUs) in Sweden.
19
Sweden has roughly five ICU beds per 100,000 persons and out
of them are around 10% NICU-beds (0,5 NICU beds per 100,000 per-
sons).
20
Health care in Sweden is divided among 21 county councils,
which are tax funded. The county councils are clustered into six
healthcare regions with one NICU in each, from here on referred to as
regions. Patients with aSAH may initially be admitted to any of the
Intensive Care Units (ICUs) in Sweden, and a neurosurgeon is con-
sulted. If the neurosurgeon finds neurosurgical care appropriate for
the patient, the patient is transferred to the neurosurgical centre in
the region they belong to for treatment of the aneurysm with open
surgery or endovascular treatment (Figure 1). If the NICU in the region
has no available beds it's possible to transfer the patient to the ICU at
the same hospital since the hospital has full neurosurgical compe-
tence. However, it's becoming more common to care for patients with
aSAH in intermediate care units at the neurosurgery departments as
there are few neuro intensive care beds available. Although studies
show improved survival for patients with aSAH, there is still a need
for more research about treatment and management,
21
and national
consensus concerning treatment and care after the bleeding are lack-
ing. For an increased quality of the emergency care and the intensive
care period, healthcare needs to be more standardised and guidelines
developed,
22
which may improve knowledge and ensure ethical and
equal treatment and care. One way to gain more knowledge is to use
data from nationwide registers as those covers the whole population.
The Swedish Intensive Care Registry (SIR) was established 2001 and
reached full national coverage in 2020. There are no previous studies
on patients with aSAH with national data from SIR.
The primary aim of this study was to describe the incidence,
length of stay, time in ventilator and mortality for patients with aSAH
cared for at a NICU or an ICU.
The secondary aim was to compare this between Neuro Intensive
Care and Intensive Care, and in addition between the NICUs in differ-
ent healthcare regions in Sweden.
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2|METHODS
2.1 |Design and data source
This study is a retrospective, descriptive register study based on
national data from SIR covering 83 out of 84 intensive care units.
Data in SIR is validated locally and transferred to the registry for cen-
tral validation. At the registry, data are confirmed to be within pre
specified limits, and inconsistencies and illogical entries are identified.
If necessary, they are returned for correction before being added to
the database.
2.2 |Study setting and participants
Patients included in this study were admitted to Intensive Care
between 1 January 2017 to 31 December 2019 and diagnosed with
SAH (International Classification of Diseases, 10th revision [ICD-10]
codes I60.0-I60.7 and I60.9) and were 18 years and older. Patients
with a traumatic SAH and ICD-10 code I60.8 (Other non-traumatic
subarachnoid haemorrhage) were excluded to exclude patients with-
out documented source of bleeding.
2.3 |Variables
Variables used in this study were; age, sex, Glasgow Coma Scale
(GCS), Simplified Acute Physiology Score 3 (SAPS3), treatment with
an invasive mechanical ventilator (IMV), time on IMV, length of stay in
intensive care, and whether they were treated with neuro intensive
care or general intensive care. The outcome variables were ICU mor-
tality and mortality at 30 days and 180 days.
2.4 |Statistical analysis
Descriptive statistics were used to describe the characteristics of the
included patients and were summarised using mean (standard devia-
tion [SD]), median (interquartile range [IQR]) and frequency.
Logistic regression models were used to evaluate the association
between age, GCS (scale 3 to 15), SAPS3 score, time on IMV, treated
in NICU or general ICU and the outcomes; mortality at 30 days and
180 days. Cases with missing values were excluded.
All patients were first analysed as one group and then divided
into two groups; patients treated at a NICU or at a general ICU with
neuro intensive care at the same hospital, referred to as NICU, or
patients treated at a hospital with only general ICU, referred to as
ICU. The patients at an ICU at a hospital with NICU are included in
the NICU-cohort since they are in a hospital with full neurosurgical
competence such as neurosurgery and endovascular treatment. Para-
metric and when appropriate, non-parametric tests were used to com-
pare the two main subgroups; NICUs versus ICUs, and in addition the
NICU group was divided in five regions. Categorical variables were
compared using the Chi
2
-test.
To measure neurological status and a person's level of con-
sciousness both Glasgow Coma Scale (GCS) and Reaction Level
Scale (RLS-85) are used in Sweden. The data reported to SIR there-
fore includes both GCS and RLS-85, whereby the RLS-85 was trans-
lated to GCS.
23
Statistical analyses were performed with SPSS version 27 (IBM
Corporation, NY, USA), and SAS (version 9.4, ©Copyright I 2016 by
SAS Institute Inc., Cary, NC, USA).
FIGURE 1 Swedish healthcare regions, number of inhabitants in
the regions and locations of neuro intensive care units. aSAH,
aneurysmal subarachnoid haemorrhage; ICD, international
classification of diseases; ICU, intensive care unit; NICU, neuro
intensive care unit; SIR, Swedish Intensive Care Registry.
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This study was approved by the Swedish Ethical Review Author-
ity (Dnr 2020–04584), and the Swedish Intensive Care Registry
approved the extraction of the anonymised data. No patients can be
identified, and the results are presented on a group level.
3|RESULTS
A total of 1974 patients with aSAH were admitted to 59 different
ICUs during the study period. Patients <18 years (n=28), patients
without reported age (n=5) and patients with diagnosis ‘other SAH’
including perimesencephalic SAH (ICD-10 I60.8, n=91) were
excluded, resulting in 1850 patients with aneurysmal SAH. Since the
NICU in the Mid Sweden region was not affiliated to the registry and
did not report data during the study period, all other reported patients
from that region, admitted to general ICUs, were excluded (n=330).
Thus, a total of 1520 patients with aneurysmal SAH from the five
remaining regions were included in the study (Figure 2).
Due to the number of NICUs and their locations in Sweden,
patients might be cared for in more than one intensive care unit. A
majority of the patients were, however, treated at one hospital and in
one intensive care unit (70%, n=1062). Slightly more than half of the
patients (59%, n=897) had their first intensive care admission at a
hospital with a NICU (Figure 3).
The mean age for the patients was 60.6 years (±13.6) and 61% of
them (n=933) needed IMV during their intensive care stay.
The mortality within 180 days of admission was, 30% (n=456).
(Table 1).
3.1 |Neuro intensive care or intensive care
There were 1125 patients cared for at NICUs and 395 patients cared
for at general ICUs.
Patients in the ICU group were older than in the NICU group
(66.3 years ±14.1 vs. 58.7 years ±12.8). They also had worse neuro-
logical status at admission (median GCS =6 vs. 13), a higher median
SAPS3 score (63 vs. 51), their length of stay in intensive care were
shorter (23 h vs. 172 h) (Table 1).
Of patients treated in NICU, 21% (n=235) died within 180-days
of admission compared to the patients in the ICU 56% (n=221)
(Table 1).
FIGURE 2 Flow chart of patients
included in the study. aSAH, aneurysmal
subarachnoid haemorrhage; ICU,
intensive care unit; NICU, neuro Intensive
care unit; SIR, Swedish Intensive Care
Registry.
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3.2 |Predictors of mortality
In the regression model, cases with missing values were excluded,
meaning a total of 1430 patients were included in the model. All pre-
dictors, except GCS 9–12, were significantly associated with mortality
and for the age category 61–95 years the odds increased more than
twice (2.7) for 180-day mortality compared with the age category 18–
60 years (Table 2).
The need for IMV increased the odds for death compared to no
need for IMV. IMV for <48 h increased the OR 2.6, and for >48 h on
IMV the OR increased 3.0 for 180 day mortality compared to no need
for IMV (Table 2).
Patients cared for at a general ICU had a 4.0-fold increase in odds
for death within 180-days of admission compared to patient's cared
for at a NICU (Table 2).
3.3 |Neuro intensive care—Regions
There was no significant differences between the regions regarding
age, sex and length of stay, or concerning the mortality at 180 days
within the NICU-group. Concerning mortality during intensive care
there was, however, a significant difference, the largest proportion of
patients died in the South region and the lowest proportion died in
the West region (16% n=44 vs. 8% n =23) (Table 3).
Other significant differences concerned GCS and SAPS3, the
North region had the lowest median GCS (10) and the highest SAPS3
score (60) when admitted to NICU (Table 3).
There was also a significant difference between the regions
regarding the number of patients who were treated with IMV. The
North region had the largest proportion and the South-East region
the lowest (91% n=80 vs. 56% n=94). The time patients were trea-
ted with IMV ranged from less than 1 h to 1336.5 h and differed sig-
nificantly between regions, but the significant differences disappeared
when IMV time > 500 h were excluded (Table 3).
4|DISCUSSION
This study sought to describe the incidence, time in ventilator and
outcome in term of mortality for patients with aneurysmal SAH. The
result is also a description of similarities and differences between
patients treated in the NICU or in the ICU, and in addition
between regions in Sweden.
4.1 |The whole cohort
Of the patients registered in SIR with an aneurysmal SAH, 74% were
treated at a hospital with neurosurgical competence. This can be con-
sidered a low proportion, however, from available data it is not possi-
ble to determine whether this is a true reflection of practice or an
effect of non-aneurysmal SAB being registered as aneurysmal. A
majority (58%) of the patients were women and the mean age was
61 years. This is in line with other studies showing that patients suf-
fering from aSAH are predominantly women and have a mean age of
60 years.
24,25
With increasing age, peaking at 50–60, the incidence of aSAH
increases
26
and then remains stable until the age of 70 when it start
to decrease.
24
The overweight of women also contributes to more
women being admitted to NICU. More men than women are cared for
in a ICU and might depend on some of them having a non-aneurysmal
SAH, where some studies show that the incidence is higher for men
27
or the incidence is similar among men and women.
28
Some patients
might have been registered with the wrong ICD code. But it could also
depend on comorbidities and risk factors that we don't know from the
SIR data.
We found that there is a connection between the time on IMV
and mortality, but it may be linked to how badly injured the patient
was when admitted and not caused by primary or secondary compli-
cations from mechanical ventilation. Although longer ventilator time is
linked to more complications. The 30-day mortality in our study was
25% and is consistent with other studies.
24,29,30
Mortality is a crude outcome for patients with aSAH and says
nothing about the health-related quality of life (HRQoL) for the
FIGURE 3 Sankey diagram showing the flow of the patients
included in the study between intensive care units. ICU, intensive care
unit; NICU, neuro intensive care unit.
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TABLE 1 Description of patients with aSAH treated in Swedish intensive care during 2017–2019. The whole cohort and divided in two
groups; one treated in NICU and the other in general ICU.
Patient's characteristics
The whole cohort
(n=1520) NICU n=1125 ICU n=395
p(Between NICU
& ICU)
Age, mean (±SD), years 60.6 (±13.6) 58.7 (±12.8) 66.3 (±14.1) <.001
Sex, n (%) <.001
Female 875 (57.6) 682 (60.6) 193 (48.9)
GCS, median (IQR)
a,b
13.0 (5.0, 15.0) 13.0 (8.0, 15.0) 6.0 (3.0, 13.0) <.001
GCS groups
a,b
3–8 566 (37.2) 333 (39.6) 233 (59.0)
9–12 167 (11.0) 130 (11.6) 37 (9.4)
13–15 748 (49.2) 630 (56.0) 118 (29.9) <.001
Total SAPS3, median (IQR) ₁54.0 (44.0, 67.0) 51.0 (44.0, 63.0) 63.0 (50.0, 77.0) <.001
Ventilator treatment IMV, n (%) 933 (61.4) 709 (63.0) 224 (56.7) .027
Time on IMV, median hours (IQR) 52.0 (19.5, 228.8) 79.0 (23.4, 285.2) 29.6 (11.2, 59.2) <.001
Total length of stay intensive care, median hours
(IQR)
109.7 (30.5, 279.9) 171.5 (62.6, 356.1) 23.3 (6.1, 53.8) <.001
ICU-mortality, n(%)
b
258 (17.0) 144 (12.8) 114 (28.9) <.001
30-day mortality, n(%)
b
386 (25.4) 182 (16.2) 204 (51.6) <.001
180-day mortality, n(%)
b
456 (30.0) 235 (20.9) 221 (55.9) <.001
Note:p< .05 was statistically significant.
Abbreviations: aSAH, aneurysmal subarachnoid haemorrhage; GCS, Glasgow Coma Scale; ICU, intensive care unit; IMV, invasive mechanical ventilation;
IQR, Inter quartile range; NICU, neuro intensive care unit; SAPS3, Simplified Acute Physiology Score 3; SD, standard deviation.
a
First admission.
b
Missing values: GCS n=39, mortality ICU =41, mortality30/180 =52.
TABLE 2 Association between
predictors and 30/180 day mortality
among 1430 admissions in multivariable
logistic regression.
30 day-mortality 180 day-mortality
OR (95% CI) pOR (95% CI) p
Age, years
18–60 Reference Reference
61–95 1.76 (1.24–2.49) .001 2.74 (1.95–3.79) <.0001
Time on ventilator
0 h (no ventilator) Reference Reference
0,1–48 h 3.77 (2.24–6.35) <.0001 2.60 (1.64–4.15) <.0001
>48 h 2.82 (1.62–4.92) .0003 2.96 (1.81–4.83) <.0001
Neuro intensive care
Yes Reference Reference
No 4.54 (3.04–6.77) <.0001 3.94 (2.70–5.75) <.0001
Glasgow Coma Scale admission
GCS 13–15 Reference Reference
GCS 9–12 1.20 (0.64–2.25) .571 1.17 (0.69–1.98) .557
GCS 3–8 5.92 (3.60–9.72) <.0001 4.14 (2.67–6.43) <.0001
Simplified Acute Physiology Score 3
SAPS3 0–60 Reference Reference
SAPS3 61–80 3.04 (2.04–4.54) <.0001 2.98 (2.07–4.30) <.0001
SAPS3 81–125 8.78 (4.36–17.66) <.0001 9.58 (4.50–20.40) <.0001
Note: 1430 patients included in the regression due to missing data in one or more variables.
Abbreviations: CI, confidence interval; OR, odds Ratio; Ventilator, invasive mechanical ventilation.
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TABLE 3 Description of patients with aSAH treated in Swedish neuro intensive care during 2017–2019. The NICU cohort and healthcare regions.
Patient's characteristics
The NICU cohort
(n=1125)
North healthcare
region (n=88)
Stockholm/Gotland
healthcare region (n=294)
South East healthcare
region (n=169)
South healthcare
region (n=276)
West healthcare
region (n=298)
p(between
regions)
Age, mean (±SD), years 58.7 (±12.8) 61.7 (±11.5) 57.4 (±13.2) 59.1 (±13.4) 59.4 (±12.5) 58.1 (±12.7) .046
Sex, n(%) Female 682 (60.6) 57 (64.8) 177 (60.2) 101 (69.8) 170 (61.6) 177 (59.4) .909
GCS, median (IQR)
a,b
13.0 (8.0, 15.0) 10.0 (6.0, 13.0) 14.0 (7.0, 15.0) 13.0 (10.0, 15.0) 13.0 (8.0, 15.0) 14.0 (8.0, 15.0) <.001
GCS groups
a,b
3–8 333 (30) 39 (44.3) 81 (27.6) 37 (21.9) 98 (35.5) 78 (26.2)
9–12 130 (12) 17 (19.3) 35 (11.9) 18 (10.7) 28 (10.1) 32 (10.7)
13–15 630 (58) 23 (26.1) 177 (60.2) 107 (63.3) 149 (54.0) 174 (58.4) <.001
Total SAPS3, median (IQR)
a
51.0 (44.0, 63.0) 60.0 (48.5, 68.0) 53.0 (44.0, 67.0) 52.0 (45.0, 62.0) 48.0 (30.0, 59.0) 50.0 (44.0, 62.0) <.001
Ventilator treatment IMV, n(%) 709 (63.0) 80 (90.9) 198 (67.3) 94 (55.6) 159 (57.6) 178 (59.7) <.001
Time on IMV, median hours
(IQR)
79.0 (23.3, 286.3) 133.7 (43.1, 366.7) 87.5 (18.7, 290.1) 127.0 (22.3, 325.2) 61.1 (24.8, 212.5) 63.2 (21.0–279.6) .023
Total lenght of stay intensive
care, median hours (IQR)
171.5 (62.5, 356.1) 168.6 (58.6, 390.7) 177 (89.2, 351.5) 194.0 (65.1, 358.5) 146.6 (43.5, 362.5) 165.4 (59.1, 337.6) .245
ICU-mortality, n(%)
b
144 (12.8) 13 (14.8) 44 (15.0) 20 (11.8) 44 (15.9) 23 (7.7) .018
30-day mortality, n(%)
b
182 (16.2) 17 (19.3) 45 (15.3) 24 (14.2) 58 (21.0) 38 (12.5) .052
180-day mortality, n(%)
b
235 (20.9) 24 (27.3) 58 (19.7) 34 (20.1) 67 (24.3) 52 (17.4) .135
Note:p< .05 was statistically significant.
Abbreviations: aSAH, aneurysmal subarachnoid haemorrhage; GCS, Glasgow Coma Scale; IMV, invasive mechanical ventilation; IQR, inter quartile range; NICU, neuro intensive care unit; SAPS3, Simplified Acute
Physiology Score 3; SD, standard deviation.
a
First admission.
b
Missing values.
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survivors. It is possible to register RAND-36 in SIR but the coverage
for that variable is very low. The patients' functional outcome and
HRQoL could be assessed using general instruments such as EQ-
5D,
31
or RAND-36
32
with complement of for example a disease spe-
cific instrument for disability after stroke (Modified Rankin Scale
33
), or
disability and recovery after traumatic brain injury, (Glasgow Outcome
Scale Extended
34
).
5|NICU/ICU
Patients admitted to NICUs were younger than patients admitted to
general ICUs, which is consistent with earlier research.
24
Since the
available NICU-beds in Sweden are around 0.5 beds per 100,000
individuals,
20
priorities have to be made before admitting patients to
the NICU and different factors have to be considered. These are, for
example, comorbidities, the estimated survival and ability to endure a
long rehabilitation process; these factors may be associated with age.
However, there are no written consensus or guidelines as to how pri-
orities should be decided. The factors mentioned are important, but
there is also always an individual component to consider.
The 30-day mortality in the NICU group was 16% compared to
52% in the ICU group. The mortality rate for the NICU group is con-
sistent with earlier studies.
13
The patients in the subgroups (NICU and ICU) differ in patient
characteristics and the care given at NICU or ICU is different, to the
extent that those who are not taken to NICU are not offered secure-
ment of the aneurysm or neuro intensive care. Our data shows differ-
ences in outcome, but it cannot be concluded whether this is caused
by differences in care. The conclusions that can be drawn from the
study is that there is a selection of patients that are accepted to NICU.
A difference in mortality is therefor to be expected. Table 1shows
that 118 patients with GCS 13–15 were cared for at an ICU. Although
we cannot verify this, it is plausible that some patients with SAH
might have been registered with the wrong ICD code for example
patients with classic symptoms, blood in the subarachnoid space but
no source of bleeding is found. We have tried to avoid this by exclud-
ing patients with only ICD code I60.8, but some errors may still be in
the register.
Both time on IMV and length of stay in intensive care were longer
for the NICU group compared with the ICU group. The ICU group
were in worse condition when admitted, with a higher SAPS3 score
and lower GCS. An explanation is probably that patients in ICUs die or
are extubated earlier due to their more severe condition, and the dif-
ferences in mortality support this explanation. Decisions for palliative
treatment are probably taken earlier for the ICU group and patients
with a better prognosis are accepted for transfer to NICU.
After adjusting for age, neurological status at admission, SAPS3
score and time on IMV, both 30- and 180-day mortality was reduced
for patients in the NICU group compared with those in the ICU group.
This is in line with earlier studies, which have shown that it is prefera-
ble for the majority of patients to be cared for at hospitals with neuro-
surgical competence. Studies from other countries have shown a
lower mortality rate for patients treated in hospitals with high volume
of SAH cases compared to low-volume hospitals.
16
As acceptance to
NICU depends on other prognostic factors such as comorbidities, esti-
mated survival even without the severity of SAH, and technical treat-
ment options and the neurological status of the patients, we cannot
rule out that this is caused by residual confounders.
5.1 |Regions
Our results showed that there are differences between the regions
concerning the use (or not) of IMV. If the patient is intubated or not,
is probably affected by transport time and the geographical challenges
concerning the distance to NICUs in Sweden (Figure 1). Another
explanation to differences concerning time on IMV is the effect of
outliers, as the significant differences disappeared when IMV
time > 500 h were excluded.
In our study there was a difference between regions concerning
the number of patients taken to NICU or not and mortality in inten-
sive care. There were also differences concerning GCS and SAPS3 at
admission. There seem to be different routines for these patients
among different regions. Reasons for admitting the patients to NICU
or not, apart from the patient's medical condition, could be the area of
the region, including the distances and different possibilities for trans-
port, the organisation of intensive care and/or intermediate care in
the region and available beds. Studies have shown conflicting results
regarding association between delayed admission and mortality,
35,36
but that the time from the initial bleeding to the admission at a NICU
is a risk factor for re-bleeding.
36
Another explanation for these differences could be the lack of
consensus in Sweden of how to treat and care for patients with
aSAH, as decisions are made regionally at the NICUs. It is important
with national consensus for efficient utilisation of existing resources
and health care at equal terms. Although existing evidence is not
apparent information from the registry can help to find the best
practice.
5.2 |Study strengths and limitations
A strength of this study is that the data are on a national level with
the vast majority of patients with aSAH cared for in Intensive Care
included. Our data from SIR covers 70% of the patients dying from a
SAH.
37
The other 30% dying from a SAH could be patients dying at
ictus or patients treated in intermediate care, and therefore not regis-
tered in the intensive care register.
One limitation of the study is the missing data from one region
which did not report to the register at the time of the study. It is pos-
sible to register RAND-36 to SIR but it is only reported for approxi-
mately 5% of the patients in this study whereby mortality was used as
the only outcome variable. More nuances to this complex issue and
information about functional outcome and a patient reported out-
come measure (PROM) would have been desirable.
1038 ANNA ET AL.
13996576, 2024, 8, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/aas.14453 by Linkoping Universitet, Wiley Online Library on [15/11/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License
There is always a risk of misclassification and bias with data from
large national registers in which data are collected by several
individuals.
There is only a coarse description of comorbidity included in
SAPS3. We believe that not only neurological status, age, gender and
SAPS3 differ, but also comorbidity.
6|CONCLUSIONS
This study shows characteristics for patients with aSAH treated in
intensive care in Sweden. The majority of these patients are treated
at NICU, and patients not transferred to NICU are a heavily selected
group, thus differences in mortality between these groups is to be
expected. Overall mortality in Sweden was in line with previous
research, however, the authors stress the need for more research
concerning the health-related quality of life for the surviving
patients. There were some differences between regions in terms of
the proportion of patients taken to NICU or not and mortality in
intensive care. Such differences might be reduced if there were
national consensus or guidelines implemented for this patient
group.
AUTHOR CONTRIBUTIONS
Conceptualisation and methodology: AA, MD, LO and LT; Data analysis:
AA, LE and LO. Formal analysis: AA, MD, LE, LO and LT. Writing—
original draft: AA, MD, LE, LO and LT. All authors provided critical revi-
sion of the article and have read and provided final approval of the
version submitted for publication.
ACKNOWLEDGEMENTS
We acknowledge all participating ICUs in the Swedish Intensive Care
Registry for their participation and hard work to contribute data.
FUNDING INFORMATION
The work was supported by institutional funds for doctoral studies.
CONFLICT OF INTEREST STATEMENT
All authors declare no conflicts of interest.
DATA AVAILABILITY STATEMENT
The data that support the results of this study might be available on
reasonable request if the Swedish Intensive Care Registry approves.
ORCID
Arnlind Anna https://orcid.org/0000-0003-2514-1902
Engerström Lars https://orcid.org/0000-0003-4920-5392
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How to cite this article: Anna A, Marita D, Lars E, Lovisa T,
Lotti O. Patients with aneurysmal subarachnoid haemorrhage
treated in Swedish intensive care: A registry study. Acta
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