Thoracic trauma severity contributes to differences in intensive care therapy and mortality of severely injured patients: analysis based on the TraumaRegister DGU®
Bayer et al. World Journal of Emergency Surgery
Thoracic trauma severity contributes to differences in intensive care therapy and mortality of severely injured patients: analysis based on the TraumaRegister DGU®
Jörg Bayer 0 3
Rolf Lefering 2
Sylvia Reinhardt 1
Jan Kühle 0 3
Jörn Zwingmann 0 3
Norbert P. Südkamp 0 3
Thorsten Hammer 0 3
TraumaRegister DGU 4
0 Department of Orthopedics and Trauma Surgery, Medical Center - Albert-Ludwigs-University of Freiburg, Faculty of Medicine, Albert-Ludwigs-University of Freiburg , Hugstetter Str. 55, 79106 Freiburg , Germany
1 Department of Orthopedics and Trauma Surgery , Oberschwabenklinik St. Elisabeth, Elisabethenstr. 15, 88212 Ravensburg , Germany
2 FOM - Institute for Research in Operative Medicine, University Witten/Herdecke, Faculty of Health , Ostmerheimer Str. 200, 51109 Köln , Germany
3 Department of Orthopedics and Trauma Surgery, Medical Center - Albert-Ludwigs-University of Freiburg, Faculty of Medicine, Albert-Ludwigs-University of Freiburg , Hugstetter Str. 55, 79106 Freiburg , Germany
4 Committee on Emergency Medicine, Intensive Care and Trauma Management of the German Trauma Society (Sektion NIS) , Berlin , Germany
Background: Thoracic trauma is a relevant source of comorbidity throughout multiply-injured patient care. We aim to determine a measurable influence of chest trauma's severity on early resuscitation, intensive care therapy, and mortality in severely injured patients. Methods: Patients documented between 2002 and 2012 in the TraumaRegister DGU®, aged ≥ 16 years, injury severity score (ISS) ≥ 16 are analyzed. Isolated brain injury and severe head injury led to exclusion. Subgroups are formed using the Abbreviated Injury ScaleThorax. Results: Twenty-two thousand five hundred sixty-five patients were predominantly male (74%) with mean age of 45. 7 years (SD 19.3), blunt trauma (95%), mean ISS 25.6 (SD 9.6). Overall mean intubation period was 5.6 days (SD 10.7). Surviving patients were discharged from the ICU after a mean of about 5 days following extubation. Thoracic trauma severity (AISThorax ≥ 4) and fractures to the thoracic cage significantly prolonged the ventilation period. Additionally, fractures extended the ICU stay significantly. Suffering from more than one thoracic injury was associated with a mean of 1-2 days longer intubation period and longer ICU stay. Highest rates of sepsis, respiratory, and multiple organ failure occurred in patients with critical compared to lesser thoracic trauma severity. Conclusion: Thoracic trauma severity in multiply-injured patients has a measurable impact on rates of respiratory and multiple organ failure, sepsis, mortality, time of mechanical ventilation, and ICU stay.
Severely injured; Polytrauma; Thoracic trauma; Chest injury; Organ failure; Mortality
Chest trauma ranks as the most important injury in
severely injured patients, and about 50% of those with
multiple trauma suffer from an associated chest injury
]. Injury to the thorax may affect the thoracic wall
(e.g., rib, sternum fracture) as well as thoracic organs
(e.g., lung, heart, vessels) to a different extent. Only a
minority of patients with thoracic trauma tends to
develop respiratory failure requiring intubation and
ventilator support to correct hypoxia and hypercapnia
. On the other hand, 35 to 58% of severely injured
patients require prehospital intubation, depending on
the severity of concomitant chest injury [
severely injured patients usually require intensive care
therapy irrespective of accompanying thoracic injuries,
organ dysfunction and multiple organ failure (MOF) are
known to develop more often in patients with severe
thoracic trauma . In severely injured patients, including
those with severe traumatic brain injury (TBI), at least one
organ failed in about 52%, with lung failure occurring in
]. Overall, MOF rates of 13 to 33% have been
reported in severely injured patients. While lung failure
rates ranged from 50 to 65% in MOF patients [
7% of patients without MOF suffered from lung failure .
Overall, MOF patients require prolonged ventilation and
remain longer in the intensive care unit (ICU), thus
consuming considerable health care resources [
Severe multiple trauma is often associated with
traumatic lung injury and presents with a wide spectrum of
]; the reported mortality of chest trauma can be
as high as 60% [
], and 20 to 25% of deaths in severely
injured patients are attributed to chest injury [
Taking care of a severely injured patient is demanding.
Differences in prehospital and early clinical trauma
management have been reported that depends on the severity
of an accompanying chest trauma [
patients with blunt chest trauma require significantly
longer periods of mechanical ventilation and a significantly
longer stay in the ICU than trauma patients without a
thoracic injury [
]. Furthermore, chest injuries predispose
to pneumonia [
], adult respiratory distress syndrome
], and multiple organ dysfunction syndrome
]. Therefore, we aimed to determine whether
the chest trauma’s severity in severely injured patients
reveals a measurable influence on early resuscitation,
intensive care therapy, and mortality.
The TraumaRegister DGU®
The TraumaRegister DGU® (TR-DGU) of the German
Trauma Society (Deutsche Gesellschaft für Unfallchirurgie,
DGU) was founded in 1993. The aim of this multicenter
database is the anonymized and standardized
documentation of severely injured patients’ care.
Data are collected prospectively in four consecutive
time periods from the accident site until hospital
discharge: (A) pre-hospital phase, (B) emergency room
and initial surgery, (C) ICU, and (D) discharge.
Documentation includes detailed information on demographics,
injury pattern, comorbidities, pre- and in-hospital
management, course in the ICU, relevant laboratory findings
including each individual’s data on transfusions, and
outcome. The inclusion criterion is admission to the hospital
via the emergency room with subsequent ICU/ICM care
or reaching the hospital with vital signs and dying before
admission to the ICU.
The infrastructure for documentation, data
management, and data analysis is provided by AUC—Academy
for Trauma Surgery (AUC—Akademie der Unfallchirurgie
GmbH), a company affiliated with the German Trauma
Society. Scientific leadership is provided by the Committee
on Emergency Medicine, Intensive Care and Trauma
Management (Sektion NIS) of the German Trauma
Society. The participating hospitals submit their
anonymized data into a central database via a web-based
application. The quality of the scientific data analysis is
monitored by peer review procedure established by
The participating hospitals are primarily located in
Germany (90%), but a rising number of hospitals in other
countries are contributing data as well (at the moment
from Austria, Belgium, China, Finland, Luxemburg,
Slovenia, Switzerland, The Netherlands, and the United
Arab Emirates). Currently, approximately 35,000 cases
from more than 600 hospitals have been entered into the
database per year.
Participation in TR-DGU is voluntary. For hospitals
associated with TraumaNetzwerk DGU®, however, the
entry of at least a basic data set is obligatory for reasons
of quality assurance. Hospitals interested in trauma
research must enter a standard data collection form that
contains more comprehensive information (e.g., organ
failure, sepsis) on the patient course compared with the
basic data set.
Patients documented between 2002 and 2012 in the
TR-DGU were analyzed for eligibility in this
investigation. Patient selection was carried out based upon the
(1) online documentation from European trauma
centers, (2) age ≥ 16 years, (3) ISS ≥ 16, (4) exclusion of
isolated brain injuries, and (5) exclusion of severe head
injury defined as AISHead ≥ 4 to prevent confounding,
since severe head trauma may pose an indication for
intubation itself [
Injuries were graded according to the 2005 version of
the Abbreviated Injury Scale (AIS) [
], and the injury
severity score (ISS) was calculated as described [
While the ISS is calculated from the three worst affected
body regions as the sum of squares of the respective AIS
severity levels, the New ISS (NISS) is calculated in a
similar way, but instead of their location, the three worst
injuries enter the equation [
Length of mechanical ventilation in ICU was defined as
the number of days spent in the ICU with endotracheal
intubation or a tracheostomy and mandatory mechanical
ventilation (excluding, e.g., non-invasive ventilation).
Length of hospital stay was defined as the time spent in
primary care in the hospital participating in the TR-DGU.
Organ failure was assessed by the SOFA score as
described previously. The SOFA score describes organ
function in the respiratory, cardiovascular, renal,
hematologic, hepatic, and central nervous systems [
Each organ system was graded to evaluate the severity of
organ dysfunction or failure. Patients with organ failure
entered in the TR-DGU database had to have met the
SOFA score criteria for organ failure for at least 2 days.
Multiple organ failure (MOF) and sepsis were assessed
according to published guidelines [
]. Sepsis was
defined as a systemic response to infection (presence of
microorganisms). Data on respiratory failure, MOF, and
sepsis were available on patients documented via the
standard data collection form only.
Patient subgroups were defined according to the chest
injury severity (AISThorax). The first group consisted of
patients with no relevant thoracic injuries (AISThorax = 0
or 1), serving as a control group (“controls”). Group
AIS-2 consisted of patients with AISThorax = 2. Group
AIS-3 consisted of patients with AISThorax = 3. Group
AIS-4 consisted of patients with AISThorax = 4. Group
AIS-5/6 consisted of patients with AISThorax = 5 and 6,
comprising the highest severity of chest trauma.
AISThorax included all thoracic injuries coded as
AIS = 4xxxxx.x [
]. Injuries to the thoracic spine were
excluded, as these were coded with an AIS = 6xxxxx.x
Demographic and clinical characteristics comparing the
aforementioned groups were evaluated using descriptive
statistics. Continuous variables are presented as mean
with standard deviation (SD), while categorical variables
are presented as number of cases with percentages. The
respective statistics refer to patients with valid data sets
only. Therefore, the total number of patients or
characteristics may sometimes vary.
Data for respiratory failure (ARDS), sepsis, and MOF
are not part of the basic data set; therefore, not all
hospitals provide this information, and patient numbers vary.
Formal statistical testing would require an initial overall
test (chi-squared, analysis of variance, or
KolmogoroffSmirnov) followed by pair-wise comparisons in case of
significance. With five subgroups, the number of pair-wise
tests would be ten per variable. Since the number of
patients in the five subgroups ranged from 2000 to 8000,
even minor differences would reach statistical significance.
The 95% confidence interval in groups of 2000 cases (or
more) would be about +/− 2% (or less) in case of
categorical variables, and +/− 0.025*SD in case of continuous
variables. For these reasons, we refrained from formal
statistical testing, and our analysis is mainly descriptive.
Statistical testing for influencing factors on length of
ICU stay and mechanical ventilation was performed
using multiple linear regression analysis. In this analysis,
the dependent variables were length of ICU stay and
length of mechanical ventilation, respectively. The
independent variables consisted of patient characteristics
(age ≥ 60 years, gender, concomitant diseases), injury
severity (ISS, AISThorax ≥ 4, AISHead = 3, AISAbdomen ≥ 3,
AISExtremity ≥ 3), therapeutic interventions (ICU
admission intubated/ventilated, blood transfusion), and type of
injury to thoracic structures (vascular, lung, bone). Only
surviving patients were included in this statistics. A p
value of < .05 was considered significant.
All data were analyzed using SPSS, version 22.0 (IBM
Inc., Armonk, NY, USA).
To analyze changes over time, we divided our 10-year
data set into subgroups of 2 consecutive years each.
The present study is in line with the publication
guidelines of the TraumaRegister DGU® and registered as
TR-DGU project ID 2011–015.
Our study cohort has been described, analyzed for
different characteristics, and published before [
Data of 37,495 severely injured patients, including
patients with head injuries of any severity, with an
ISS ≥ 16 and aged ≥ 16 years were entered into the
database. Of these, 64.3% suffered from at least moderate
(AISThorax ≥ 2) and 26.7% from severe thoracic injury
(AISThorax ≥ 4), respectively.
After excluding patients suffering from severe head
injury (AISHead ≥ 4), a total of 22,565 severely injured
patients aged a mean 45.7 years (SD 19.3) and presented
a mean ISS of 25.6 (SD 9.6) were identified for further
The standard data collection form (including data for
respiratory failure, MOF, and sepsis) was filed for 16,793
(74.4%) patients, yet ~ 13% of these datasets were
incomplete and excluded for analysis of the respective
The study group’s basic characteristics are summarized
in Table 1. The patients suffering mainly from blunt
trauma included in our study are predominantly male.
The distribution of injuries to different thoracic
structures is dependent on thoracic trauma severity and is
shown in Table 2. Most patients suffer from injuries to
the lung, whereas injury to intrathoracic vessels is less
prevalent in patients suffering from thoracic trauma
(AISThorax ≥ 2).
After primary work up in the emergency department,
the rate of patients transferred directly to the
Intensive Care Unit (ICU) was higher for AISThorax ≥ 3
(42.3– 47.8%) than AISThorax ≤ 2 (37.1–30.8%). The
remaining patients underwent, for example, early (e.g.,
external fracture stabilization) or emergency (e.g.,
The higher their AISThorax score, the more patients
who were admitted to the ICU were intubated and
Table 1 Basic characteristics: groups according to the AISThorax (0 + 1, 2, 3, 4, and 5 + 6)
Controls AIS-2 AIS-3
n = 4870 n = 1973 n = 8052
Age (years) Mean ± SD 44.2 ± 19.6 41.7 ± 18.6 45.3 ± 19.2
ISS Mean ± SD
New ISS Mean ± SD
mechanically ventilated. Additionally, a one-point increase
in the AISThorax resulted in about a 1-day longer
intubation period in ICU. Overall, we report a mean intubation
period of 5.6 days (SD 10.7) in all our severely injured
patients. Again, length of the ICU stay increased with the
AISThorax score and was a mean of 10.1 days (SD 13.4) in
our overall population (Table 3).
In the subgroup of surviving patients only, the higher
their AISThorax score was, the longer the intubation
period and ICU stay were. The mean duration of
intubation was 5.6 days (SD 10.4) and mean length of ICU
stay was 10.6 days (SD 13.2) for all groups presenting
different thoracic trauma severity. Within each group,
patients stayed in the ICU for a mean of approximately
5 days after extubation (Fig. 1).
In our multiple linear regression analysis for
influencing factors (patient characteristics, injury severity,
therapeutic interventions, and type of injury to thoracic
structures) on ICU length of stay and length of
mechanical ventilation, we found no effect for higher thoracic
trauma severity (AISThorax ≥ 4) on ICU length of stay
(+ 0.2 days; p = 0.54) but a significant effect on
intubation days (+ 0.7 days; p = 0.005).
While vascular and lung injury did not significantly
affect ICU length of stay and ventilation days, fractures
significantly prolonged ICU length of stay (+ 1.7 days;
p < 0.001) and intubation days (+ 0.9 days; p < 0.001).
We detected an influence from having one versus several
diagnosed thoracic injuries on the duration of both
mechanical ventilation and length of ICU stay, namely a one- to
two-day mean increase in the duration of mechanical
ventilation and ICU stay in patients suffering from multiple
Groups according to the AISThorax (2, 3, 4, and 5 + 6) and all patients
with AISThorax ≥ 2
Number of patients (with AISThorax ≥ 2) and percentages are given for
“vascular” (intrathoracic vascular injury), “lung” (e.g., lung contusion, laceration,
pneumothorax) and “bone” (rib and sternal fractures) injuries
thoracic injuries. This was seen within each group of
thoracic trauma severity (AISThorax) ≥ 3. Again,
irrespective of the counted thoracic injuries, patients
remained about 5 days longer in the ICU than being
mechanically ventilated (Table 4).
In patients scoring an AISThorax ≥ 2, one thoracic
injury meant a mean 5.2 days of mechanical ventilation
and 9.5 days of ICU stay versus 6.9 and 11.8 days with
multiple thoracic injuries, respectively.
Length of hospital stay
The length of hospital stay of all our severely injured
patients decreased from a mean of 28.1 days (SD 27.2) in
the controls with an AISThorax ≤ 1 to 23.4 days (SD 24.2)
for those with AIS-5/6 (Table 3). When considering the
surviving patients only, we identified no differences in
length of hospital stay in conjunction with varying chest
trauma severities (Fig. 2). Overall, the surviving patients,
irrespective of their chest trauma severity, were
hospitalized a mean of 28.8 days (SD 24.9).
While multiple chest trauma diagnoses in our severely
injured patients—compared to a single diagnosis—were
not associated with longer hospital stays for AISThorax ≤ 4,
patients with an AISThorax ≥ 5 suffering from multiple
chest trauma had an approximately 3.5 days longer mean
hospital stay than patients presenting a single thoracic
trauma diagnosis (20.9 versus 24.2 days).
Our severely injured patients revealed a higher rate of
lung failure (defined as a Horowitz index ≤ 200 mmHg
for at least 2 days (SOFA-Score [
]) the higher their
AISThorax was. While 13.9% of the patients with an
AISThorax ≤ 1 suffered from acute lung failure, 40.3% of
those with an AISThorax ≥ 5 did.
Rates of sepsis, respiratory failure, and MOF were
higher in patients with greater thoracic trauma severity.
The AIS-5/6 group displayed more than twice the rate
of MOF, respiratory failure, and sepsis than the control
subgroup (Table 5).
Early death within 24 h after admission to the hospital
occurred in 6.7% of all our severely injured patients, and
a total of 10.6% died during their hospital stay. When
Number of patients and percentages requiring mechanical ventilation during their ICU stay. Length of mechanical ventilation, ICU stay, and hospital stay in days
(mean ± SD); [median]. Subgroups according to the AISThorax (0 + 1, 2, 3, 4, and 5 + 6)
examining the distribution of chest trauma severity in our
deceased patients, we found higher mortality in those with
an AISThorax ≥ 4 (this applies to the early deaths as well as
all deaths during hospital stay) (Table 5).
Death usually occurred while the patients were in the
ICU. Late mortality, meaning death occurring later than
3 days after ICU discharge, occurred more often in
patients with an AISThorax ≤ 3 (about 10% of patients in
each group). An AISThorax = 4 was associated with 5.2%,
an AISThorax ≥ 5 with 3% of the late deaths.
Patients sustaining multiple chest injuries within one
AISThorax severity score did not reveal mortality rates
different from those of patients with one thoracic
Changes over time
The rate of severely injured patients being admitted
intubated to the ICU dropped steadily over the decade we
examined. While 83% of patients arrived in the ICU on
mechanical ventilation between 2002 and 2003, only 59.3%
were intubated between 2010 and 2012. We noted the same
pattern in all groups during those years when patients are
segregated according to their chest trauma severity (Fig. 3).
While the rate of acute lung failure in all groups
(including the subgroups with varying chest trauma
severity (data not shown)) revealed no distinct trend
over the decade, mortality during hospital stay did fall
from 13.5 to 10.1% for all patients from 2002 to
2012. Mortality in all groups is now lower than it was
in 2002 (Fig. 4).
We present a retrospective analysis of severely injured
patients suffering from thoracic traumas of different
magnitude. As in other studies [
6, 13, 19–22
population consists mainly of middle-aged males with a mean
ISS ≥ 16 suffering from blunt trauma. Severe head
trauma (AISHead ≥ 4) alone can be an indication for
intubation , and concomitant head and thoracic
trauma influence each other in terms of intensive care
]. Previous studies have shown that
severely injured patients with head and chest injuries
require prolonged intensive care stay and mechanical
ventilation , and thoracic injury is known to be an
independent risk factor for 30-day mortality and poor
outcome in patients suffering traumatic brain injuries
]. Thus, by excluding patients with severe head
trauma (AISHead ≥ 4), we minimized the risk of
confounding our target parameters by such injuries’ effects.
Severe multiple trauma is often associated with
traumatic lung injury. While the prehospital intubation of
patients with severe thoracic trauma without manifest
respiratory insufficiency has been debated [
Ruchholtz et al. reported that 95% of their severely
injured patients suffering from severe thoracic trauma
(AISThorax = 4), without prehospital intubation presented
the indication for intubation over the medium term .
Mechanical ventilation time and length of ICU stay in mean days for singular
or multiple chest trauma diagnoses
Subgroups according to the AISThorax (2, 3, 4, and 5 + 6)
In our population, 62 to 81% of patients admitted to the
ICU were already intubated, and most underwent
interventions (e.g., surgery) prior to their admission. In line
with others, we also detected higher rates of mechanical
ventilation at ICU admission in conjunction with higher
AISThorax scores [
]. Our severely injured patients were
mechanically ventilated for a mean 5.6 days—less time
than Hildebrand et al.’s severely injured patients
(mechanically ventilated for a mean 11 days) but comparable
to Sauaia et al. Those two working groups also excluded
severely injured patients with severe traumatic brain
]. Hildebrand et al. demonstrated a
greater increase in mechanical-ventilation days in
conjunction with each additional point in the
AISThorax than we did, but they only analyzed patients
with an AISThorax ≥ 3 ≤ 5 .
Our reported lengths of ICU stay falls within the range
of Sauaia et al. and Fröhlich et al. regarding their
populations of severely injured patients [
]. Compared to
Hildebrand et al., all our patients exhibit an almost
5-day shorter mean length of stay in the ICU, despite
similar ISS scores and overall mortality, exclusion of
severe head trauma in both studies, and our population’s
higher percentage of acute lung failure .
Interesting enough, we found no statistical significant
influence of more severe thoracic trauma (AISThorax ≥ 4)
on ICU length of stay, but a significant effect on
prolonging the mechanical ventilation period. When
breaking the AISThorax down into actual injuries to
thoracic structures, only fractures to the rib cage and
sternum significantly prolonged the ICU stay and
intubation. This is reflected in a scoring system where
patients suffering from thoracic trauma are, among
other parameters, assessed for the extent of rib fractures
to estimate the requirement of mechanical ventilation
and prolonged care [
We demonstrate with our severely injured patients
that not only the most severe injury to the chest—which
determines the AISThorax score—was pertinent to the
length of the intubation period, but also that the total
number of chest injuries influenced both, length of
mechanical ventilation and ICU stay. This may, again, be
reflected in the recently developed scoring system to
predict the outcome of patients with chest wall injuries
where parameters like age, extent of pulmonary
contusion, number of rib fractures, and existing bilateral rib
fractures are taken into account. Patients with total
scores ≥ 5 were mechanically ventilated and hospitalized
for a longer period, while those with scores ≥ 7 revealed
a still greater risk for mortality, ICU admission, and
mechanical ventilation [
]. However, we detected no
correlation between multiple injuries to the chest and
increased mortality in our study.
The 10.6% overall mortality we report falls within the
published range of in-hospital-mortality in a severely
injured population (9 to 16.2%) [
6, 19, 22
]. To the best of
our knowledge, AISThorax-dependent differences in
mortality have not been reported before. Interestingly, our
data reveal that single and multiple injuries resulting in
an AISThorax = 3 and 2 did not increase mortality
compared to AISThorax = 0 and 1 in our severely injured
patients. Perhaps lesser injuries to the chest, despite
increasing the rate of acute lung failure in our population,
Number of patients and percentage within the respective cohort of thoracic trauma severity are shown
Early mortality: death within 24 h after hospital admission
aParameter available only for patients documented with the standard form (n = 16,793; missing data in 13%); therefore, total patient numbers vary
do not inflict greater injury to the other organ systems,
and the body can recuperate. While the 10.9 to 40.3%
range of AISThorax-dependent acute lung failure we
report resembles the published incidence of 8 to 37% in
trauma patients [
], others have shown the
associated mortality to range from 16 to 29% [
An AISThorax ≥ 4 may exert widespread chest-trauma
effects throughout the body, thereby furthering the
development of multiple organ dysfunction and failure
and raising an independent risk factor for acute lung
injury (ALI), ARDS, and pulmonary failure [
Furthermore, it is well known that 80% of patients with
multiple organ dysfunction syndrome (MODS) start with
lung failure , and that severe thoracic trauma is an
independent risk factor for developing MODS [
MODS-related deaths range from 13 to 36% [
6, 7, 32
Our data support these findings, as we noted increasing
rates of respiratory failure with increasing thoracic
trauma severity, and demonstrate the first major rise in
MOF in association with an AISThorax ≥ 4. In the context
of sepsis, our reports are comparable to published rates
in severely injured patients, which range from 3.1 to
]. However, we also demonstrate that the severity
of thoracic trauma is associated with increasing sepsis
rates in severely injured patients.
We report different mean LOS for all severely injured
patients and surviving patients only. The mean LOS for
all patients is shorter than for surviving patients and
shortest for all patients with AIS-5/6. This is not
surprising, since per definition AISThorax = 6 is a not
survivable injury and many patients with AISThorax = 5 will
die because of the magnitude of injury. More striking is
the fact that across the AIS groups in surviving patients,
LOS seems not to differ. One explanation could be that
patients with lower AISThorax exhibit more serious
injuries in other body regions (e.g., abdominal, extremities)
responsible for longer hospitalization in these groups.
This is underlined by the fact that we only found a
tendency towards longer ICU stay with increasing
thoracic trauma severity, and this effect was not statistically
significant in our multiple linear regression analysis.
Another possibility is the early discharge of patients with
higher AISThorax for respiratory weaning/respiratory
rehabilitation, thus shortening the period of care in the
primary care facility documenting these cases.
When considering where death occurred, most of our
patients died in the ICU. However, an AISThorax < 4
incurred a higher rate of deaths on regular wards than
an AISThorax ≥ 4. We were unable to analyze the causes
of death in these different groups since they are not
documented in the TR-DGU’s primary data set. Thus,
we have too little knowledge to determine why, after
being discharged from the ICU, severely injured patients,
without severe head and severe thoracic trauma, had a
higher rate of death than patients with severe chest trauma.
The percentage of intubated, severely injured patients
admitted to the ICU has declined in recent years,
independent of the severity of their thoracic trauma. This
might be a reflection of prehospital behavior, where
changes over the last 20 years—from routine intubation
in most severely injured patients to intubation based on
clearer indications—has led to better care [
Moreover, in patients in whom the indication for mechanical
ventilation arose because of the accompanying thoracic
trauma, early non-invasive ventilation has proven to
significantly reduce mortality and the intubation rate
without increasing complications [
We publish a decline in the mortality rate of severely
injured patients in recent years irrespective of the severity
of the chest trauma they sustained. This observation
concurs with prior data reporting an overall drop in the
mortality of severely injured patients [
This study is limited by its retrospective nature.
Hospitals participating in the TR-DGU are regularly audited,
and sample tests are taken to ensure data quality.
However, the validity of their documentation is not verified by
external monitors as in prospective trials [
]. The present
analysis is based upon a European population where the
majority experienced blunt trauma, which might differ
from cohorts with a higher percentage of penetrating
injuries. Our interpretation of the causes of mortality is
limited by referring to the TR-DGU database, since the
actual cause of death is not recorded; thus, we could not
ascribe higher mortality rates to either inherent thoracic
(e.g., respiratory failure) or to other causes (e.g., sepsis,
MOF). Additionally, we excluded patients with severe head
injury (AISHead ≥ 4) in our study to minimize confounding
and, as a result, our findings cannot be readily transferred
to severely injured patients sustaining additional major
To interpret our results, one has to keep in mind that
our “control group” is mainly characterized by the
absence of relevant thoracic trauma (AISThorax ≤ 1).
Thus, to generate an ISS ≥ 16 without severe injury to
the head, patients needed at least one severe injury or a
combination of injuries to the remaining body regions.
Albeit, since we clearly focus on the influence of
thoracic trauma in severely injured patients, we feel this to
be an adequate “control group.”
The extent of thoracic trauma in severely injured patients
is a relevant risk factor for intensive care therapy, organ
failure, sepsis, and mortality. We demonstrate that the
higher the AISThorax score, the higher the rate of intubated
patients admitted to the ICU. Higher AISThorax scores and
multiple injuries to the chest correlated with longer
periods of mechanical ventilation and ICU stays. Mortality
in our population began to rise in conjunction with an
AISThorax ≥ 4. Overall, while most patient deaths occurred
during their ICU stay, death later than 3 days after ICU
discharge occurred more often in patients with milder
chest injuries (AISThorax ≤ 3).
AIS: Abbreviated injury scale; ALI: Acute lung injury; ARDS: Adult respiratory
syndrome; ICU: Intensive care unit; ISS: Injury severity score; LOS: Length of
hospital stay; MODS: Multiple organ dysfunction syndrome; MOF: Multiple
organ failure; NISS: New ISS; SD: Standard deviation; TBI: Traumatic brain
injury; TR-DGU: The TraumaRegister DGU®
The authors thank Carole Cürten for language editing.
Participating hospitals are listed in alphabetical order under
The article processing charge was funded by the German Research
Foundation (DFG) and the Albert-Ludwigs-University Freiburg in the funding
program Open Access Publishing.
Availability of data and materials
The datasets used and/or analyzed during the current study are available
from the corresponding author on reasonable request.
JB conceived and designed the study, interpreted the data, and drafted the
manuscript. RL was in charge of the statistical reports. RL, SR, JK, JZ, NS, and
TH contributed to the study design, interpreted the data, and critically
revised the manuscript. All authors read and approved the final manuscript.
Ethics approval and consent to participate
The study was approved by the University of Freiburg Ethics Committee
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