Pattern And Severity of Injury in Avalanche Victims

Abstract

In avalanche accidents, the significance of major trauma as a cause of morbidity and mortality is controversial. The aim of this retrospective study is to determine the severity and pattern of injury in avalanche victims admitted to the University Hospital of Innsbruck between 1996 and 2005. A total of 49 significant injuries were found in 105 avalanche victims; the most frequent were of the extremities (n = 20), the chest (n = 18), and the spine (n = 7). In contrast, cerebral (n = 2), abdominal visceral (n = 1), and pelvic trauma (n = 1) were rare. The severity of injury was minor or moderate in most patients, with only 9 (8.6%) being severely or critically injured. Of 105 (34.3%) avalanche victims, 36 died. Autopsy was performed in 30 of 36 nonsurvivors. The cause of death in the remaining 6 victims was concluded from clinical, radiological, and electrophysiological findings. Trauma was responsible for deaths of only 2 avalanche victims (5.6%); both had cervical spine fractures with dislocation leading to death. One death was due to hypothermia, whereas the remaining 33 fatalities (91.7%) were due to asphyxia. The incidence of life-threatening or lethal trauma was well below 10%. Asphyxia is by far the most important reason for death. Deaths from trauma were solely due to isolated cervical injuries, demonstrating that the cervical spine may be a region at particular risk in avalanche victims.

Full text

1
Department of Anesthesiology and Critical Care Medicine, Medical University Innsbruck, Innsbruck, Austria.
2
President, International Commission for Mountain Emergency Medicine/ICAR MEDCOM, Mountain Rescue Ser-
vice, South Tyrolean Alpine Association, Bruneck, Italy.
3
Austrian Mountain Rescue Service, Klagenfurt, Austria.
4
Department of Trauma Surgery and Sports Traumatology, Medical University Innsbruck, Innsbruck, Austria.
5
Institute of Legal Medicine, Medical University Innsbruck, Innsbruck, Austria.
6
International Commission for Mountain Emergency Medicine, ICAR MEDCOM, Mountain Rescue Council En-
gland and Wales, Penrith, Cumbria, England.
56
INTRODUCTION
A
PPROXIMATELY
100
TO
150
PEOPLE
die each
year in avalanche accidents in Europe and
North America (Brugger et al., 1997). It is
widely assumed that asphyxia is the cause of
death in a majority of them (Falk et al., 1994;
Brugger et al., 2001; Brugger et al., 2003). How-
ever, major injuries in avalanche victims have
been reported, including blunt abdominal,
pelvic, chest, and head trauma (Grossman et
al., 1989; Stalsberg et al., 1989; Johnson et al.,
HIGH ALTITUDE MEDICINE & BIOLOGY
Volume 8, Number 1, 2007
© Mary Ann Liebert, Inc.
DOI: 10.1089/ham.2006.0815
Pattern and Severity of Injury in Avalanche Victims
MATTHIAS HOHLRIEDER,
1,3
HERMANN BRUGGER,
2
HEINRICH M. SCHUBERT,
4
MARION PAVLIC,
5
JOHN ELLERTON,
6
and PETER MAIR
1,3
ABSTRACT
Hohlrieder, Matthias, Hermann Brugger, Heinrich M. Schubert, Marion Pavlic, John Ellerton,
and Peter Mair. Pattern and severity of injury in avalanche victims. High Alt. Med. Biol. 8:56–61,
2007.—In avalanche accidents, the significance of major trauma as a cause of morbidity and mor-
tality is controversial. The aim of this retrospective study is to determine the severity and pat-
tern of injury in avalanche victims admitted to the University Hospital of Innsbruck between
1996 and 2005. A total of 49 significant injuries were found in 105 avalanche victims; the most
frequent were of the extremities (n20), the chest (n18), and the spine (n7). In contrast,
cerebral (n2), abdominal visceral (n1), and pelvic trauma (n1) were rare. The severity
of injury was minor or moderate in most patients, with only 9 (8.6%) being severely or critically
injured. Of 105 (34.3%) avalanche victims, 36 died. Autopsy was performed in 30 of 36 nonsur-
vivors. The cause of death in the remaining 6 victims was concluded from clinical, radiological,
and electrophysiological findings. Trauma was responsible for deaths of only 2 avalanche vic-
tims (5.6%); both had cervical spine fractures with dislocation leading to death. One death was
due to hypothermia, whereas the remaining 33 fatalities (91.7%) were due to asphyxia. The in-
cidence of life-threatening or lethal trauma was well below 10%. Asphyxia is by far the most im-
portant reason for death. Deaths from trauma were solely due to isolated cervical injuries, demon-
strating that the cervical spine may be a region at particular risk in avalanche victims.
Key Words: avalanche; asphyxia; autopsy; death; injury; mountain; spinal injury; trauma

TRAUMA IN AVALANCHE VICTIMS 57
2001). The incidence of life-threatening or lethal
trauma has been estimated between 4% (Eli-
akis, 1974) and 50% (Grossman et al., 1989). Al-
though our understanding of the mechanism of
death after snow burial in avalanche accidents
has improved during the last years (Falk et al.,
1994; Brugger et al., 2003), the significance of
major trauma in the morbidity and mortality of
avalanche accidents is still controversial.
Therefore, the purpose of this retrospective
study was to assess the incidence of major
trauma, as well as the particular pattern of in-
jury in avalanche victims.
METHODS AND PATIENTS
The University Hospital of Innsbruck pro-
vides a level I trauma center serving several
popular off-piste ski resorts and backcountry
ski areas in the Austrian Alps. During the 10-
yr period between 1996 and 2005, a total of 105
individuals involved in an avalanche accident
were admitted either to the emergency room of
the Trauma Center of the University Hospital
or to the university-affiliated Institute of Legal
Medicine. The medical diagnoses established
during hospital treatment or the results of the
autopsy were obtained for each identified case.
All injuries diagnosed were graded using the
Abbreviated Injury Scale (AIS) and the Injury
Severity Scoring system (ISS) (Van Camp,
2001). The AIS is a consensus-derived, anatom-
ically based system that allocates each injury to
one of six body regions (head and neck, face,
chest, abdomen, extremity, external) and clas-
sifies them on a 6-point severity scale, ranging
from score 1 to 6 (minor, moderate, serious, se-
vere, critical, unsurvivable). The ISS takes into
account the combined effect of individual in-
juries and is calculated from the AIS scores of
the three most severely affected body regions
(Baker et al., 1974). ISS scores between 1 and 7
are considered as minor injury, 8 to 13 as mod-
erate injury, 14 to 20 as severe multisystem
trauma, and more than 20 as critical multisys-
tem trauma (Collopy et al., 1992). To classify
the pattern of injury, only major fractures and
dislocations and injuries with an AIS severity
score equal to or more than 3 were considered
significant and used for analysis.
For each of the 105 victims, any data relating
to the circumstances of the accident were also
collected from the accident reports of the
mountain rescue service and the mountain po-
lice squad. Where insufficient information was
available, one of the authors directly contacted
the victim to obtain the missing data. The ac-
cident data collected included the type of ac-
tivity (skier, snowboarder, mountaineer), type
of burial (totally buried or partially buried),
and depth of burial. A victim was considered
totally buried when head and chest were cov-
ered by the snow of the avalanche, regardless
of whether other parts of the body or pieces of
the victim’s equipment were visible on the de-
bris surface.
Statistical analysis
Means, standard deviations, and ranges
were calculated to describe continuous vari-
ables. Chi-square test was used for statistical
analysis. A p-value below 0.05 was considered
significant.
RESULTS
The mean age of the victims was 38.4 14.6
yr; 85 of them (81%) were male. Most of the vic-
tims were skiers (76.2%); the remaining were
snowboarders (15.2%) or mountaineers (8.6%).
Sixty-seven avalanche victims (63.8%) were to-
tally buried, with a mean depth of burial of
1.1 0.8 meters. Thirty-seven of the 67 totally
buried avalanche victims (55.2%) were in car-
diac arrest when rescued out of the snow.
Patient management and outcome
Eleven of the 105 avalanche victims (10.5%)
were already pronounced dead by the emer-
gency medical service in the prehospital envi-
ronment and directly transferred to the Insti-
tute of Legal Medicine for autopsy. Ninety-four
avalanche victims (89.5%) were admitted to the
hospital emergency room (Fig. 1). Eleven of
them, all undergoing prolonged resuscitation
efforts, were pronounced dead in the emer-
gency room according to ICAR MEDCOM cri-
teria (Brugger and Durrer, 2002) and subse-
quently transferred to the Institute of Legal

58 HOHLRIEDER ET AL.
Medicine for autopsy. Sixty-two avalanche vic-
tims had injuries or medical problems severe
enough to be admitted to hospital, including 5
who were treated with extracorporeal circula-
tion. The remaining 21 avalanche victims were
uninjured or had minor injuries and were dis-
charged from hospital without admission.
Fourteen of the 62 patients admitted to hospi-
tal died during their hospital stay, and 8 were
transferred to the Institute of Legal Medicine
for autopsy. One of the 5 patients rewarmed by
means of extracorporeal circulation survived.
Severity and pattern of injury
Of 105 patients (74.3%), 78 had no or only
minor injuries (ISS 8). Eighteen patients
(17.1%) were moderately (ISS 8–13), 2 patients
(1.9%) severely (ISS 14–20), and 7 patients
(6.7%) critically injured (ISS 20). A total of 49
significant injuries (AIS score 3) were diag-
nosed (Table 1). Fractures of the extremities
were most frequently present, with a remark-
ably high rate of lower leg fractures (n8) and
shoulder dislocations (n6). Chest trauma
was also common (n18). However, the ma-
jority of rib and sternum fractures (12 of 16,
75.0%) occurred in patients with a history of
CPR and were considered as resuscitation-as-
sociated injuries at autopsy. Spine fractures
were diagnosed in 7 patients (6.7%), of which
three occurred in the cervical region. Major
cerebral, abdominal visceral, or pelvic trauma
was rare.
Cause of death
Of the 105 (34.3%) avalanche victims, 36
died. One (2.8%) died of hypothermia, which
was primarily diagnosed by the finding of Wis-
Avalanche Victims
105
Admitted to ER
94
Pronounced dead by EMS
11
Hospitalization
62
Outpatient treatment
21
Pronounced dead in ER
11
Survived
48
Dead
14
FIG. 1. Patient management and outcome: ER, emergency room; EMS, emergency medical service.
T
ABLE
1. P
ATTERN OF
I
NJURY IN
105 A
VALANCHE
V
ICTIMS
Trauma Frequency (n)
Cerebral trauma (n2)
Chest trauma (n18)
Sternum or rib fracture n16
Pneumothorax/hematothorax n6
Spine fracture (n7)
Cervical n3
Thoracic n1
Lumbar n3
Abdominal trauma (n1)
Pelvic fracture (n1)
Extremity trauma (n20)
Lower leg fracture n8
Shoulder dislocation n6
Femur fracture n4

TRAUMA IN AVALANCHE VICTIMS 59
chnewsky’s spots in the mucosa of the stom-
ach, a well-known sign of death due to hy-
pothermia. Two victims (5.6%) suffered from
lethal, isolated cervical spine fracture with dis-
location. In the remaining 33 avalanche vic-
tims (91.7%), asphyxia was determined as the
cause of death, based on a combination of
signs, such as right cardiac ventricle dilatation;
brain edema; small pleural hemorrhages; or
petechial, conjunctival, or oral mucosa bleed-
ing. Autopsy was performed in 30 of 36 non-
survivors. The cause of death in the remain-
ing 6 victims was concluded from clinical, ra-
diological, and electrophysiological findings,
whereby the presence of major trauma could
reliably be excluded in all.
DISCUSSION
The incidence of life-threatening or lethal
traumatic injury was well below 10% in this ret-
rospective review of 105 individuals involved
in avalanche accidents in the Austrian Alps.
Many uninjured or mildly injured avalanche
victims will not be admitted to a hospital, so
the actual incidence of significant trauma in
avalanche accidents will be even less.
Our findings are in accord with several pre-
vious publications indicating that significant
trauma is rare (Lugger and Unterdorfer, 1972;
Eliakis, 1974; Lapras, 1980; Stalsberg et al., 1989;
Rostrup and Gilbert, 1993). However, Grossman
et al. (1989) found evidence for severe multisys-
tem trauma contributing to fatal outcome in 50%
of all avalanche victims admitted to hospital in
cardiac arrest in Utah (USA). But diagnosis of
lethal trauma was not confirmed by autopsy,
raising doubts whether trauma was definitely
the main reason for the fatal outcome. On the
other hand, the incidence of lethal trauma may
vary markedly among various publications be-
cause of differences in the type of avalanche, ter-
rain, snow density, and presence of obstacles
like trees and rocks. Catastrophic avalanches af-
fecting people in buildings or avalanches affect-
ing climbers and mountaineers on steep and ex-
posed terrain will have a markedly higher rate
of lethal trauma when compared to avalanche
accidents involving activities on moderate or
steep ski slopes.
Nevertheless, the majority of data on ava-
lanche accidents during recreational activities
clearly indicate that lethal mechanical trauma
is rare. This is of major importance, as the
recommended safety equipment is not aimed
at preventing injury, but only at avoiding
asphyxia by reducing the depth of burial
(Airbag-System™, Mountain Safety Systems
Ltd., Whistler, Canada), by reducing the time
of burial (avalanche transceivers), or by pro-
longing the survival after burial (AvaLung-Sys-
tem™, Black Diamond Equipment, Salt Lake,
Utah).
Apart from chest injuries, lower leg fractures
and shoulder dislocations were the most com-
mon injuries in our study population. It is very
likely that these injuries were caused by the
forces of the moving snow acting on skis (or
snowboard) and poles fixed to the victim’s ex-
tremities. Not only do they predispose to or-
thopedic trauma, but they may also act as an
anchor, increasing the depth of snow burial. It
is widely accepted among skiers and boarders
that getting rid of skis, boards, and poles is
good when you are caught in an avalanche.
Severe, isolated cervical spine injury caused
both cases of trauma-related death in our study
population. Both victims were involved in
avalanche accidents while backcountry skiing
in moderately steep terrain and were totally
buried. Neither of them had a history of a ma-
jor fall over rough terrain. We assume that hy-
perextension and hyperflexion trauma of the
cervical spine during the avalanche resulted in
the lethal neck trauma. Lapras (1980) and Lug-
ger and Unterdorfer (1972) also found occa-
sional cases with severe cervical spine injury in
their reports on avalanche trauma, indicating
that the neck may be a region at particular risk.
Recently the airbag concept has been devel-
oped with the aim of stabilizing the neck, as
well as reducing the chances of complete bur-
ial. Preliminary experimental data on the vest
(Avagear™, Avagear INC., San Francisco, CA)
demonstrated that it can reduce the forces act-
ing on the neck during avalanche descent (Kern
and Schweizer, 2001) and so may represent an
improvement of the airbag system. Rescue ser-
vices involved in the rescue of avalanche vic-
tims should consider whether the routine use
of cervical immobilizing collars (e.g., Stiff-

60 HOHLRIEDER ET AL.
neck™, Laerdal Medical Corporation, New
York) would be appropriate, particularly for
those who were totally buried.
The incidence of severe cerebral trauma was
2% in our study population. By contrast, John-
son et al. (2001) reported a 61% incidence of all
types of head trauma for avalanche victims in
Utah (USA), with 21% sufficiently severe to
cause death. Collision with obstacles such as
trees during the avalanche descent is excep-
tionally rare in the Alps, but a common mech-
anism for injury in avalanche accidents in some
regions of North America (personal communi-
cation). The difference in terrain between the
Alps and the Rocky Mountains is the most
likely explanation for the observed difference
in the incidence of major head trauma. Fur-
thermore, head injury, although not directly
lethal, may reduce consciousness, thereby im-
pairing important survival techniques, such as
“swim movements,” creating an air pocket
with the hands, or using a breathing device
(Avalung™, Black Diamond Equipment), and
so increase the risk of death from asphyxia.
General body compression by the snow has
been reported to cause respiratory failure and
death in avalanche victims (Stalsberg et al.,
1989). The firm generalized pressure exerted
by the avalanche debris may also cause sig-
nificant chest trauma in a few avalanche vic-
tims. However, in the vast majority of vic-
tims, rib and sternum fractures appear to
have been caused by external cardiac mas-
sage during the resuscitation efforts. The re-
markably high incidence of resuscitation-as-
sociated thoracic injuries may be explained
by hypothermia-induced stiffness of the tho-
rax (Mair et al., 1998). Cardiopulmonary re-
suscitation after avalanche accidents is often
prolonged and performed under difficult en-
vironmental conditions, thus predisposing
the victim to these resuscitation-associated
complications. It should be noted that these
significant chest injuries can be particularly
detrimental to the cardiovascularly unstable,
hypothermic avalanche victims, because an-
ticoagulation during extracorporeal rewarm-
ing may result in intractable bleeding.
Another mechanism for major trauma in
avalanche accidents may be a fall over steep,
exposed terrain or the collision with trees or
rocks as the avalanche carries the victim. This
is most likely a leading reason for significant
multisystem trauma in our study population;
typically, these injuries were found in ava-
lanche victims only partially buried, but with
a history of a large fall over rough terrain dur-
ing the avalanche. In a previous study, Stals-
berg et al. (1989) also found that mechanical in-
jury was strikingly more common in partially
buried avalanche victims compared with those
who were totally buried.
In this retrospective study, we only included
avalanche victims admitted to the University
Hospital of Innsbruck. We undoubtedly missed
a significant number of uninjured or mildly in-
jured avalanche victims not seeking medical
help or those being admitted to small hospitals.
Therefore, our study population will overesti-
mate the actual incidence of major trauma in
avalanche victims. Furthermore, one might ar-
gue that avalanche victims with obvious lethal
trauma are neither resuscitated nor transferred
to a hospital and therefore will not be included
in our study. To exclude this bias, we searched
all accident reports of the Austrian Mountain
Rescue Service during the study period for
avalanche victims pronounced dead at the
scene because of obvious lethal trauma. Thus
we can rule out that we missed a consider-
able number of avalanche victims with lethal
trauma.
CONCLUSION
The incidence of life-threatening or lethal
trauma was well below 10% in avalanche vic-
tims admitted to our institution, confirming
that asphyxia, not trauma, is by far the most
important pathology in those victims with
significant injury or illness. Lethal trauma in
our study was solely due to isolated severe
cervical injuries, indicating that the cervical
spine may be a region of particular risk dur-
ing the course of an avalanche. Critical mul-
tisystem trauma is often found in avalanche
victims only partially buried by the snow,
but with a history of a large fall over rough
terrain.

TRAUMA IN AVALANCHE VICTIMS 61
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Address reprint requests to:
Matthias Hohlrieder
Dept. of Anesthesiology and
Critical Care Medicine
Medical University Innsbruck
Innsbruck, Austria
E-mail: matthias.hohlrieder@i-med.ac.at
Received March 29, 2006; accepted in final
form September 8, 2006.