Transcript Asphyxiation: a review

Asphyxiation: a review
Claire Richards and Daniel N Wallis
Trauma 2005;7:37-45
Intern 蔡巧榆
Traumatic asphyxia
Incidence and Etiology
Traumatic asphyxia is a rare condition when
considering the numbers of major trauma victims
seen in emergency departments, although this may
be because many cases are unrecognized or
unreported.
Laird and Borman found only seven cased out of
107000 hospital and clinic patients in a 30-month
period, of whom 75000 had been involed in major
accidents.(1930)
Dwek reported only one case out of a total of 18500
accident victims in an area with heavy military traffic.
(1946)
Incidence and Etiology
A heavy load to the thoracoabdominal region, such as
being pinned or crushed by a vehicle or piece of
heavy machinery is the commonest cause.
In 35 cases of traumatic asphyxia seen over a 5-year
period in New Mexico, 14(40%) were due to road
traffic accidents where the patient was ejected from
the vehicle and then crushed as it rolled over them.
The syndrome has also been described following
unsuccessful suicide attempts by hanging, blast injury,
asthma attack, diving, epileptic seizures, violent
vomiting and difficult obstetric delivery.
Incidence and Etiology
In experiments on guinea pigs and dogs the
incidence of death due to traumatic asphyxia is a
function of absolute weight and duration of
compression.
There is great variation in the amount and duration
of application of force required to produce the
characteristic featured of this condition, and in some
cases to cause death.
Death in cases of prolonged compression is
presumably caused by hypoxic cardiac arrest due to
complete restriction of respiratory movements.
Clinical features
The skin of the face, neck and upper torso may
appear blue-red to blue-black but it blanches.
The discolouration and petechiae are often more
pronounced on the eyelids, nose and lips.
These petechiae also usually blanch, and increase in
intensity in the first few hours but then fade over
days to weeks.
The subconjunctival hemorrhage, which almost
always occurs, and is considered to be due to the
relative lack of tissue support around this area, fades
slowly and disappears.
Clinical features
Exophthalmos occurs in 20% of cases and this also
slowly resolves fully.
There may be periorbital edema and ecchymosis.
Other mucous membranes that lack tissue support
such as the buccal mucosa, undersurface of the
tongue, palate and pharynx commonly show
petechiae or ecchymoses.
Epistaxis is often present and hemotympanum has
also been described.
Associated injuries include pulmonary, cardiac,
neurological, ophthalmic, abdominal and orthopaedic
injury.
Clinical features
Pulmonary injuries are those most commonly
associated with traumatic asphyxia and are the most
serious, including pulmonary contusion, pneumoand/or hemothorax and lung lacerations.
The most common neurological consequences are
transient loss of consciousness and confusion, which
may be prolonged but are generally self-limiting.
There may also be agitation, disorientation and
restlessness.
Clinical features
Abdominal injuries include liver and/or splenic
lacerations and gastrointestinal hemorrhage due to
blunt abdominal trauma. Diaphragmatic rupture is
another complication that has been described.
Transient microscopic hematuria and proteinuria may
occur due to increased venous pressure in the
kidneys.
Orthopaedic injuries include fracture of the clavicle,
long bones, pelvis and vertebrae.
Differential diagnosis
The diagnosis of traumatic asphyxia syndrome
is usually evident, based on history and the
striking characteristic clinical features.
However, features of SVC obstruction and
basilar skull fracture closely resemble the
appearances of traumatic asphyxia, in particular
the subconjunctival hemorrhages, periorbital
ecchymosis, epistaxis and hemotympanum.
Differential diagnosis
However, the history of traumatic injury
would rule out SVC obstruction, and skull
fractures are very rare in traumatic saphyxia
because the force of compression is not
applied to the head.
In addition, the venous pressure in the head
and neck is normal in traumatic asphyxia
after thoracic compression has been relieved,
in contrast to patients with SVC obstruction.
Treatment
Management of these patient is supportive, and
treatment is aimed at associated injury.
The mainstay of treatment is oxygenation, and
elevation of the head of the bed to 30。once the
spine has been cleared of injury.
Oxygen has almost no effect, however. On the
resolution of the facial discoloration.
Patients should be admitted initially to an ICU for
observation.
Treatment
Supportive ventilation may be required of there is
significant underlying pulmonary injury, chest wall
damage or respiratory depression due to cerebral
hypoxia.
If a significant crush injury has been sustained,
treatment with fluids, mannitol and bicarbonate
must be given as necessary to prevent renal failure
secondary to rhabdomyolysis.
Since the probability of associated injury is high, the
physical assessment of the patient must be
thorough, if other injuries are not to be missed with
potentially disastrous consequences.
Thanks for your attention!
Prognosis
Long-term follow-up of patients who have survived
traumatic asphyxia shows there are no long-term
sequelae from the condition itself; morbidity and
mortality are from associated injuries.
There are determined by the severity, nature and
duration of the compressive force.
The prognosis of those with traumatic asphyxia alone
is excellent if the patient survives to reach the
emergency department, despite their rather startling
appearance.
Approximately 90% of patients without associated
injury and surviving one hour after crush injury will
recover.