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Mechanism of Injury
For penetrating thoracic injury the survival rate
is fairly uniform at 18-33%, with stab wounds having
a far greater chance of survival than gunshot wounds.
Isolated thoracic stab wounds causing cardiac tamponade
probably have the highest survival rate, approaching
70%. In contrast, gunshot wounds injuring more than
one cardiac chamber and causing exsanguination have
a much higher mortaility.
Blunt trauma survival rates vary between 0 and 2.5%
and some authorities suggest that thoracotomy for blunt
trauma should be abandoned altogether. However, this
is an oversimplification of the literature. There is
a distinct survival rate for patients with isolated
blunt thoracic trauma who undergo emergency thoracotomy.
This is highest for patients who are severely hypotensive
in the emergency room and are exsanguinating from a
chest injury. Blunt thoracic trauma causing traumatic
arrest in the emergency department should also undergo
thoracotomy. Whether this should be extended to those
patients arresting in the presence of prehospital emergency
services is debatable.
Location of Injury
Almost all survivors of emergency thoracotomy suffer
isolated injuries to the thoracic cavity. Cardiac injuries
have the highest survival rates, with improved outcome
for single chamber versus multiple chamber injuries.
Injuries to the great vessels and pulmonary hila carry
a much higher mortality. Injuries to the chest wall
rarely require emergency thoracotomy but tend to have
a good outcome.
The rationale for performing thoracotomy for injury
to other parts of the body, such as the abdomen or pelvis,
is to cross-clamp the descending aorta and so control
exsanguination and redistribute blood flow to the vital
organs. Penetrating injury to the abdomen may benefit
from this manoeuver but thoracotomy for multiple blunt
trauma has an almost universally poor outcome.
Presence of vital signs
The presence of cardiac activity, or the amount of
time since loss of cardiac activity is consistently
related to the outcome following emergency thoracotomy.
In one study of 152 patients (Tyburski) survival rates
were 0% for those patients arresting at scene, 4% when
arrest occurred in the ambulance, 19% for emergency
department arrest and 27% for those who deteriorated
but did not arrest in the emergency department.
Survival for blunt trauma patients who never exhibited
any signs of life is almost uniformly zero. Survival
for penetrating trauma patients without signs of life
is between 0 and 5%.
Karim
Brohi, trauma.org 6:6, June 2001
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