Blunt Thoracic Trauma
Even for those of us who deal with blunt trauma on a daily basis,
a report from the field that a high speed collision has occurred
with a victim who has sustained a "steering wheel injury" raises
our overall level of concern. The management of thoracic trauma,
with its attendant potential for life threatening injury, if
approached from the standpoint of providing an airway, assuring
adequate ventilation and controlling hemodynamics falls within
the realm of all anesthesiologists.
When evaluating the airway in a patient with blunt thoracic
trauma, one must look for associated injuries to the head, face,
cervical spine and injuries to the upper and lower airway. Low
level of consciousness, airway obstruction or disruption, and
inability to oxygenate the patient by mask indicate the need
for tracheal intubation. Blood in the airway, recent food intake,
and trauma itself with decreased gastric emptying, mandate an
approach which minimizes the potential for aspiration of gastric
contents. Awake techniques with direct visualization, i.e. fiberoptic
or direct laryngoscopy, or rapid sequence induction with cervical
immobilization may be appropriate depending on the clinical
scenario and level of skill of the anesthesiologist.
A careful physical assessment of the ventilatory function of
the thoracic trauma victim should include inspection for respiratory
rate, presence of paradoxical motion of the chest wall, or obvious
chest wounds. Palpation of the chest should seek pain, crepitus
or subcutaneous emphysema as clues to underlying pathology.
The auscultation of the lung fields may detect a pneumothorax
or hemothorax before a chest xray may be performed, as well
as assessing the adequacy of air entry. Percussion although
theoretically of use in differentiating between pneumo and hemothorax
may be practically difficult in the atmosphere surrounding a
typical resuscitation bay.
Since hypotension in thoracic trauma
is usually associated with hypovolemia it should be aggressively
treated initially with volume expansion with crystalloids while
other possible etiologies, i.e. pneumothorax, cardiac tamponade
and blunt cardiac injury are assessed. The presence of arrhythmia
should raise suspicion of blunt cardiac injury.[2, 3]. Hypertension
may dramatically worsen bleeding in thoracic trauma and may
dislodge thrombus which is containing a major vessel disruption
and therefore should be treated. Two large bore peripheral IV's
are a minimum for resuscitation and a central access is usually
needed both for therapy and monitoring.
The usual laboratory tests, complete blood count, electrolytes,
glucose, BUN, creatinine, urinalysis, ECG, and blood type and
crossmatch should be obtained.
The chest xray is of paramount importance in thoracic trauma
and only attention to life threatening problems should delay
obtaining it.. Systematic review of the radiograph may reveal
both suspected and unsuspected pathology. The bony thorax including
ribs, clavicles, scapulae, and vertebrae, should be examined
for fracture. Soft tissues should be evaluated for emphysema
or opacification. The lung fields may likewise demonstrate pneumothorax,
hemothorax, consolidation suggestive of lung contusion. Radiographic
abnormalities of the mediastinum, particularly pneumomediastinum,
widening of the mediastinum, or shift of the mediastinum suggest
airway rupture, aortic disruption, and tension pneumothorax
respectively. Finally assessment of the cardiac silhouette may
aid in the diagnosis of blunt myocardial injury including tamponade.
In addition to the lateral cervical spine and pelvis films which
are generally obtained for every blunt trauma victim, several
imaging examinations are of particular interest in the work
up of thoracic trauma. The echocardiogram, either precordial
or transesophageal, is useful in evaluating for pericardial
fluid, valve and wall motion, and the presence and extent of
aortic disruption. Computerized tomography of the chest may
reveal aortic disruption and pneumothorax not readily apparent
on plain chest xray. Finally, arteriography is used to precisely
locate vascular injury.[4, 5]
Rib fractures should be taken in context. Their presense indicate
a need for examining the underlying lung for contusion, laceration,
hemo or pneumothorax. Multiple or anterior and posterior rib
fractures may cause a flail segment. Fracture of the relatively
protected first through third ribs indicates severe impact and
mandates careful search for associated injury.
Pulmonary contusion frequently manefests itself as hypoxemia.
the goals for treatment are oxygentherapy, positive pressure
either with a CPAP mask or by intubation and mechanical ventilation
with PEEP. Splinting from the pain associated with rib fractures
requires adequate pain management, i.e.parenteral narcotics,
interpleural local anesthetics, or epidural narcotics/local
anesthetics. The contused lung is prone to capillary leak and
therefore careful fluid management is indicated.
A high index of suspicion for the presence of a pneumothorax
must be maintained in all blunt trauma victims. Auscultation
may be difficult in the ER. Other signs of tension pneumothorax,
tracheal deviation, hypotension, hypoxemia should trigger chest
decompression prior to CXR. If the patient is stable an xray
may preceed the thoracostomy. Patients with multiple rib fractures
may harbor a subclinical pneumothrax and may require "prophylactic"
thoracostomy prior to OR.
Up to 40% of the blood volume can be accomodated in one hemothorax.
1500 ml of initial blood output in chest tube drainage is an
indication for thoracotomy as a large vessle or cardiac rupture
may be present. Bronchial injury Blunt injury to the lower
airways is usually caused by deceleration or compression injury.
These injuries typically present as either a pneumothorax which
doesn't resolve or a persistent air leak with tube thoracostomy.
While rare, (0.4% of 515 patients in one study) tracheal
or bronchial injury poses management issues for the anestheiologist.
Fiberoptic evaluation of the airway may serve as a guide for
intubation as well as aid in the location of injury for surgical
correction. Lung isolation procedures are frequently employed
A widened mediastinum on chest xray in the blunt trauma victim
is usually associated with aortic injury. Several technical
factors of the AP portable films taken in the emergency setting,
i.e. supine position, expiratory film, and the magnification
effect of a short beam distance, may make the mediastinum appear
widened. Loss of the aortic knob contour, shift of the esophagus
(nasogastric tube) to the right and an apical cap in addition
to mediastinal widening indicate need for further workup.[4,
80-90% of patients with thoracic aortic rupture die in the pre-hospital
setting. Those who survive to to reach the hospital may have
minimal symptoms. The chest film may give the first suggestion
of injury. The rupture is usually at the isthmus just distal
to the left subclavian artery. Control of blood pressure is
critical to avoid further dissection. Emergent surgery with
poor hemodynamic stabilization has high mortality.[5, 9]
to Thoracic Aortic Tear
Monitors: Routine plus invasive right sided aline, femoral aline,
large bore CVP, pulmonary cath, TEE
Large bore intravenous lines with fluid warmers
Induction strategy which minimizes hemodynamic changes.
Double lumen tube for lung isolation
Control of proximal hypertension during crossclamp vasodilators/beta
blockers limit intravenous fluids
Control of hypotension after release of clamp with fluid loading
and tapering of vasodilator.
Strategies for renal/spinal preservation: short crossclamp,
shunt, atriofemoral bypass, femoral vein-femoral artery bypass,
Pain control epidural? [5, 9, 10]
Blunt Cardiac Injury
Blunt trauma to the heart covers the spectrum of myocardial
concussion,contusion to myocardial rupture. The right atrium
and ventricle are the most frequently injured chambers because
of their anterior positioning in the chest, followed by left
atrium and left ventricle. Survival from one chamber rupture
is about 40% . Two chamber rupture has uniform mortality. Once
again echocardiaography is extremely useful in the diagnosis
of this injury.
Patients with suspected myocardial contusion are no longer routinely
subjected to prolonged observation in a monitored setting. If
the ECG and echocardiogram are normal the patient may go home
after 12 hours if no other injuries are present. Young patients
rarely have cardiac related complications even when cardiac
contusion is diagnosed. The best test for diagnosis remains
controversial. The ECG is unreliable unless ST elevation is
present. CPK MB isoenzymes may be nondiagnostic. Cardiac troponin
I which may be more specific for myocardial damge has not been
adequately evaluated. Echocardiography is useful for detecting
wall motion abnormalities, pericardial effusions and in combination
with abnormal CPK MB may predict complications. Radionuclide
angiography may also be predictive of complication. Thallium
scanning can detect areas of decreased perfusion, but cannot
differentiate an acute from preexisting lesion[3, 12]
Pericardial tamponade should be suspected when there is hypotension
unexplained by other findings ie tension pneumothorax, hemothorax,
abdominal or other hemorrage. Neck vein distention may be masked
by the cervical collar. Echocardigraphy is probasbly the best
diagnostic tool. If a PA catheter is present equalization of
pressures may be seen. Prompt drianage via pericardial window
is the best treatment. This procedure may be performed with
local anesthesia. Hemodynamic changes are minimized with the
spontaneously breathing patient. Underlying injury may be ruptured
heart, aortic disruption, or myocardial contusion without rupture.[1,
The symptoms of diaphragmatic rupture are similar to pneumothrax
as the lung is compressed and hypoxemia developes. Diagnosis is
made with the chest xray. Loss of the diaphragmatic countour,
presense of bowel or NG tube in the chest or elevaton of the right
hemidiapragm are all suggestive. Intubation and mechanical ventilation
are needed for adequate oxygenation. Hemothorax may be from a
ruptured spleen.[1, 4]
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