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Introduction
• Trauma leading cause of death in
developing countries | 4th in first-world
countries
• Loss of productive years of life – because
most occur in young individuals
• Traffic accidents, falls, recreational,
violence
• Rapid diagnosis important to avoid
morbidity and mortality
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Introduction
• Thoracic injuries
– 10-15% of all trauma
– 25% of trauma fatalities
• Blunt (70-80%) > penetrating
– Compression thoracic wall injuries
– High velocity injury visceral injuries
• Rx mostly conservative. Thoracotomy rate...
– <10% in blunt thoracic trauma
– 15-30% in penetrating thoracic trauma
Image from http://www.veomed.com/va041842172010
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Flail Chest
• Most significant chest wall injuries
• Paradoxical movement of a segment
of chest wall
• Problems of underlying lung contusion
and pain leading to hypoxia
• 3 or more contiguous segmental rib
fractures
• Variations include anterior flail,
posterior flail and flail including
sternum
• CXR may not show all fractures, esp
anterior and lateral fractures
Images from wikipedia
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Hemothorax
• Blood in pleural space
• Source: chest wall, lung
parenchyma, heart or great vessels
• Chest wall injuries can cause
bleeding from intercostal and IMA
• As much as 1,000 mL of blood may
be missed when viewing portable
supine CXR (400-500 mL required
for blunt CP angle on upright CXR)
• Massive hemothorax
– >1,500 mL of blood or
– > 1/3 of blood volume
Supine CXR: apical capping, lateral
extrapleural density
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Trauma Ultrasound: FAST
• FAST includes pericardial and pleural
spaces evaluation
• Fluid in acute trauma = blood until proven
otherwise
• Straightforward, “Yes/No” answer
• Pericardial evaluation is very important
and should be the first part of all FAST
scans, esp. penetrating trauma
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Pericardial Evaluation
• Presence of pericardial fluid
• Source of blood
– Great vessels
– Heart
– Pericardial vessels
• Tamponade physiology?
– Collapsed right heart chambers: right atrium – sensitive,
right ventricle - specific
– Distended IVC (caval index = 1)
• Key elements of tamponade
– Rate of fluid accumulation
– Effectiveness of compensatory mechanisms
Nypemergency.org
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Detection of Pneumothorax
• Pneumothorax occult on CXR in 29-72%
• EFAST can identify pneumothorax before CXR
• Identify contiguity of visceral and parietal pleura
using simple US signs
– To exclude pneumothorax
– Extended FAST (EFAST)
– Normal = lung sliding (B), seashore sign (M mode)
– Abnormal = loss of lung sliding (B), stratosphere (M),
lung point (B & M)
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Pneumothorax:
A line sign
• Seeing A-line with loss of
lung sliding suspect
pneumothorax
• One B-line can R/O
pneumothorax where
probe is applied
Lung point
• Most specific sign
• At border between
aerated lung and ptx,
there is intermittent
appearance of lung
sliding during inspiration/
expiration
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Detection of Pneumothorax
• Absent lung sliding
– Sensitivity 100%, specificity 78%
• Absent lung sliding + A line sign
– Sensitivity 95%, specificity 94%
• Lung point
– Specificity 100%
• EFAST more sensitive than portable CXR
trauma
Lichtenstein DA et al. Crit Care Med 2005
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Pitfalls of US on Pneumothorax
• “Loss of lung sliding” alone is not specific
for pneumothorax
– Pleural adhesion/thickening
– Atelectasis
– Lobec/pneumonectomy
– One-lung intubation
• Look for “Lung Point”
• Comparison with contralateral lung
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CT in Thoracic Trauma
• Role of CT used to be for R/O thoracic
aortic injury
• Now CT believed to be most accurate for
diagnosis several thoracic trauma
• Yield of CT is higher when done after an
abnormal initial CXR or performed
selectively based on clinical criteria
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CT Technique
• Helical mode
• Thinnest collimation possible and reformatted
to 2-2.5 mm for viewing
• 120 kV
• Automatic tube current modulation
• No plain scan
• Late arterial phase + delays at site of
vascular injuries
• Routine coronal and sagittal reformations
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What Else We Are Looking For?
• ABC’s of Jud W. Gurney (chestx-ray.com)
– Systematic evaluation of blunt thoracic trauma
– A, B, C, D, E, F, G, H, I
• Missed diagnosis
– 4% died within 24 hours
– 30% missed interpreted
• Aortic injury
• Diaphragmatic trauma
• Flail chest
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Aortic Injury (TAI)
• 16% MVA fatalities
• 85-90% mortality prior to reaching hospital
– Survivors
• 30% died within 6 hours
• 50% died within 24 hours
• 72% died within 8 days
• 90% died within 4 months
uvahealth.com
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Aortic Injury (TAI)
CXR Signs of TAI
Mediastinal widening (>8 cm at aortic
arch level, or by visual assessment)
Loss of AP window, descending T-aorta
Tracheal shift to the right of T4 SP
NG tube displacement to the right
Widened paraspinal or right paratracheal
stripes
Left apical pleural cap sign
Normal (10-15%)
For CXR: PPV 10%, NPV 98%
but TAI is life-threatening, keep low threshold for CT
X-ray signs are related to
mediastinal hematoma
>8 cm
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Aortic Injury (TAI)
• Indirect CT signs
– Periaortic hematoma
• Direct CT signs
– Pseudoaneurysm
– Intimal flap
– Intimal irregularity
– Pseudocoarctation
– Extravasation
• Term “traumatic dissection” is discouraged (confusing
with aortic dissection related to hypertension)
Pseudoaneurysm and periaortic hematoma
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Aortic Injury (TAI)
• Periaortic mediastinal hematoma
– Small veins in area of injury or vasa vasorum
– Does not arise directly from aorta tear
– Usually adjacent to aoric arch and prox descending
aorta, but may tracts down descending aorta to
diaphragm (retrocrural)
Retrocrural hematoma seen on
abdominal CT without clear
etiology (ie, spine fracture)
should raise a concern for TAI
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Aortic Injury (TAI)
• Transesophageal echocardiography (TEE)
– Heart (for contusion) and t-aorta
– More invasive than CT and usu requires sedation
– Blind spots: arch, arch vessels, distal ascending aorta
– May be used intraoperatively
• Catheter aortography
– Prior gold standard, now reserved for selected cases
and for endovascular Rx
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(Tracheo)Bronchial Injury
• Traumatic pneumomediastinum: must exclude
– Airways injuries (larynx, tracheobronchus)
– Esophageal injuries
• Bronchoscopy gold
standard
• However, most are benign
– Extension of pneumothorax
through pleural tear
– Pulmonary alveolar rupture
“Macklin effect”
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Cord Injury
• 25% spine fractures
• 90% neurologic injury
• Most common site = T9-11
– Critical zone
– Transition of facet joint orientation: T facets face
inward, L facets face outward
• Difficult assessment on trauma CXR
– Portable technique
– Rule of 2’s
Thoracic spine fractures often
causes spinal cord injury
because cord is large in
relation to the canal
Image from superhuman.net.au
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• On AP view, look at pedicles and spinous
processes
• Everything no more than 2 mm from one level to
the next
– Interspinous space
– Interpedicular distance
• Elevated paravertebral stripes
– Also sign of TAI
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Flail Chest
Rib fractures
• Most common findings after blunt
chest trauma
• CXR sensitivity 18-50%
• Most common = rib 4-9
– Rib 1-3 neurovascular injury
– Rib 9-12 liver, spleen, kidney
• Absence of fracture lines:
– In adults >65 years may warrant rib series.
– In children, it does not mean mild injuries because of
pliable ribs