Pediatric emergency medicine trisk 929
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Aortic injury should be suspected when there are severe deceleration
forces; classic physical examination findings may not be present.
Chest radiography is sensitive for the presence of aortic injury and
should be followed by CT angiography when concerning.
Aggressive resuscitation and immediate surgical intervention are
necessary for patients with aortic or great vessel injuries and signs of
circulatory compromise such as tachycardia, poor perfusion, or
hypotension.
Current Evidence
Life-threatening injuries to the great vessels of the thorax carry a high mortality
rate but are fortunately rare. The aorta is the vessel most commonly involved in
both blunt and penetrating trauma. Rupture of the aorta occurs in approximately
10% to 30% of adults sustaining severe blunt trauma but is much less common in
the pediatric population, affecting less than 1% of all children with blunt thoracic
trauma. Early detection of such injuries is vital for survival, as overall mortality
rate of aortic rupture in children is 75% to 95%, with most deaths occurring at the
scene.
Clinical Considerations
Clinical Recognition
Aortic injuries are most frequently associated with high-energy deceleration
forces, commonly from automobile collisions, causing a shearing stress. The
descending aorta is fixed and the arch is mobile. With deceleration, shearing takes
place at the level of the ligamentum arteriosum, the most superior fixation point
and the most common site of aortic tears in adults and children.
When a great vessel ruptures, massive blood loss may ensue. The body’s
compensatory mechanisms for the blood loss include an increase in both heart
rate and total peripheral vascular resistance. Relying solely on a decrease in
systemic blood pressure to detect hemorrhage in children may be deceiving
because children may lose 25% or more of their total blood volume before their
systemic blood pressure is affected. Children with significant bleeding may have
a normal systolic blood pressure but be tachycardic and poorly perfused with a
prolonged capillary refill time. These findings should trigger aggressive
resuscitation and urgent investigation of the source of hemorrhage prior to the
onset of hypotension.
Triage
Children with known or suspected great vessel injury should be evaluated
immediately, mobilizing the highest level of trauma care available. Preparations
for both radiologic evaluation and surgical intervention should begin as soon as
the injury is suspected, as even the stable patient may deteriorate very rapidly.
Clinical Assessment
Children are usually symptomatic from associated injuries, and great vessel
injuries can easily be missed. Clinical signs may include difference in pulse
between the arms or arms and legs, thoracic ecchymosis, thoracic and back
tenderness, paraplegia, and anuria. In patients with more severe injuries,
hypotension or excessive bleeding from a chest tube may be seen. Patients with
paraplegia and back pain may be initially diagnosed with a spinal cord injury.
Unfortunately, 50% of patients with aortic injuries may have no signs pertaining
directly to that injury.
Management
Early diagnosis is imperative in patients with aortic or other great vessel injuries.
Morbidity and mortality increase threefold if operative intervention is delayed
more than 12 hours. CXR is usually the initial study performed. Findings may
include a widened mediastinum, blurred aortic knob, pleural cap, or tracheal or
nasogastric tube deviation ( Fig. 115.8 ). While a normal CXR has been reported
to have a 98% negative predictive value in excluding thoracic aortic tear,
specificity of an abnormal radiograph is poor and, given sufficient clinical
suspicion, further imaging is required to make the diagnosis. Multidetector CT
angiography has largely replaced echocardiography and aortography as the
imaging modality of choice in diagnosing aortic injury, though its test
characteristics in children are unknown. CT angiography should not be performed
routinely on children with thoracic trauma; its use should be limited to those with
high suspicion for injury to the aorta and great vessels based on clinical
presentation or results of CXR. For the stable patient with an equivocal CT or
who requires further delineation of the injury, aortography may be an appropriate
follow-up study ( Fig. 115.9 ).
Treatment of great vessel injuries varies based on degree and location of injury
and stability of the patient. Therapeutic options include fluid resuscitation and use
of beta blockers in hemodynamically stable patients, blood transfusion, and open
or endovascular repair.
Disposition
All patients with a great vessel injury require admission to intensive care until
either definitive repair of the injury or evidence that the clinical condition has
stabilized and is unlikely to deteriorate.
FIGURE 115.8 This 12-year-old girl was an unrestrained passenger involved in a motor
vehicle accident. The patient was hypotensive at the scene and could not move her legs. In the
emergency department, she had no motor or sensory function to her lower extremities and was
anuric. Chest radiograph showed a widened mediastinum from traumatic rupture of the aorta.
CHEST WALL INJURIES
Goals of Treatment
