Traumatic aortic injury in the exam
Getting a film with traumatic aortic injury in the exam is one of the many exam set-pieces that can be prepared for.
This is one of the cases you should look and not speak for 10 seconds as there will be a lot of findings on the film.
Supine frontal chest radiograph, labelled “trauma series”, with an ET tube well above the carina and a NG tube tip below the hemidiaphragm. There is increased opacification that obscures the aortic knob, that is associated with widening of the mediastinum and there is a left sided apical pleural cap. There is displacement of the NG tube and the trachea to the right. There is mass like filling of the aortopulmonary window that widens the left paraspinal stripe and there is inferior displacement and mild narrowing of the left main bronchus.
There is bilateral consolidation that in the context of trauma is likely to represent contusions. There is a loss of height with a fracture to the T10 vertebral body.
The findings are in keeping with a traumatic aortic transection. I will quickly evaluate the patient to ensure he has a wide bore cannula insitu and is haemodynamically stable. I would ring the referring team and tell them that I am arranging for an urgent CT aortic angiogram and tell them that I will also evaluate the thoracic spine on bony windows. I will ensure that the patient transferred to the CT scanner under full spinal precautions.
The CTA confirms a focal dilation of the aorta at the level of the isthmus with a mediastinal haematoma and bilateral haemothorax. There are bilateral pulmonary contusions and several undisplaced rib fractures but there is no associated pneumothorax. There is a compression fracture of T10 with a 6 mm retropulsed fragment that compresses the thecal sac and causes moderate spinal canal stenosis.
- A clear aortic knob outline has a 72% sensitivity, 47% specificity and 87% negative predictive value
- A mediastinal width of more than 8cm at the level of the aortic arch is considered abnormal and has a 53% sensitivity, 59% specificity and 83% negative predictive value