A 57 yo male presents to the trauma bay after he was pedestrian struck by a motor vehicle. The patient is s/p needle decompression of the right lung and intubation.  His GCS is 3 on arrival.  The patient went into cardiac arrest in the field and achieved ROSC (return of spontaneous circulation).  Patient went into cardiac arrest again following CT and was prounounced dead after multiple rounds of CPR.  The CT is shown.  What's the diagnosis?  Scroll down for answer.

Answer:  Traumatic aortic dissection / transection with pseudoaneurysm

Epidemiology

• traumatic injury to the great vessels (aorta and brachiocephalic trunk) can occur from blunt or penetrating trauma
• in blunt trauma - usually occurs from high speed deceleration
• consider in situations of sudden decerlation such as fall > 10 feet or MVC with speeds above 30mph
• blunt aortic injuries usually occur from MVC
• 90% die at scene - of the 10% that survive to hospital, half will die in first 24 hours

Pathophysiology

• proximal descending aorta most commonly is injured due to fixation of vessels between the left subclavian artery and the ligamentum arteriosum; the aorta is a mobile vessel and moves forward as the tethered portion decelerates with the chest and shearing forces lead to aortic injury
• ascending aortic injuries are rarely diagnosed because patient's do not survive to diagnosis
• the distal aorta is less frequently injured in blunt trauma; the more distal the injury the more likely the survival

Physical Exam

• close observation of HR and BP: patient may have hypotension, or hypertension in UE and hypotension in LE, or unequal UE BPs
• external signs of chest trauma (ie seatbelt sign, steering wheel bruise, thoracic outlet hematoma), intrascapular murmur, palpable fractures, flail chest
• roughly half will present wiht no external signs of trauma

Diagnosis

• CXR - wide mediastinum; >8cm or physician gestalt; normal mediastinum on xray does not rule out
• CTA chest - study of choice to make diagnosis

Treatment

• consult trauma, vascular / CT surgery
• patients with hemodynamic instability, profound heorrhage from chest tubes, and radiographic evidence of aortic injury should proceed to OR immeditely
• blood pressure and heart rate control are key prior to OR or if patient is to be managed non-operatively due to other circumstances
• avoid large swings in BP whcih leads to increase shearing forces
• use beta blocker (esmolol), sedatives, analgesics, vasodilators (nicardipine) in combination to maintian SBP around 100 (100-120) and HR around 60

reference

Long, B. Koyfman, A. (2020). Cardiac Trauma. In 1368857942 1000909131 J. Dubin (Ed.), Tintinalli's Emergency Medicine: A comprehensive study guide (9th ed., pp. 1881-1887). New York, NY: McGrawl Hill.