AAA

Early recognition of abdominal aortic aneurysms (AAA) is a core skill for emergency physicians.  Once ruptured the overall mortality is upwards of 90%.  Classical teaching is that AAA’s present with abdominal or flank pain, pulsatile abdominal mass and hypotension but these signs are present in only 50% of patients.

Ultrasound enables  us to screen patients with abdominal pain or concerning symptoms for an AAA in order to guide further management of investigations. This can easily be done at the patients bedside with minimal training. Aortic ultrasound is highly sensitive for identifying aneurysms however it is poor at detecting rupture unless free fluid is identified in the abdominal cavity. CT angiography is the current gold standard at identifying both aneurysm size and rupture.

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AAA have a male predominance and majority are infra-renal.  An aorta with a diameter > 3cm is defined as aneurysmal.   The majority of aneurysms are infra-renal (>80%).  See the following post from EMDOCS for more information regarding presentation and management AAA.

The following videos outline how to perform the AAA scan along with some images of pathology.

Learning & Accreditation Process

Accreditation of eFAST within the department will involve:

• Completion of online learning module through UTEC (Geelong ED Sign on code = GORUS)
  • Or have completed an accredited course.
• Attend departmental workshop.
• Completion of a logbook of 15 AAA scans which will include 3 positive scans and a comparison to gold standard imaging. At least 50% of the scans must be clinically indicated. Revise ASUM CCPU guidelines & minimum imaging set here
• 2 formative assessments and 1 summative assessment by an ED consultant. Form available here for online completion (Smart phone/Tablet compatible).
• CCPU formative and summative assessment forms are at the end of this document if required.
• Ongoing accreditation requires 15 Aorta scans over a 2yr period.

Minimal Imaging Requirements

• Transverse proximal abdominal aorta
• Transverse distal abdominal aorta
• Longitudinal abdominal aorta
• If aneurysm present then transverse image and longitudinal image at the point of largest diameter.
• All images should have maximal diameter measurement (outer wall to outer wall)

 

Resources

• Read
  • Chapter 3 in Introduction to Bedside Ultrasound (Vol 1)
  • Sonoguide AAA 
• Online lectures:
  • UTEC
  • Emergency Ultrasound Teaching