Amira Faour Emergency Medicine PGY2 4/3/19 AAA Amira Faour Emergency Medicine PGY2 4/3/19

Background Ruptured AAA 10th leading cause of death in M >50 US Triad seen in 33% ruptured AAA Abdominal pain radiating to back Hypotension Pulsatile abdominal mass Dx via US, CT, MRI

Anatomy Abd aorta continuation of thoracic aorta and begins at the aortic hiatus at the diaphragm Abd aorta T12 → L4 where it divides into the common iliac arteries

AORTA 13CM

-normal aorta→ anechoic, echo-free lumen with bright white echogenic walls -TRANSVERSE just below the xiphoid process -get view of AORTA, IVC, VERTEBRAL BODY

5 sites Proximal Mid Distal R iliac L iliac Outer wall to outer wall Distal (just proximal to aortic bifurcation)

AAA Diameter >3 cm Iliac arteries >1.5 cm Focal dilatation (1.5 times the adjacent aortic segment) Lack of normal tapering dilatation Intraluminal thrombus

THIS PIC HAS INTRALUMINAL THROMBUS -scan from xiphoid process to aortic bifucation (near umbillicus) -note any aneurysmal dilatation or intraluminal thrombus

Sagittal view to look for saccular aneurysms USE LIVER as a window Rotate probe 90 degrees with indicator to pts head

Aortic DISSECTION HYPERECHOIC INTIMAL FLAP

his short (usually less than 1 cm) vessel can often be seen sonographically in the transverse plane, dividing in a “wide Y”. The fork on the patient’s right is the common hepatic artery, heading to the porta hepatis; the fork on the patient’s left, is the splenic artery. This sonographic view is known as the “seagull sign”.

Pearls Transverse measurements may overestimate size of aneurysm if measured obliquely Cylinder tangent effect Measurement in longitudinal plane can underestimate diameter if aorta visualized tangentially or taking measurements of the side of midline

Note: transverse measurements may over-estimate the size of the aneurysm if the measurement is oblique

Pearls False + Increased gain or reverberation artifacts Don't confuse with intraluminal thrombus Consider lateral decubitus of cannot visualize aorta anteriorly Bend knees while supine (decrease tension on rectus muscles) Signs of rupture: Intraperitoneal free fluid, retroperitoneal hematoma, lateral displacement of side where aorta is ruptured Absence of intraperitoneal free fluid does not rule out rupturing AAA CAN LEAK INTO THE RETROPERITONEUM CAN BE CONTAINED BY TAMPONADE AND LOCAL CLOTTING

R MID AXILLARY LINE CAN BE USED AS ACOUSTIC WINDOW

THANK YOU!

References https://www.acep.org/sonoguide/abdominal_aortic_aneurysm.html Sonosupport