Bedside Aorta Ultrasonography

imagesClinical suspicion of abdominal aortic aneurysm (AAA)


   imagesUnexplained abdominal, back, or flank pain, particularly in the older patient


   imagesUnexplained hypotension


   imagesSyncope in the setting of abdominal pain


   imagesPalpable and/or pulsatile abdominal mass


CONTRAINDICATIONS



imagesNone: No contrast or radiation involved


LANDMARKS



imagesThe proximal aorta is located in the subxiphoid area


imagesThe aorta bifurcates into the iliac vessels at the level of the umbilicus


imagesOn the ultrasound display (FIGURE 12.1), first locate the vertebral body. The transverse proximal aorta is located above (anterior to) the vertebral body, to the right of the inferior vena cava (IVC), and below (posterior to) the superior mesenteric artery


TECHNIQUE



imagesApply ultrasond gel on the patient’s abdomen, from the xiphoid process to just distal to the umbilicus


imagesUsing a standard 3.5- to 5.0-MHz probe with the selection marker to the patient’s right, identify the proximal aorta in the epigastric area (FIGURE 12.2)


imagesOnce the aorta is identified, scan the entire length of the vessel to the iliac bifurcation at the umbilicus



images


FIGURE 12.1 Transverse proximal aorta anatomy. IVC, inferior vena cava; SMA, superior mesenteric artery. (Courtesy of David Riley, MD.)



images


FIGURE 12.2 Ultrasound technique.


imagesMeasure the vessel diameter from outer wall to outer wall to avoid underestimation


imagesVessel measurement in the following views permits adequate screening for AAA (FIGURE 12.3):


   imagesTransverse proximal aorta


   imagesTransverse middle aorta


   imagesTransverse distal aorta


   imagesTransverse view of iliac arteries at the bifurcation


   imagesLongitudinal aorta


imagesIf an aneurysm is detected (TABLE 12.1), its relation to the renal arteries and aortic bifurcation should be documented if possible (i.e., proximal, distal)


imagesIf the aorta is not readily identified, try the following techniques:


   imagesApply gentle downward pressure with the probe to displace bowel gas


   imagesIncrease the depth of penetration on the ultrasound display


   imagesReimaging after several minutes may permit improved visualization as intestinal peristalsis displaces bowel


   imagesPlace the patient in the right or left lateral decubitus position


   imagesApproach para-midline by directing the probe toward the spine to avoid bowel gas


   imagesImage coronally through the liver


   imagesImage inferiorly to the umbilicus and direct the probe cephalad


COMPLICATIONS



imagesDelay in definitive surgical treatment in order to perform study. Computed tomography (CT) evaluation typically poses a greater time delay.



images


FIGURE 12.3 A: Longitudinal aorta. B: Transverse image of the common iliac bifurcation. (Images courtesy of David Riley, MD.)

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Aug 9, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Bedside Aorta Ultrasonography
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