Episode 15: The Seven Deadly Sins - Common US Mistakes and How to Avoid Them

by Bob Stuntz in ,

As a graduate of 12 years of Catholic school, I learned about (and committed most of) the 7 deadly sins.  I spend much of my time now teaching residents ultrasound, and reviewing their images.  In the 7 major US categories (AAA, Biliary, Cardiac, FAST, OB, Renal, and Vascular Access), I have noticed there are common mistakes most novices make.  So what are these 7 Deadly US Sins, and how can we avoid them?

  1. AAA:  To find the aorta, do not look for the aorta.  I know...mind blown.  The aorta is anterior/anterolateral to the vertebral column, so setting your depth high initially and finding the hyper echoic vertebral body with posterior shadowing will guide you to the aorta so you do not mistake the SMA for the aorta. 
  2. Biliary: Beware the ultimate SIN - stone in the neck.  Pay special attention to the neck of the gallbladder.  Sometimes, you will not even see the stone itself, so heavy anechoic shadowing behind the neck of the GB should clue you in.  And remember, Hartman pouches can be tricky, so do not miss a stone in the neck of a Hartman's pouch either.  
  3. Cardiac: Always evaluate the posterior pericardium.  In the subxiphoid view, this means having enough depth and far gain to get there.  In the parasternal long axis, make sure you see the descending thoracic aorta just posterior to the LA/LV.  Pericardial fluid will be anterior to this, and may split between the heart and aorta, while pleural fluid will be lateral/posterior to the aorta.  
  4. FAST: free fluid should have sharp edges and take the shape of its container.  Fluid that is encapsulated, walled off, or rounded in unlikely free fluid.  In the RUQ, the GB sandwiched in between the liver and kidney may be mistaken for free fluid, while a beverage filled stomach may throw you off in the LUQ.  
  5. OB: always find the midline stripe to make sure what you are seeing is truly in the uterus.  A fair number of ectopic pregnancy may have a pseudo gestational sac in the uterus, so remember a yolk sac is the earliest definitive sign of pregnancy.  And size does not matter, you can have a big ectopic.  
  6. Renal: Not all hydronephrosis is ureterolithiasis with obstruction.  A large AAA may compress the ureter, so remember to look for AAA in at risk patients.  Renal colic is possible misdiagnosis of aortic disasters.  
  7. Vascular access: Remember, the point of doing US guided procedures is to always know where your needle tip is.  The US probe can only see what is directly beneath it.  If you are advancing your needle but what you think is the needle is not moving on the screen, you may be looking at the needle shaft.  Stop moving your needle, and move your probe to find it.  TRV vascular access should be a two handed dynamic technique.  

2008 ACEP US Guidelines

Thank you to everyone for reading and listening.  2013 was fun, and I have some great content planned for you coming up.  As always, let me know if you have any questions/concerns/feedback.  If you like what you hear, please go to iTunes to rate and review me.  Know residents that aren't listening?  Let them know about the blog and podcast.  If you are using a reader, I do have an RSS feed here

Also, for US residents, the In Service exam is coming up in February.  Be sure to check out www.emergencyboardreview.com, @EMBoardReview on Twitter.  Hoping to get most of the content there finished in the next few months, and have a ton there already.  Jon Schonert (@emchatter) has done a great job with this.  

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