Madtown Sono

Pertinent Positives in POCUS: Part 1

Objectives

  1. Part 1: Recognize Pathologic Scans for Aorta, eFAST, Cardiac, and DVT studies

Part 1 (presented by Dana Resop, MD)

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Aorta: Where do most AAA's live?

The majority of abdominal aortic aneurysms (AAAs) are infrarenal (below the renal arteries)

Aorta: What is the technique for correctly obtaining a measurement of the aorta?

The aorta should be measured in the short axis (transverse) view at the proximal, mid, and distal aorta

The aorta should be measured from anterior to posterior. Measure the entire aorta, from outer wall to outer wall

It is best to over-estimate the measurement of the aorta; ensure that you are not measuring only the true lumen of the aorta

Aorta: What is a normal measurement of the aorta?

Less than 3cm (remember: three A’s in ‘AAA’, so <3cm is normal)

We start to be concerned about aortas when they are greater than 5cm

eFAST: What are the findings of a pneumothorax on ultrasound?

Lack of lung sliding (visualization only of the parietal pleura)

On M-mode, this appears as the ‘barcode sign’ or the ‘stratosphere sign’

The lung point can be visualized, which is highly specific for a pneumothorax

eFAST: Name several things that can mimic the appearance of pneumothorax (i.e., no lung sliding) on ultrasound

Five ‘False Positives’ for absent lung sliding

  1. COPD/bullous lung disease (visualization of a bleb)
  2. Pleurodesis
  3. Right mainstem intubation
  4. Severe ARDS
  5. Apnea

eFAST: Where are the places to evaluate for free fluid in the right upper quadrant view?

  1. Morison’s Pouch: between the right kidney and the liver
  2. Inferior tip (caudal) of the liver
  3. Above the diaphragm/liver, evaluating for a possible hemothorax

The inferior (caudal) tip of the liver is the most sensitive area!

eFAST: Where are the places to evaluate for free fluid in the left upper quadrant view?

  1. Splenorenal interface: between the left kidney and the spleen
  2. Paracolic gutter: inferior (caudal) portion of the left kidney
  3. Sub-diaphragmatic space (between the spleen and the diaphragm)
  4. Above the diaphragm/spleen, evaluating for possible hemothorax

Cardiac: Name several findings of reduced ejection fraction on cardiac ultrasound

  1. Poor overall visualized squeeze of the chamber of the left ventricular walls
  2. The actual size of the LV cavity/chamber does not reduce in size by >50%
  3. The anterior tip of the mitral valve does not come in close contact with the interventricular septum

Cardiac: True or False, pericardial effusions will cross lateral to the descending aorta

False!

Pericardial effusions will track anterior to the descending aorta (the descending aorta sits outside of the pericardial sac)

Pleural effusions will track lateral to the descending aorta

Cardiac: Name several sonographic signatures for cardiac tamponade

  1. Presence of a pericardial effusion
  2. Collapse of the right ventricle in diastole (sometimes called the trampoline sign)
  3. Collapse of the right atrial in systole (in apical 4-chamber view, earliest sign)
  4. Fat, non-collapsible IVC

Remember, the size of the effusion does not matter. Small effusions can cause tamponade!

DVT: What are the four optimal views when assessing for a DVT?

  1. The junction of the common femoral vein and saphenous vein
  2. The branch point of the common femoral vein into the femoral vein and deep femoral vein
  3. The mid-thigh (assessing for isolated clots), which is the femoral vein distal to its split point
  4. The popliteal vein (posterior to the knee), which sits on top of the popliteal artery

The popliteal vein is where the majority of DVTs will live!

DVT: Name the proper setup and technique for compression of the deep veins in the leg

  1. Place patient in the ‘frog leg’ position in slight reverse Trendelenburg position
  2. Ensure that your ultrasound machine is set to ‘venous’ settings
  3. Compress hard enough to see the walls of the vein touch without compressing the artery

DVT: Name several 'fakeouts' or 'mimics' of a DVT on ultrasound

  1. Inguinal lymph node
  2. Baker’s Cyst