Ultrasound

Airway Ultrasound

Rapid Review

  • Indications
    • Confirmation of ET tube placement
    • Identifying landmarks prior to cricothyroidotomy
  • Common Findings
    • Confirming ET tube placement
      • One air-mucosal interface w/ comet-tail artifact and posterior shadowing indicates successful tracheal intubation.
      • Two air-mucosal interfaces (“Double tract sign”) indicates esophageal intubation
    • Cricothyrotomy landmarks
      • Longitudinal = dark, anechoic “string of pearls” represent tracheal rings
      • Transverse = “TACA method” (Thyroid, Air, Cricoid, Air). Thyroid will appear as a V-shape. Air will appear as a hyperechoic white A-line. The Cricoid appears as a hypoechoic round arch-shaped structure.

Pearls

  • Visualization of anatomic structures under ultrasound is best when the patient is in a “sniffing” position.
  • In the longitudinal view, the largest “pearl” along the “string of pearls” represents the cricoid cartilage. 
Video Credit: InterAnest

Abdominal Aorta Ultrasound

Rapid Review

  • Indications
    • Suspected AAA (abdominal pain, hypotension, pulsatile mass)
  • Interpretation
    • Begin in the epigastric area. The abdominal aorta should taper as you track further distally. Be suspicious if the aorta begins to dilate. 
    • AAA is diagnosed when the diameter > 3 cm

Pearls

  • Be careful not to misinterpret the abdominal aorta with the inferior vena cava (IVC). The IVC will be compressible and non-pulsatile, usually to the right of the abdominal aorta.
  • Ultrasound has high sensitivity for ruling in AAA rupture, but cannot reliably rule out the disease as most ruptures are retroperitoneal and unable to be reliably viewed on ultrasound.
Video Credit: EMRAP
Video Credit: EMRAP

Biliary Ultrasound

Rapid Review

Pearls

Video Credit: AMBOSS

Cardiac Ultrasound

Rapid Review

  • Indications
    • Chest pain/Palpitations
    • Significant EKG changes
    • Shortness of breath
    • Hypotension
    • New heart murmurs
    • Cardiac arrest
    • Dizziness
  • Common Findings/Interpretation
    • Regional wall motion abnormality
      • Suggests ischemic heart disease
    • Poor squeeze
      • Decompensated HF
    • Hyperdynamic Squeeze
      • Sepsis, Pneumonia
    • McConnell’s Sign
      • Acute PE
    • D Sign
      • Acute PE
    • RA Collapse/RV Collapse
      • Cardiac tamponade
    • Pericardial effusion
      • Best found with parasternal long-axis and subcostal four-chamber view

Pearls

  • Unlike most standard applications, we want the probe marker on the RIGHT side of the screen for cardiac ultrasound.
  • If the supine position is not getting adequate images, resposition the patient into the left lateral decubitus position. This will help bring the heart awy from the sternum.
Video Credit: POCUS Geek

Lung Ultrasound

Rapid Review

  • Indications
    • Shortness of breath
    • Hypoxia
    • Pleuritic chest pain
    • Chest trauma
  • Common findings/interpretation
    • A-lines
      • Normal lung
    • B-Lines
      • Sensitive for pulmonary edema
    • Absence of lung sliding; finding of “lung point”
      • Suggests pneumothorax
    • Shred sign
      • Sign of lung consolidation (pneumonia)

Pearls

  • The “BLUE” (Bed Lung Ultrasound in Emergency) protocol evaluates for 5 major etiologies of respiratory failure (pneumothorax, pneumonia, pulmonary edema, pulmonary embolism, and COPD/asthma). It is 90.5% accurate in identifying a cause for respiratory failure.
  • Both the curvilinear and phased array probe can be used for lung ultrasound, but the depth will need to be decreased. 
Video Credit: EM:RAP

Inferior Vena Cava Ultrasound

Rapid Review

  • Indications
    • Assessment of intravascular volume status during hypotensive states (sepsis, hemorrhage, heart failure, dehydration)
  • Interpretation
    • IVC < 1 cm
      • In the setting of trauma, associated with high likelihood of hemorrhage requiring blood transfusion
    • IVC < 1.5 cm
      • Suggests volume depletion
    • IVC 1.5 – 2.5 cm
      • Normal finding
    • IVC > 2.5 cm
      • Suggests volume overload

Pearls

  • The “Sniff test” is another way to measure the IVC. Having the patient sniff quickly will cause intrathoracic pressure to drop and cause the IVC to collapse. Patients with IVC  > 2.5 cm will usually have no change. Patients with IVC < 1.5 cm will usually have total collapse.
  • Ultrasound evaluation of the IVC is low cost and has the potential to be useful, but due to technical limitations and errors in interpretation, it should not be used in isolation for determining volume status in critical patients.
Video Credit: Clarius Mobile Health

Ocular Ultrasound

Rapid Review

  • Indications
    • Vision loss
    • Symptoms of increased ICP
    • Trauma
  • Common Findings/Interpretation
    • Disruption of globe architecture or anterior chamber collapse
      • Globe rupture
    • Hypoechoic fluid posterior to globe
      • Retrobulbar hematoma
    • “Twinkle” or hyperechoic object
      • Foreign body
    • Posteriorly displaced lens
      • Lens detachment
    • Separation of hyperechoic linear structure from posterior choroid
      • Retinal detachment

Pearls

  • If there is already clinical concern for globe rupture, do NOT perform ultrasound. If you find signs of globe rupture on exam, immediately discontinue to avoid exacerbating the injury.
  • Copious amounts of gel is advised to prevent applying excessive pressure to the eye.
Video Credit: Anna Pickens

Soft Tissue Ultrasound

Rapid Review

  • Indications
    • Suspected foreign bodies
    • Suspected soft tissue infection
  • Common Findings/Interpretation
    • Cobblestoning
      • Suggests cellulitis
    • Hyperechoic ring, hypoechoic circular area, squish sign
      • Suggests abscess
    • Acoustic shadowing (ring down appearance)
      • Wood/splinter foreign body
    • Reverberation
      • Metal foreign body

Pearls

  • Scan unaffected tissue first to establish a baseline for the patient’s normal anatomy.
  • Ultrasound can be used to evaluate extremities inside of a water bath to achieve soft tissue visualization without having to touch the painful affected area.
Video Credit: BC Emergency Medicine Network

Testicular/Scrotal Ultrasound

Rapid Review

  • Indications
    • Evaluation of testicular/scrotal pain
  • Interpretation
    • Testicular torsion
      • “Whirlpool sign”
      • Secondary findings (hydrocele, scrotal wall thickening)
      • Decreased/absent flow in the affected testical, utilizing color doppler
    • Testicular appendage torsion
      • Enlarged, rounded extra-testicular masses, with mixed hyperechoic/heterogeneous texture
      • Absent flow on color doppler
    • Epididymitis
      • Heterogeneous echogenicity
      • Enlargement
      • Secondary findings (hydrocele, scrotal wall thickening)
      • Increased flow in the affected testical,
    • Testicular Rupture
      • Disruption of tunica albuginea
      • Focal/diffuse loss of vascularity (color doppler)
    • Testicular tumors
      • Well-defined, hypoechoic/heterogeneous intratesticular lesion
    • Fournier Gangrene
      • Diffuse subcutaneous tissue thickening. 
      • Bright echogenic foci w/ dirty shadowing and reverberation artifacts (soft tissue gas)

Pearls

  • Start with the unaffected testicle first as a baseline and optimize your settings prior to examining the affected testicle.
  • When performed correctly by the emergency physician, testicular ultrasound has a high sensitivity (95%) and specificity (94%) for testicular torsion. 
Video Credit: 123radiology

Trauma Ultrasound (E-FAST)

Rapid Review

  • Indications
    • Blunt or penetrating trauma
  • Common Findings/Interpretation
    • Absent lung sliding
      • Suggests pneumothorax
    • Anechoic area in pericardial space
      • Suggests pericardial tamponade
    • Anechoic area between liver and kidney
      • Suggests hemorrhage in morrison’s pouch
    • Anechoic area between diaphragm and spleen
      • Suggests hemorrhage
    • Anechoic area between spleen and kidney
      • Suggests hemorrhage
    • Anechoic area between superior and posterior to walls of bladder
      • Suggests hemorrhage

Pearls

  • Not all bleeding will appear anechoic. Clotted blood may have mixed echogenicity under ultrasound. 
  • The original “FAST Scan” only views the abdomen/pelvis. The “eFAST” exam includes the lungs and heart as well.
Video Credit: POCUS Geek