Using Focused Ultrasound to Catch Trauma’s Hidden Dangers: FAST and the Fatal 

-Case-

A 27-year-old male is brought into the ED after a high-speed motor vehicle collision. He is tachycardic at 120 bpm and hypotensive to 85/50 mmHg. On primary survey, he has normal breath sounds bilaterally, but his abdomen is tender with mild distension. 

As trauma resuscitation continues, you grab the ultrasound probe – time for a FAST exam to rule out life-threatening hemorrhage!

Now, what is the FAST Exam?

The Focused Assessment with Sonography for Trauma (FAST) is a rapid bedside ultrasound used in trauma to identify free fluid in the peritoneal, pericardial, and pleural spaces. It helps detect hemorrhage in unstable trauma patients and guides next steps in management.

The Four FAST Views:

• RUQ (Hepatorenal/Morrison’s Pouch): most sensitive for detecting intra-abdominal free fluid
• LUQ (Splenorenal Recess): looks for fluid between the spleen and kidney
• Pelvic (Suprapubic/Pouch of Douglas): checks for free fluid behind the bladder
• Pericardial (Subxiphoid): identifies pericardial effusion/tamponade

-Interpreting the FAST Exam-

• Positive FAST = free fluid identified → assume hemorrhage
  • If unstable → immediate surgical consult and intervention
  • If stable → further imaging (CT scan)
• Negative FAST but unstable? Consider other sources of shock (neurogenic, hemorrhage not seen on FAST)!

-Limitations of the FAST Exam-

• Cannot identify solid organ injury without associated hemoperitoneum
• Body habitus, bowel gas, and prior surgeries can affect image quality
• False negatives in early bleeding (small-volume hemorrhage may not yet be visible)

-Fast Facts-

• FAST Exam is a first-line tool for trauma evaluation
• Pericardial view detects tamponade, a true surgical emergency
• E-FAST expands utility by assessing for pneumothorax and hemothorax
• Negative FAST ≠ no injury! Always correlate with clinical findings!
• In an unstable trauma patient, FAST findings can be the difference between the OR and further imaging!

The FAST exam is a game-changer for our trauma patients. This rapid, non-invasive bedside tool helps ED providers make critical, life-saving decisions in seconds, so grab the ultrasound and FAST-track your diagnosis!

Want to learn more? Listen to our in-depth podcast about the FAST exam!

Cheers,

Tamir Zitelny, MD