FAST Exam

The FAST (Focused Assessment with Sonography for Trauma) exam is a rapid bedside ultrasound exam used to detect free fluid (internal bleeding) in trauma patients.
It assess 4 core areas, while extended FAST (E-FAST) adds lung views to assess for pneumothorax and hemothorax. Originally designed for trauma, it is now also used in non-trauma settings to evaluate unstable patients (ie to determine etiology of shock).

⚠️ Note: Remember that while the FAST exam is valuable, it cannot rule out retroperitoneal bleeding or injuries without free fluid. Always repeat the FAST if the initial scan is negative but clinical suspicion remains high, and consider formal imaging if the patient is stable enough.

Pericardial View (Subxiphoid)

Steps for Image Acquisition:

Probe Placement: Subxiphoid area (just below sternum)
Technique: Centre the heart and fan to visualize all four heart chambers. Fan carefully to assess for fluid

Findings:

Pericardial effusions: Anechoic, typically seeen posteriorly first.
Epicardial fat pads: Seen anteriorly with white stranding, not fully anechoic

Right Upper Quadrant (RUQ) - Morrison's Pouch

Steps for Image Acquisition:

Probe Placement: Mid-axillary line, ~8th–11th ribs
Technique: Visualize the interface between liver and right kidney (Morrison’s pouch), sweeping carefully
- Visualize the entirety and look for fluid at:
  - Morrison’s pouch (hepatorenal recess)
  - Tip of liver
  - Subdiaphragmatic space

Finding: Free fluid appears as anechoic (black) in the recesses

Left Upper Quadrant (LUQ) - Splenorenal View

Steps for Image Acquisition:

Probe Placement: Posterior axillary line, ~9th–11th ribs
Technique: Visualize the interface between the spleen and left kidney (splenorenal recess), sweeping carefully
- Visualize entirety and look for fluid at:
  - Splenorecal recess
  - Under diaphragm

Finding: Free fluid between spleen and kidney or above spleen

Pelvic View

Steps for Image Acquisition:

Probe Placement: Transverse orientation just above the pubic symphysis (low down)
Technique: Identify the blader, fan through it, and look for anechoic fluid around it. Rotate to a longitudinal view and scan carefully posterior to the bladder

Finding: Free fluid collects in the posterior cul-de-sac (space behind bladder)