The FAST scan — views and limitations

The four views of the FAST scan:

1. The right upper quadrant (the Morrison pouch) — the hepatorenal recess, the most dependent area in the supine patient and the most sensitive view for the free fluid.
2. The left upper quadrant (the splenorenal recess) — the free fluid around the spleen.
3. The subxiphoid (the pericardial view) — the pericardial effusion (the tamponade).
4. The suprapubic (the pouch of Douglas) — the free fluid in the pelvis. The limitations: the FAST detects the free fluid, not the organ injury — a splenic laceration without the free fluid is missed. The FAST does not detect the retroperitoneal injury (the kidney, the duodenum, the pancreas). The FAST does not detect the hollow viscus injury (which may produce only the minimal fluid initially). The FAST is unreliable in the obese patient and the patient with the subcutaneous emphysema. A negative FAST does not exclude the abdominal injury in the significant mechanism.^[1]