The FAST (focused assessment with sonography for trauma) exam is a common application of ultrasound in trauma to identify intraabdominal and intrathoracic injury. The right upper quadrant view is the most sensitive. How important is the left upper quadrant view? There are really three places where free fluid can potentially collect in the left upper quadrant - the subphrenic space (between spleen and diaphragm), splenorenal recess (between spleen and kidney), and left paracolic gutter (inferior to spleen).
How often is the left upper quadrant positive without free fluid seen in the other two intraabdominal spaces of the FAST exam (bladder, RUQ)?
What is the predominant location of the free fluid in the left upper quadrant?
FAST exams performed on emergency department patients in two sites over 2 years
Inclusion: >18 yo + trauma + positive FAST results in abdomen
Exclusion: hx of ascites, peritoneal dialysis, FAST performed for something other than trauma
All EM attending physicians at the sites were credentialed to perform FAST exams.
FAST was performed by residents and attendings of variable experience.
No specific training for the study (since retrospective).
Retrospective review using ultrasound image archival system, searching for “positive FAST” and “false negative”
All exams reviewed by study investigator and expert to confirm free fluid in abdomen, then to determine location(s)
Also reviewed for adequacy of exam
All patients had FAST exam performed.
FAST (focused assessment with sonography in trauma)
Curvilinear or Phased Array Probe
Right upper quadrant
Left upper quadrant - anterior posterior fanning in each view
c) Paracolic gutter
The Three Places LUQ can be positive
Subphrenic - between diaphragm and spleen. Traditionally taught as most sensitive.
Splenorenal - between spleen and left kidney. Traditionally taught as low yield.
Left paracolic gutter - inferior to spleen. Traditionally neglected.
405 FASTs reviewed, 100 included
32 had free fluid in LUQ
6 (or 6% if you're a math whiz) had isolated LUQ free fluid → 86% (5 of 6) had isolated splenic injury, the other had renal lac, liver lac, and IVC injury
4 in paracolic gutter
1 in subphrenic space
1 in multiple LUQ views
0 in splenorenal
51% of FAST exams had inadequate LUQ views
89% of those inadequate in LUQ were due to poor or absent subphrenic views
Very small sample size
1. In this study, LUQ was the only positive part of the FAST 6% of the time.
2. Although small sample, most common space for LUQ free fluid was left paracolic gutter.