35 y/o intoxicated male presents after he fell off a 15 foot cliff onto his chest and stomach, landing on concrete. He complains of chest, abdominal, and back pain. BP 140/80 P 135 RR 22.
Answer: Negative FAST exam, full stomach
This FAST exam demonstrates a large heterogenous fluid collection adjacent to the splenorenal space, but the devil is in the details. This collection is noted to have hyperechoic flecks throughout. Additionally, there is no evidence of fluid between the spleen and diaphram, nor between the spleen and left kidney. There is no evidence of hypoechoic free fluid in Morison’s Pouch or in the pelvi
If a large fluid collection is seen adjacent to the spleen, one would expect to see fluid tracking to the more dependent area above the spleen if it were truly free peritoneal fluid. This potential FAST pitfall has been coined the “gastric fluid” sign.1