Focused Abdominal Sonography for Trauma Samuel Kingsley Advocate Illinois Masonic Hospital

Abdominal Ultrasonography An important diagnostic modality within the trauma population Originally reported in this context by German and Japanese physicians in the 1970s US implementation and publications began in the 1980s Rozycki (1995) formalized the abdominal assessment describing four windows: RUQ, LUQ, Pelvis, Pericardium Shackford (1996) introduced the acronym FAST

Pros & Cons Benefits: Rapid assessment Non invasive No radiation Requires no drugs/toxins Serial assessments Rapid learning curve Drawbacks: False negative Misses injuries not associated with large extravasation Possible false positives User dependent Skills decay over time

Accuracy FAST exam requires ~200cc of fluid to be positive (reports of 100cc) Sensitivity of FAST 73-88% Specificity of FAST 98-100%

Indications Blunt abdominal trauma Penetrating trauma In unstable patient, can help determine source: peritoneal bleed vs. pericardial effusion vs. BCI In stable patient, presence of fluid helps to determine need for CT imaging Penetrating trauma Unstable patient – no indication to perform FAST; patient should be taken immediately to OR Stable patient – assess for automatic operative indications (stability), trajectory, evisceration, hematemsis, BPR; if negative… A positive FAST will rule in operative intervention a negative FAST does not rule out operative intervention (sensitivity< 50%)

Anatomy

Anatomy

Equipment

Probe Types

Orientation

Probe Types

Probe Types

Orientation

Sonosite M Turbo

Sonosite M Turbo

Sonosite M Turbo

Sonosite M Turbo

Sonosite M Turbo

Sonosite M Turbo

FAST Exam Technique Pelvic Right Upper Quadrant Left Upper Quadrant Cardiac

FAST Exam Pelvis Curvilinear probe Position just above pubic symphysis and aim inferior

Pelvic U/S The bladder will be visualized as a large, hypoechoic sphere Extravesicular fluid (blood) will appear as hypoechoic layering inferior to the bladder

FAST Exam RUQ Curvilinear probe Lateral most aspect of torso just superior to umbilicus Position probe parallel to ribs (~2 o’clock) to minimize shadowing

RUQ Ultrasound

FAST Exam LUQ Curvilinear probe Spleen is much smaller than liver - probe position is HIGHER and MORE POSTERIOR compared to RUQ “Knuckles on the bed”; position probe parallel to rib space (~10 o’clock)

LUQ Ultrasound

FAST Exam Cardiac Curvilinear probe Place probe in subxyphoid window The probe should be almost parallel with the patient; the orientation marker should point in the same direction as the dot on the screen; depth should be 19-23cm

Subxyphoid

IVC assessment Once the subxyphoid view is established, the IVC can be assessed by rotating the probe 90° so the marker is pointing upwards IVC diameter (3cm from RA) <1cm correlates with hypovolemia; >2cm correlates with euvolemia or hypervolemia Collapse is important as well

IVC assessment

Questions?