- Prioritize: Do primary survey of ATLS first (ABCDE)
- FAST exam follows ABCDE to assess “C” looking for free fluid
- Sensitivity of 42% and specificity of ≥98%
- As little as 100 mL of free fluid can be seen, though >500 mL is needed for the common user
- If blunt trauma start with RUQ view first
- In penetrating start with cardiac views first to rule out tamponade
- Serial exams extremely helpful
- FAST is useful in patients with blunt or penetrating traumatic injury
- Enables trauma bay decision:
- Stable patient with traumatic mechanism of injury + negative FAST → observation
- Stable patient with traumatic mechanism of injury + positive FAST → CT
- Unstable patient with traumatic mechanism of injury + negative FAST → repeat FAST or CT
- Unstable patient with traumatic mechanism of injury + positive FAST → laparotomy
- Select probe
- Curvilinear/large convex probe is ideal but phased array probe may be substituted
- Sequence can vary depending on mechanism of injury
- Include cardiac, RUQ, pelvic, and LUQ views
- Visualize the heart and pericardium using the liver as an acoustic window
- Scan anterior to posterior through the heart
- Coronal view over the right flank
- Visualize the interface between the liver and kidney
- Scan anterior to posterior identifying Morison’s pouch and the superior and inferior pole of the kidney
- Sagittal view just superior to the pubic symphysis
- Identify the bladder
- Scan medial to lateral to identify fluid posterior and superior to the bladder
- Coronal view over the left flank
- Identify the space between the spleen and diaphragm and the spleen and the kidney
- Scan through anterior to posterior of the splenodiaphragmatic space and superior and inferior pole of the kidney
- Positive FAST will have one of the following:
- Anechoic area within the pericardial space
- Anechoic areas between the liver and kidney
- Anechoic areas between the diaphragm and spleen
- Anechoic areas between the spleen and kidney
- Anechoic areas between superior and posterior to the posterior wall of the bladder
Pearls and Pitfalls
- Morison’s pouch
- Scans must scan through the inferior poles of the kidneys as this can contain small quantities of fluid
- Serial exam may be needed
- Negative exam does not rule out intraabdominal injuries
- Retroperitoneal hemorrhage not easily identified
- Those with delayed presentation may have clotted and not demonstrate completely anechoic fluid collections
A bedside FAST ultrasound was conducted to assess for free fluid with clinical indication of trauma. Cardiac, RUQ, pelvic, and LUQ views were adequately obtained. There was no free fluid identified.
A bedside FAST ultrasound was conducted to assess for free fluid with clinical indication of trauma. Cardiac, RUQ, pelvic, and LUQ views were adequately obtained. There was free fluid identified in the RUQ suggesting intraabdominal hemorrhage.
- Sonoguide: Ultrasound in Trauma – The FAST Exam
- EMCrit: Podcast 102 – Don’t Half-Ass your FAST!
- eFAST : extended Focused Assessment with Sonography in Trauma
- EFAST exam
- Cardiac ultrasound
- IVC ultrasound
- Ultrasound: Lungs
- Ultrasound (Main)
- Renal ultrasound
- Bladder ultrasound
- Abdominal Trauma
- Ultrasound: In Shock and Hypotension
- Natarajan B, Gupta PK, Cemaj S, et al. FAST scan: Is it worth doing in hemodynamically stable blunt trauma patients? Surgery. 2010;148(4):695-700.
- Miller MT, Pasquale MD, Bromberg WJ, et al. Not so FAST. J Trauma. 2003; 54(1):52-59.
- Goldberg GG. Evaluation of ascites by ultrasound. Radiology. 1970; 96(15):217–221.
- Von Kuenssberg Jehle D, Stiller G, Wagner D. Sensitivity in detecting free intraperitoneal fluid with the pelvic views of the FAST exam. Am J Emerg Med. 2003 Oct;21(6):476-478.
- McKenney KL, McKenney MG, Cohn SM, et al. Hemoperitoneum score helps determine need for therapeutic laparotomy. J Trauma 2001; 50(4):650–654.