The Case
Young man in his 20s presents after a high speed MVC.
On HEMS arrival he is unresponsive with an obvious left leg deformity with large bleeding wound.
Prehospital:
VS: HR 89, BP 122/70
Interventions
Intubated
Left leg tourniquet
Pelvic splint
1U pRBC given
In the ED:
Initial VS: HR 183. BP 118/91. RR 25 100% on vent
Primary survey: Intubated, BS clear b/l. Tachycardic, but strong pulses
Secondary survey: Left thigh deformity and scattered abrasions on face and torso.
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Teaching point #1: Nominally the patient is normotensive, however these vital signs are quite concerning.
His shock index (HR/SBP) is 1.55 (183/118). Recall that an SI>1 is concerning for impending hemodynamic instability.
Consider adding pulse pressure (SBP-DPB) to your toolkit. A pulse pressure <40 mm Hg, suggests high vascular resistance. In trauma this is concerning for severe hypovolemia and has been shown to be a strong predictor of active hemorrhage (1), need for massive transfusion, and operative intervention (2).
Our patient has a pulse pressure of 27 (118-91).
Together these vital signs are highly concerning for impending hemorrhagic shock and circulatory collapse.
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Teaching point #2: While the patient’s presentation is concerning for a history of hemorrhage from the thigh, his worsening hemodynamic status suggests alternate source of hemorrhage. The eFAST exam can rapidly rule in intraperitoneal and intrathoracic hemorrhage and is predictive of the need for operative intervention even in normotensive patients (3).
An e-FAST exam was performed and the Right and Left Upper Quadrant Views are shown:
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The beginning of the clip shows an outline of a hypoechoic structure inferior to the liver. This is sometimes mistaken for free fluid, but is actually the gallbladder and indicates that the operator is too anterior. A simple adjustment, by fanning the beam posteriorly reveals substantial fluid in the hepatorenal space (Morrison’s Pouch): a POSITIVE FAST
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The LUQ view can be tricky. Finding the splenorenal space (as done in the first part of this clip) is an important landmark, however free fluid is more likely to collect beneath the diaphragm and the inferior tip of the spleen (4). You can see the operator fanning from the splenorenal space to these important landmarks to reveal a POSITIVE FAST.
Case Conclusion
Initially, the team planned for a whole-body CT scan after the secondary survey. However, soon after the FAST exam was completed, the patient’s blood pressure dropped to 72/29. Massive transfusion was initiated and he was taken to the OR emergently. He was found to have a splenic laceration, small bowel injury, as well as large retroperitoneal hemorrhage. After initial damage control laparotomy, he was taken to the CT scanner, where CTA did not show any ongoing extravasation.
Discussion
This case is a nice illustration of the FAST exam algorithm at work, which was proposed in the mid-90s to help appropriate use of the FAST exam. In this case the patient straddled the “stable” category, and the FAST exam helped the team anticipate the next course of action in a timely fashion.
FAST exam algorithm, from Richards & McGahan, 2017 (5)
Key learning points include:
1) Interpret hemodynamic “stability” with caution. Know signs of impending clinical deterioration: high shock index, narrow pulse pressure, and a positive FAST exam can help predict hemodynamic collapse and will help you be prepared.
2) In the RUQ: if you see the gallbladder, you’re too far anterior.
3) In the LUQ: Look all around the spleen. Don’t be satisfied with a view of the spleenorenal space only.
Resident Shoutout: Dr. Ethan Kimball for the solid fans of the upper quadrants.
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1. Priestley EM, Inaba K, Byerly S, et al. Pulse Pressure as an Early Warning of Hemorrhage in Trauma Patients. J Am Coll Surg Aug 2019;229(2):184-191. https://doi.org10.1016/j.jamcollsurg.2019.03.021.
2. Bankhead-Kendall B, Teixeira P, Roward S, et al. Narrow pulse pressure is independently associated with massive transfusion and emergent surgery in hemodynamically stable trauma patients. Am J Surg Nov 2020;220(5):1319-1322. https://doi.org10.1016/j.amjsurg.2020.06.042.
3. Moylan M, Newgard CD, Ma OJ, Sabbaj A, Rogers T, Douglass R. Association between a positive ED FAST examination and therapeutic laparotomy in normotensive blunt trauma patients. J Emerg Med Oct 2007;33(3):265-71. https://doi.org10.1016/j.jemermed.2007.02.030.
4. Lobo V, Hunter-Behrend M, Cullnan E, et al. Caudal Edge of the Liver in the Right Upper Quadrant (RUQ) View Is the Most Sensitive Area for Free Fluid on the FAST Exam. West J Emerg Med Feb 2017;18(2):270-280. https://doi.org10.5811/westjem.2016.11.30435.
5. Richards JR, McGahan JP. Focused Assessment with Sonography in Trauma (FAST) in 2017: What Radiologists Can Learn. Radiology Apr 2017;283(1):30-48. https://doi.org10.1148/radiol.2017160107.