Welcome to another ultrasound-based case, part of the “Ultrasound For The Win!” (#US4TW) Case Series. In this peer-reviewed case series, we focus on real clinical cases where bedside ultrasound changed management or aided in diagnoses. In today’s case, a 30-year-old male is brought in after blunt trauma from a high-speed MVC.
Case Presentation
A 30-year-old male is brought in by EMS after a high-speed MVC where a car crashed into a stationary pole. Two other passengers died in the field. Per the EMS report, the patient was approximately 15 feet (4.6 meters) from the vehicle, which suffered major damage.
The patient is immediately brought into the trauma bay, where he is confused but follows commands. He has an obvious humerus fracture. His GCS is 14, and he is moving all extremities. Other than his depressed mental status, the primary survey was unrevealing.
Vitals
- BP 133/88 mm Hg
- P 132 bpm
- RR 28 respirations/min
- O2 100% saturation on 2L nasal cannula
- T 37.1 C
Differential Diagnosis
- C-spine or other spinal injury
- Hollow viscous (bowel) injury
- Intracranial injury
- Pelvic or other orthopedic injuries
- Pneumothorax
- Solid organ injury
- Thoracic injury
Point-of-Care (POC) Ultrasound
A POC FAST (Focused Assessment with Sonography in Trauma) ultrasound was performed, which showed the following:
Video: Bedside FAST video, which only displays the right upper quadrant (RUQ) and left upper quadrant (LUQ) views.
The RUQ view appears negative for free fluid, however there is a small fluid collection seen in the LUQ.
Image: The LUQ view of the bedside FAST, which is positive for free fluid (blue arrow). (s=spleen, k=kidney)
Ultrasound Image Quality Assurance (QA)
An important aspect of ultrasound is appropriate and optimal image acquisition. The clips, showing only the RUQ and LUQ portions of the FAST, demonstrate appropriate gain and probe orientation. The depth in the clip of the RUQ is optimal, with visualization of not only Morison’s pouch, but also of the paracolic gutter, and above the diaphragm looking for potential hemothorax. Unfortunately, the left hemidiaphragm is not well visualized in the clip. Additionally, the depth on the LUQ could be decreased somewhat in order to maximize the use of the focal zone and improve the image quality.
The curvilinear (aka “abdominal”) probe is being used, and, given its relatively large footprint, several rib shadows can be visualized in the clips. While it isn’t an issue in this case, sometimes rib shadows can obscure areas of interest. This is a common occurrence, and a tip to avoid this is to rotate the probe slightly from the coronal plane to run more parallel to the ribs, positioning the ultrasound beam between the ribs. Another option would be to use the phased array (aka “cardiac”) probe, which has a smaller footprint more conducive to maneuvering between rib spaces and thus limiting the number of rib shadows seen.
A common pitfall of the RUQ view is visualizing only the interface between the liver and kidney (Morison’s pouch); however, it is important to assess the caudal tip of the liver, which is more sensitive for smaller fluid collections as they tend to begin there before tracking into Morison’s pouch.1 Additionally, in the LUQ view, it is important to not only visualize the spleno-renal interface, but also the interface between the diaphragm and the spleen.
Disposition and Case Conclusion
Shortly after the FAST was performed, the patient became hypotensive. Fortunately, he responded to fluids. Since he was hemodynamically stable, the decision was made to proceed to CT scan. CT imaging revealed a shattered spleen with multiple lacerations. Hemoperitoneum was noted around the spleen, extending to the right paracolic gutter and perihepatic region.
The patient was brought to the OR by the trauma surgery team. Intra-operatively, he was noted to have a shattered spleen, as well as a large retroperitoneal hematoma. A splenectomy was performed, and serosal tears were repaired. The patient remained hemodynamically stable in the surgical ICU, and was eventually discharged from the hospital. He is currently at home, and doing well!
This case demonstrates the high utility of a bedside FAST exam for trauma patients who present to the ED. The SOAP trial, a multi-center RCT study by Melniker et al. showed that the FAST exam decreases time to operative care, reduces the number of CT scans ordered, and decreases patient morbidity and hospital length of stay.2
A FAST examination is a quick and non-invasive study that can easily be performed in patients with blunt or penetrating trauma. It is sensitive and specific for the identification of hemoperitoneum in the abdomen and pelvis as well as for pericardial effusion. A meta-analysis of 62 trials, which included more than 18,000 patients, showed a pooled sensitivity of 78.9% and specificity of 99.2%.3
An E-FAST (Extended FAST) includes visualizing for pneumothorax or hemothorax, and has been shown to be more accurate than x-ray in identifying these pathologies.4,5
While the FAST is a useful tool in the evaluation of the trauma patient, physicians must be aware of its strengths as well as its limitations. These limitations include the inability to detect certain types of injuries, such as injury to the bowel or diaphragm, retroperitoneal hemorrhage, and vascular injuries.6 Furthermore, a FAST relies on hemoperitoneum, so solid organ injury without evidence of hemoperitoneum will potentially be missed.7 Thus, if there is a high clinical suspicion of intra-abdominal injuries despite a negative FAST, further studies such as serial FAST exams or CT should be considered in the hemodynamically stable patient.
Take Home Points
- The FAST exam has a sensitivity of 78.9% and high specificity of 99.2%, highlighting that while smaller amounts of free fluid may be missed, if seen, it is highly accurate for intra-abdominal injury.3
- Positive FAST + hemodynamic instability = Operating Room (OR)!
- A point-of-care FAST in the ED in the trauma patient decreases time to definitive operative care, improved resource use (fewer CT studies), and reduces patient morbidity.2
- Limitations of the FAST include: limited detection for certain types of injuries (bowel, retroperitoneal, vascular), and abdominal injury without hemoperitoneum.6,7
Special thanks to Dr. Chris Moore for permission to use the included ultrasound clips and images!
*Note: All identifying information and certain aspects of the case have been changed to maintain patient confidentiality and protected health information (PHI).
Author information
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