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!
REFERENCES
Williams et al. The FAST and E-FAST in 2013: Trauma ultrasonography – Overview, practical techniques, controversies, and new frontiers. Crit Care Clin. 2014. 30:119-150. PMID: 24295843.
Melniker et al. Randomized controlled clinical trial of point-of-care, limited ultrasonography for trauma in the emergency department: The first sonography outcomes assessment program trial. Ann Emerg Med. 2006 48(3):227-35. PMID: 16934640.
Stengel D, Bauwens K, Rademacher G, et al. Association between compliance with methodological standards of diagnostic research and reported test accuracy: meta-analysis of focused assessment of US for trauma. Radiology 2005; 236(1):102–11. PMID: 15983072.
Brooks et al. Emergency ultrasound in the acute assessment of haemothorax. Emerg Med J. 2004. 21(10):44-6. PMID: 14734374.
Blaivas et al. A prospective comparison of supine chest radiography and bedside ultrasound for the diagnosis of traumatic pneumothorax. Acad Emerg Med. 2005. 12(9):844-9. PMID: 16141018.
Tsui et al. Focused abdominal sonography for trauma in the emergency department for blunt abdominal trauma. Int J Emerg Med. 2008. 1:183-187. PMID: 19384513.
Chiu et al. Abdominal injuries without hemoperitoneum: a potential limitation of focused abdominal sonography for trauma (FAST). J Trauma. 1997. 42(4):617-23. PMID: 9137247.
*Note: All identifying information and certain aspects of the case have been changed to maintain patient confidentiality and protected health information (PHI).
ALiEM Copyedit
October 7, 2014
Nice post, Drs. Shih and Hall. After some minor copyediting changes, I have a few comments/notes:
1. You mostly mention “E-FAST” and then sometimes interchange it with FAST later in the article, but aren’t you really talking about the FAST primarily? It was my impressing that E-Fast includes the pneumothorax views with the linear probe. To avoid confusion, should we just be saying FAST? I think it’s fine to discuss the E-FAST at the end as you have.
[AUTHOR RESPONSE: Thanks for the comments, Michelle! I have made the changes you suggested. Agreed that more consistent use of the term FAST is less confusing.]
2. Nice references.
3. Excellent QA section discussing ultrasound imaging technique and troubleshooting tips. Very practical tips.
Michelle Lin, MD, ALiEM Editor in Chief; Associate Professor of Emergency Medicine, UC San Francisco
Pre-Publication Critique
October 9, 2014
Hey guys. Great case. Here are my comments:
1. You might consider looping the clips for each upper quadrant so that we get a better look at what’s happening. Currently you have both RUQ and LUQ in only a 5 second clip and I found myself hitting replay multiple times because the RUQ disappeared so fast. I’m also not sure that the RUQ is actually negative. At the very beginning of the clip it looks like there may be fluid around the liver tip in the RUQ. If you press play, then pause and move the cursor back to 0:00 seconds you might see what I think I see. It might just be rib shadow, but its very hard to tell, especially with the clip being so truncated. Either way it beautifully demonstrates your point in the QA section about adequacy of views and how to deal with rib shadows. With a mechanism of injury like this I would move my probe to the anterior axillary line to get that shadow out of the way and really see the liver tip. Again, you wrote about this exact situation, but your clip really demonstrates that very problem and you might draw people’s attention to that more directly.
[AUTHOR RESPONSE: Unfortunately, the clips are posted as they were obtained, and are actually that short. I had initially thought about making the clips into a gif, but I like the fact that the video can be paused and scrubbed to get a better look at subtleties. Regarding the RUQ view, I think it is probably negative, based on what I could see on the original clips in QPath. However I do see what you are referring to.]
2. In the images provided the LUQ view does not really reveal the hemi-diaphragm and the tip of the spleen. You aptly pointed out the value of seeing these structures in your discussion, but it might help to point out that these images don’t quite show that anatomy.
[AUTHOR RESPONSE: Good point; I've added commentary on the LUQ view.]
3. I might cut the parentheses with the “aka abdominal” and “aka cardiac” nomenclature. Its a semantic point, but as this is an educational post you may want to emphasize use of the proper names (curvilinear, phased array, and endocavitary) and de-emphasize the misnomers (cardiac, abdominal, and vaginal).
[AUTHOR RESPONSE: I had included the "abdominal" and "cardiac" nomenclature in hopes that it would help those who aren't aware of their proper names to know which probe I'm referring to, and so that the proper name could be learned.]
You guys rock, and I’m jealous of your long, muscular torsos too. Keep up the good work!
Drake Coffey, MD, Assistant Professor, Ultrasound Faculty, Department of Emergency Medicine, UT Health Science Center at San Antonio
Expert Peer Review
October 12, 2014
Great case with excellent imaging.
1) Like the fact that the imaging is not perfect and obvious. The subtle fluid stripe demonstrates the importance of scanning though the the inferior poles of the liver and spleen (respectively) when calling the FAST examination negative for intraperitoneal fluid.
[AUTHOR RESPONSE: Agreed, the ultrasound clips are far from perfect, but are representative of "real-world" clips obtained in the heat of the moment in a stressful situation. Hopefully the "Image Quality Assurance" section provides good constructive feedback and tips on improving the images.]
2) Placing the patient in trendelenberg position could also theoretically improve the sensitivity of the FAST examination.
[AUTHOR RESPONSE: This is a great tip!]
3) For novice providers who are learning to scan, I tell them to tilt the probe marker toward the bed to get parallel to the ribs. Most providers are unfamiliar with the orientation of the ribs in the mid-axillary line or posterior axially line, and this little trick is much easier to remember.
[AUTHOR RESPONSE: Also a good tip.. I personally like to use the phased array probe which is easy to maneuver between ribs.]
4) This patient would have definitely received a computerized tomography (CT) examination of his head/c-spine/chest/abdomen just based on mechanism and his injuries. The FAST examination helps the clinician localize the source of bleeding. Simply put, the FAST or EFAST examination in the sick trauma patient is just a “yes/no” for 3 big cavities (heart, chest and abdomen).
[AUTHOR RESPONSE: Agreed, given the mechanism and the fact that he was stable, CT was the next most appropriate step.]
5) Early subtle FAST positive examinations are great, but the EP must remember that this does not mean a direct trip to the OR in ALL cases. Aggressive resuscitation with an experienced trauma team may mean further imaging before the OR (as in this case). In a non trauma center, the goal of the ED physician would be to perform as many corrective measures as possible, obtain ledge bore intravenous access and get the surgeon there as soon as possible. The subtle positive FAST is a great pick-up that can help prevent the sick patient from getting sicker.
[AUTHOR RESPONSE: I concur!]
Arun Nagdev, MD, Director, Emergency Ultrasound, Alameda Health System, Highland General Hospital, Assistant Clinical Professor, UCSF School of Medicine
Author information
Jeffrey Shih, MD
Emergency Ultrasound Fellow
Instructor in Emergency Medicine
Yale University School of Medicine
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