Case 62: Undifferentiated Hypotension in the setting of Atrial Fibrillation with Rapid Ventricular Response

Lucia Hong, Elaine Yu

A 70-year-old male with a history of cirrhosis, COPD, HTN, T2DM, and large abdominal wall hernia who presented after being found down in his home by a neighbor. Upon arrival, the patient was hypotensive with systolic blood pressures in the 70s and in atrial fibrillation with RVR with heart rates in the 170s. He received 500mL intravenous fluids prior to arrival and was transported on supplemental oxygen. The patient was altered and unable to provide history.

On physical examination, the patient appeared acutely ill and minimally responsive. Mucous membranes were dry. Cardiovascular examination demonstrated tachycardia with an irregular rhythm. Lung examination revealed bilateral breath sounds without focal wheezes or stridor. The abdomen was distended with generalized tenderness and a large non-reducible abdominal wall hernia. Extremities were warm and perfused without significant peripheral edema. Neurologic examination demonstrated altered mental status with intermittent command following and spontaneous movement of all extremities.

Synchronized cardioversion was performed following sedation with fentanyl and midazolam, which resulted in sinus tachycardia with improvement in heart rate and blood pressure.

Vital Signs: BP: 94/62 | HR: 102 | RR: 25 | Temp: 100 °F| SpO₂: 99% on 5L O2

Following cardioversion, RUSH was performed with findings of a small pericardial effusion, a plethoric inferior vena cava with minimal respiratory variation, and abnormal right ventricular wall motion with apparent right ventricular enlargement (Figure 1).

Additionally, intra-abdominal free fluid concerning for ascites was also seen (Figure 2). These findings prompted further evaluation of cardiogenic, obstructive, and distributive shock.

**Figure 1.** Apical 4-chamber view showing right ventricular enlargement with wall motion abnormality characterized as hypokinesia of the right ventricular free wall and contraction at the apex.¹

**Figure 2.** Abdominal ultrasound showing large ascites in the left lower quadrant.²

Labs: WBC 13.3, Hgb 6.9, lactate 2.1, troponin 192 -> 189, D-dimer 26,069

Imaging

CTA PE: No definite pulmonary embolism. Mild volume overload, probably cardiogenic.

CT Abdomen/Pelvis with contrast: 4.7 cm left anterior bladder wall abscess. Large volume ascites.

Discussion

Undifferentiated hypotension in the emergency department presents a diagnostic challenge, particularly in patients with multiple comorbidities and competing etiologies of shock. Rapid Ultrasound in Shock and Hypotension (RUSH) examination has emerged as a critical bedside tool allowing evaluation of physiologic contributors to shock prior to definitive diagnostic testing. The RUSH protocol integrates focused cardiac, vascular, pulmonary, and abdominal ultrasound assessment to assess hypovolemic, distributive, cardiogenic, or obstructive etiologies.³ Incorporation of early bedside ultrasound has been shown to alter the presumed category of shock in up to 50% of patients presenting with nontraumatic hypotension.⁴ RUSH is associated with faster diagnostic clarification and earlier targeted therapy in critically ill emergency department patients.⁵ The utilization of POCUS has demonstrated high specificity for detecting right ventricular strain patterns associated with obstructive shock states.⁶ Furthermore, POCUS can improve evaluation of volume status and reduce potentially harmful fluid overload in critically ill patients.⁷

In this case, the patient presented with hypotension, altered mental status, and atrial fibrillation with RVR. Multiple or mixed shock etiologies were plausible, including septic shock from intra-abdominal infection, cardiogenic shock related to arrhythmia or myocardial injury, and obstructive shock with pulmonary embolism. Additionally, hypovolemia was also considered given an initial Hgb 6.9. Identification of right ventricular wall abnormalities increased clinical suspicion for obstructive pathology, and a subsequent D-dimer was noted to be significantly elevated. CTA PE was completed that ruled out pulmonary embolism and demonstrated volume overload from a likely cardiogenic cause. Further CT images identified a bladder abscess as a source of sepsis. Additionally, RUSH examination findings contributed to cautious fluid administration and prompted consideration of alternative shock mechanisms.

This case highlights how POCUS guides subsequent decision-making. As emphasized in current American College of Emergency Physicians guidelines, POCUS serves as an extension of the physical examination and plays an increasingly central role in the early evaluation of critically ill patients in the emergency department.⁸

References

1. Kansara T, Quesada F, Park H, Ghosh K, Saeed M. McConnell’s Sign Still Holds Its Value: A Lesson Learned From Two Cases. Cureus. 2019;11(11):e6240. doi:10.7759/cureus.6240

2. Zuidewind P. Cirrhosis and portal hypertension. Case study, Radiopaedia.org. Published June 21, 2020. https://radiopaedia.org/cases/cirrhosis-and-portal-hypertension-1

3. Perera P, Mailhot T, Riley D, Mandavia D. The RUSH exam: Rapid ultrasound in shock in the evaluation of the critically ill. Emerg Med Clin North Am. 2010;28(1):29–56.

4. Jones AE, Tayal VS, Sullivan DM, Kline JA. Randomized, controlled trial of immediate versus delayed goal-directed ultrasound to identify the cause of nontraumatic hypotension in emergency department patients. Crit Care Med. 2004;32(8):1703–1708.

5. Atkinson PRT, Milne J, Diegelmann L, et al. Does point-of-care ultrasonography improve clinical outcomes in emergency department patients with undifferentiated hypotension? A systematic review and meta-analysis. Resuscitation. 2018;127:1–9.

6. Nazerian P, Vanni S, Volpicelli G, et al. Accuracy of point-of-care multiorgan ultrasonography for the diagnosis of pulmonary embolism. Chest. 2014;145(5):950–957.

7. Marik PE, Monnet X, Teboul JL. Hemodynamic Parameters to Guide Fluid Therapy. Ann Intensive Care. 2011;1:1.

8. American College of Emergency Physicians. Emergency Ultrasound Guidelines. Ann Emerg Med. 2017;69(5):e27–e54.

July 28, 2025July 28, 2025

Case 52: The Role of FAST in Penetrating Thoracoabdominal Injury

Brandon Woo, Elaine Yu

A 28 year old male with unknown past medical history presented to the emergency department with a single gunshot wound sustained to the anterior chest just prior to arrival. He was brought in by family members who reported a witnessed traumatic gunshot wound to the chest by an unreported individual. The patient complained of trouble breathing and was severely agitated in the setting of pain. He required 75 mg IV ketamine for moderate sedation while obtaining vital signs, ultrasound, and intravenous access. The team prepared for urgent intubation in the setting of possible respiratory decompensation and activated massive transfusion protocol.

On physical exam, the patient was in acute distress and diaphoretic, reporting trouble breathing but speaking in full sentences. He was alert and oriented to person, place, and event. Primary trauma assessment: patent airway, rapid shallow breathing, and capillary refill less than 2 seconds. Secondary survey revealed an approximately 1 cm open wound with active bleeding to the subxiphoid region. There were no step-offs or deformities to the spine and no other obvious signs of trauma externally. There were equal breath sounds, and 2+ pulses were present in the radial and posterior tibialis arteries. The remainder of the exam was unremarkable.

A FAST exam was performed to evaluate for free fluid, hemothorax, or pericardial effusion.

Figure 1: Subxiphoid view

Figure 2: RUQ view

Figure 3: LUQ view

Figure 4: Pelvic view (transverse).

Figure 5: Pelvic view (longitudinal).

Figure 6: Chest X-Ray

Discussion:

The extended Focused Assessment with Sonography for Trauma (eFAST) is a validated rapid, bedside trauma tool, classically validated in hemodynamically unstable patients with blunt trauma where delays in imaging may be fatal. However its use in penetrating trauma is situational. The sensitivity of ultrasound is significantly lower for bowel injury, retroperitoneal bleeding, and intra-abdominal bleeding [1]. This patient was hemodynamically stable, which typically decreases the urgency for bedside ultrasound. However the patient’s agitation, tachypnea, and uncertain injury trajectory of a subxiphoid entry wound made thoracic and abdominal evaluation critical.

The presence of pelvic free fluid (Figures 4,5) and tachycardia with hyperdynamic ventricles (Figure 1) raised concern for intra-abdominal injury and potential hemorrhage. The location of free fluid in a supine trauma patient is influenced by gravity, with the rectovesical or rectouterine pouch being common sites of accumulation [1]. This patient had been upright prior to arrival and was agitated and repositioned multiple times, raising the possibility that the visualized pelvic fluid was gravitational rather than an isolated pelvic organ injury.

Figure 7: Abdominal X-ray.

Free fluid was visualized only in the suprapubic view, which may be due to localized pelvic injury, supported by the bullet location on KUB (Figure 7), or redistributed by gravity from another source, given that the patient had been upright and repositioned prior to evaluation. The absence of fluid in the right or left upper quadrants does not exclude intra-abdominal hemorrhage, particularly in the setting of penetrating trauma, where eFAST sensitivity varies significantly by region and injury type [1,2]. Retroperitoneal bleeding or bowel injury are often missed with eFAST alone, both possibilities in this case.

A meta analysis of over 24,000 trauma patients demonstrated eFAST sensitivity and specificity, respectively, for intra-abdominal free fluid (74%, 98%), pericardial effusion (91%, 94%), pneumothorax (69%, 99%) [2]. In the suprapubic view, sensitivity ranges from 80 - 90%, with specificity ~ 99%, and detection thresholds as low as 100 - 150 mL [2]. The RUQ view, Morison’s pouch, has a sensitivity 85 - 96% and specificity 98%, but typically requires at least 200 mL of fluid for reliable detection [2]. The LUQ view, splenodiaphragmatic space, demonstrates sensitivity 70 - 85% with specificity 98 - 99% [2]. These ranges reflect variations in body habitus, fluid pooling, and operator dependency. These views are widely taught per guidance of the ACEP Sonoguide [5].

A randomized controlled trial found that while FAST did not reduce mortality, it significantly improved workflow and led to a faster time to diagnosis, fewer CT scans, shorter hospital stays, and lower costs [3]. Additional studies have shown that even when eFAST yields false negative results, outcomes are favorable as long as patient status is closely monitored and reassessed [4]. These statistics demonstrate eFAST’s strength in ruling in injuries when positive, but its limitations in ruling out injuries when negative, especially in penetrating trauma, where sensitivity can range from 28-100% depending on trajectory, organ involved, and injury severity [5].

In this case, eFAST was used as an adjunct to clinical decision making, not a replacement for formal imaging or serial exam. Its findings enabled structured handoff, avoiding unnecessary invasive interventions, and highlighted how point-of-care ultrasound can be safely integrated into trauma workflows even when patients fall outside classical indications. Additional data are needed to clarify how patient position prior to arrival, upright versus supine, affects the sensitivity and specificity of eFAST in trauma assessment, particularly in the evaluation of intra-abdominal free fluid.

References:

Tewari V, et al. The efficiency of focused assessment with sonography for trauma (FAST) vs. CT in penetrating torso trauma. J Emerg Trauma Shock. 2024;17(1):3–9.
Netherton S, Milne WK, Proctor C, et al. Diagnostic accuracy of eFAST in trauma: a systematic review and meta-analysis. Can J Emerg Med. 2019;21(6):727–738.
Stengel D, Bauwens K, Sehouli J, et al. Point-of-care ultrasonography for diagnosing thoracoabdominal injuries: a randomized controlled trial. JAMA. 2017;317(11):1110–1119.
Sierzenski PR, et al. Clinical outcomes after false-negative FAST in hypotensive trauma patients. BMC Emerg Med. 2023;23:45.
American College of Emergency Physicians (ACEP). Trauma Ultrasound (eFAST). Sonoguide. Available at: https://www.acep.org/sonoguide/basic/fast
https://www.bcpocus.ca/organscans/efast/

July 29, 2020May 4, 2021

Caudal Edge of the Liver in the Right Upper Quadrant (RUQ) View Is the Most Sensitive Area for Free Fluid on the FAST Exam

Background

The FAST exam is a useful tool in screening for the presence of intraperitoneal free fluid in the setting of trauma. The utilization of ultrasound provides rapid imaging in the trauma bay that can help guide clinical decision making and the necessity for surgical intervention. The FAST exam is comprised of subxiphoid, right upper quadrant, left upper quadrant, and suprapubic views by ultrasound. Previous research has indicated that the RUQ, specifically the hepato-renal space (Morrison’s pouch), is the preferred area for the detection of free fluid.1,2 However, scarce research into the sub-divisions of each view has been performed.

Caudal Edge of the Liver in the Right Upper Quadrant (RUQ) View Is the Most Sensitive Area for Free Fluid on the FAST Exam

Clinical Question

The aim of this study was to determine what specific sub-divided areas of each FAST view were the most sensitive in the detection of intraperitoneal free fluid.

Methods & Study Design

• Design

This was a retrospective cohort analysis.

• Population

All patients who received a FAST exam at a single Level 1 trauma center over an 18-month period.

• Intervention

The RUQ, LUQ, and suprapubic views of the FAST were each subdivided into three additional sections for analysis. Specifically, the RUQ was divided into the hepato-diaphragmatic space (RUQ1), hepato-renal space (Morrison’s pouch) (RUQ2), and the caudal liver tip (RUQ3). The LUQ was divided into the spleno-diaphragmatic space (LUQ1), the spleno-renal space (LUQ2), and the inferior pole of the kidney (LUQ3). The suprapubic area was divided into the lateral sides of the bladder (SP1), posterior bladder and anterior pelvic organ space (SP2), and posterior uterus (in female subjects) (SP3). The subxiphoid view was excluded as the study was only interested in intraperitoneal free fluid.

• Outcomes

Each sub-quadrant of all positive FAST exams was analyzed for the presence of free fluid.

Results

Of the 1,008 FAST scans included in the study, 48 (4.8%) were positive for free fluid. These findings were either confirmed by CT or intraoperatively.
Of the positive FAST exams, 32 (66.7%) were positive in the RUQ, 17 (35.4%) were positive in the LUQ, and 23 (47.9%) were positive in the suprapubic region.
Of the positive RUQ scans, 30 (93.8%) were positive in RUQ3, 27 (84.4%) in RUQ2, and 5 (15.6%) in RUQ1.
Of LUQ scans, 11 (64.7%) were positive in LUQ1, 10 (58.8%) in LUQ2, and 4 (23.5%) in LUQ3.
In the SP view, 15 (64.7%) were positive in SP1, 9 (58.8%) in SP2, and 7/9 (77.7%) in SP3.
No correlation was found between quadrants.

Strength & Limitations

This was a simple, well done study that provides useful information on the FAST exam. The study featured a relatively small sample size of 48 positive FAST exams. There is a potential that in the time between a FAST exam and further intervention (CT or OR) further bleeding could have occurred, thus lowering the sensitivity of the FAST. The authors struggled to make conclusions regarding the suprapubic view between sexes due to a small sample size of positive SP views.

Authors Conclusion

The caudal tip of the liver (RUQ3) is the most sensitive area for the detection of free fluid on FAST exam.

Our Conclusion

The FAST exam can be an extremely useful tool at the bedside or in the setting of trauma. All areas of the FAST should be properly viewed, with particular emphasis on the caudal tip of the liver. It is important to note that many FAST exams only showed free fluid in one area of one quadrant while showing no free fluid elsewhere, therefore it is important to assess all three areas in every view to increase the sensitivity of the FAST exam.

The Bottom Line

Despite previous emphasis on Morrison’s pouch, the caudal liver tip is a more sensitive indicator of intraperitoneal free fluid and should be properly visualized on every FAST exam.

Authors

This post was written by Oliver Marigold, MS4 at UCSD School of Medicine, Charles Murchison MD and Amir Aminlari MD.

References

Von Kuenssberg Jehle, D., Stiller, G. & Wagner, D. Sensitivity in detecting free intraperitoneal fluid with the pelvic views of the FAST exam. The American Journal of Emergency Medicine 21, 476–478 (2003).
AIUM Practice Guideline for the Performance of the Focused Assessment With Sonography for Trauma (FAST) Examination. Journal of Ultrasound in Medicine 33, 2047–2056 (2014).
Lobo, V. 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. WestJEM 18, 270–280 (2017).

February 19, 2020July 21, 2020

Case # 17: Par for the Course

An 80 year old man presents to a rural emergency room at 3am with abdominal pain. His past medical history is significant for mild hemophilia A. Six hours prior to arrival, he was driving a golf cart when he struck a pole and the steering wheel hit his stomach.

He initially had no symptoms but began to have abdominal pain while trying to sleep. He also became nauseated and vomited once. He eventually called EMS and was brought to the ER. On arrival, his vitals are as follows.

Vitals: T: 90.7, HR: 108, BP: 74/48, RR: 28, SpO2 98 on 4L

He is alert, oriented and his only complaint is abdominal pain. A FAST exam was done. What do you see? What are your next steps?

Answer and Learning Points

Answer

Although the quality of images is lacking due to the urgency of the situation and the patient's body habitus, the first image (RUQ) does not show obvious free fluid. The following images (suprapubic and LUQ) clearly show free fluid in the abdomen.

An emergent evacuation of the patient to a level 1 Trauma service was requested. Patient was transfused with two units of O blood. Due to his history of hemophilia A, the patient was also given factor VIII to 100% repletion. The patient was taken to the OR at the level 1 trauma center where he was found to have a greater omental bleed and was successfully treated with clot evacuation and laceration repair. He was placed on a factor VIII drip postop.

Learning Points

- Per ATLS guidelines, a hypotensive patient with a + FAST and no other signs of bleeding warrants immediate surgical exploration.
- In a 2018 meta-analysis, a positive FAST has a sensitivity of 68% and a specificity of 95%. Therefore a negative FAST does not rule out the disease, but a positive fast in the correct clinical sitting (such as this) does rule in hemoperitoneum(1).
- Hemophiliac patients require factor VIII replacement to 100% in the setting of major trauma, which is typically 50 IU/kg(2).

Author

Feigenbaum, Adam, PA-C. Emergency Medicine Fellow, Naval Medical Center San Diego.

Sukhdeep Singh, MD. Clinical Faculty, UCSD Department of Emergency Medicine. Director of POCUS, El Centro Regional Medical Center.

References

Stengel D et al. Point-of-care ultrasonography for diagnosing thoracoabdominal injuries in patients with blunt trauma. Cochrane Database Syst Rev. 2018. Dec 12;12
Guidelines for Emergency Department Management of Individuals with Hemophilia and Other Bleeding Disorders. https://www.hemophilia.org/Researchers-Healthcare-Providers/Medical-and-Scientific-Advisory-Council-MASAC/MASAC-Recommendations/Guidelines-for-Emergency-Department-Management-of-Individuals-with-Hemophilia-and-Other-Bleeding-Disorders. December 5, 2019

September 18, 2017July 22, 2020

Case # 6: Not Your Average Syncope

A 25 year old female presents to the emergency department with acute abdominal pain and a syncopal episode. She notes a positive home urine pregnancy test 1 week ago. She appears mildly uncomfortable with a tender abdomen. A bedside ultrasound is performed, a clip is shown below. What are the findings of the ultrasound clip and what is your diagnosis?

Vitals: T 98.7 HR 120 BP 95/72 RR 20 O2 98% on RA

Image courtesy of Elizabeth Owen, MD

Answer and Learning Point

Answer

The ultrasound clip demonstrates a large amount of free fluid between the spleen and the diaphragm. There is also a sliver of echogenic material above the capsule of the spleen suggestive of clotted blood. Morison’s pouch (not shown) was also noted to be significantly positive for free fluid. Given the patient’s unstable vitals and the clinical history, this was concerning for a ruptured ectopic pregnancy. OB was consulted immediately and the patient was taken to the OR. The diagnosis of ruptured ectopic pregnancy was confirmed during laparotomy. The patient did well.

While the FAST exam has traditionally been used in trauma, there has been increasing use to diagnose intra-abdominal bleeding as a source of hypotension in medical patients. Specifically with regards to ectopic pregnancy, data has suggested that positive free fluid in Morison’s pouch is highly predictive of operative intervention with a positive likelihood ratio of 112 (Sens 50%, Spec 99.5) [1]. A retrospective study in 2001, looking at emergency medicine physician performed ultrasound, demonstrated that identifying patients with a suspected ectopic pregnancy and free fluid in Morison’s pouch decreased the time to diagnosis and treatment [2].

Learning Points

- All women of childbearing age presenting with abdominal pain and syncope should be presumed to have a ruptured ectopic pregnancy until proven otherwise
- Transabdominal ultrasound to evaluate for free fluid should be utilized by the emergency physician in cases of suspected ruptured ectopic pregnancy to assist with risk stratification and rapid diagnosis
- As in trauma patients, evaluation for free fluid should be performed with the patient supine (or preferably Trendelenburg position as this increases the sensitivity of identifying free fluid in Morison’s pouch [3])
- A curvilinear (preferred) or phased-array probe should be used to evaluate the abdomen for free fluid and it is critical to completely visualize the most inferior portion of Morison's Pouch, including the caudal tip of the liver & inferior renal pole, as this is where free fluid will collect first
- A positive pregnancy test and positive free fluid in Morison’s pouch is essentially diagnostic of a ruptured ectopic pregnancy (though ruptured splenic artery aneurysm should also remain on your differential)

Author

This post was written by Michael Macias, MD, Ultrasound Fellow at UCSD.

References

1. Moore C, Todd WM, O’Brien E. Free Fluid in Morison’s Pouch on Bedside Ultrasound Predicts Need for Operative Intervention in Suspected Ectopic Pregnancy. Acad Emerg Med. 2007; 14(8):755-8.
2. Rodgerson JD, Heegaard WG, Plummer D, Hicks J, Clinton J, Sterner S. Emergency department right upper quadrant ultrasound is associated with a reduced time to diagnosis and treatment of ruptured ectopic pregnancies. Acad Emerg Med. 2001; 8:331–6.
3. Abrams BJ, Sukumvanich P, Seibel R, Moscati R, Jehle D. Ultrasound for the detection of intraperitoneal fluid: the role of Trendelenburg positioning. Am J Emerg Med. 1999;17:(2)117-20.

July 16, 2017July 22, 2020

Does This Adult Patient Have a Blunt Intra-abdominal Injury?

Background

Trauma is the leading cause of death in those younger than 45 years in the United States. Around 80% of injuries are due to blunt trauma with 20% involving penetrating trauma. It is blunt trauma, however, that carries substantial diagnostic challenges due to complex injury patterns and difficult management strategies. This paper sets out to review and summarize the comparisons of different techniques in diagnosis of intra-abdominal injury via physical exam findings, laboratory values, and imaging including bedside ultrasound.

Does This Adult Patient Have a Blunt Intra-abdominal Injury?