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Updated: Apr 11, 2026
Focused Assessment with Sonography for Trauma FAST Exam: Image Acquisition
Published on: September 22, 2023
False-positive focused abdominal sonography in trauma in a hypotensive child: case report
Isabelle Imamedjian1, Robert Baird, Alexander Sasha Dubrovsky
1From the *Faculty of Medicine, McGill University; and †Departments of Pediatric Surgery and ‡Pediatric Emergency Medicine, Montreal Children's Hospital-McGill University Health Center, Montreal, Quebec, Canada.
Insights
A focused abdominal sonography in trauma (FAST) exam can be falsely positive in pediatric patients hours after injury, especially after significant fluid resuscitation causes ascites. Interpretation requires considering timing and clinical factors beyond hemoperitoneum.
Area of Science:
- Emergency Medicine
- Pediatric Surgery
- Diagnostic Imaging
Background:
- Focused abdominal sonography in trauma (FAST) is crucial for evaluating hypotensive trauma patients.
- A positive FAST typically suggests intra-abdominal bleeding (hemoperitoneum).
- Delayed or serial FAST examinations require careful interpretation in evolving clinical scenarios.
Abstract:
We report a case of a false-positive focused abdominal sonography in trauma (FAST) examination in a persistently hypotensive pediatric trauma patient, performed 12 hours after the trauma, suspected to be caused by massive fluid resuscitation leading to ascites. While a positive FAST in a hypotensive trauma patient usually indicates hemoperitoneum, this case illustrates that the timing of the FAST examination relative to the injury, as well as clinical evolution including the volume of fluid resuscitation, need to be considered when interpreting the results of serial and/or late FAST examinations.
