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Medical ultrasound was introduced in the 1950s but it wasn’t until the early 1970s that the first case of visceral injury detected by ultrasound was described.1 Throughout the next decade, technological advances made “real-time” images, and therefore the more practical application of ultrasound, possible. The utility of ultrasound in trauma began investigation in the late 1980s and in 1992 the first prospective study utilizing ultrasound for the detection of hemoperitoneum was published.2
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We have come a long way in our understanding of ultrasound since then, and countless reports and studies of ultrasound for the rapid evaluation of intra-abdominal injury have emerged. Up to 40% of patients who have sustained traumatic injury to the abdomen may have no significant findings on physical examination. Furthermore, invasive or traditional radiographic methods of evaluation may be impractical in the unstable patient. Therefore, there is a role for a rapid, noninvasive test to detect the presence of free intraperitoneal, pericardial, and pleural fluid in the setting of acute blunt or penetrating chest and abdominal trauma. The Focused Assessment with Sonography for Trauma (FAST) examination has proven to be the most sensitive and specific test for this purpose, and is supported by the American College of Surgeons (ACS) in the advanced trauma life support (ATLS) course.
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Trauma ultrasound has proven to be particularly useful in hemodynamically unstable patients, those with hypotension of unknown etiology, and in the setting of an equivocal physical examination.3 Studies have shown the FAST examination to be 69–95% sensitive with a specificity of 95–100% for identifying intraperitoneal bleeding in hemodynamically unstable patients.3 Emergency ultrasound is now used widely for multiple diagnostic purposes and to help guide various bedside procedures. In addition to accurately detecting free fluid in the abdomen, it has become an established tool in the evaluation of biliary disease, aortic aneurysms, ectopic pregnancy, cardiac pathology, pneumothorax, and hemothorax. In fact, it is nearly 100% sensitive for detecting a pericardial effusion or hemothorax and is equivalent to chest radiography in identifying a traumatic pneumothorax.4 The FAST examination can accurately recognize cardiac injuries from penetrating trauma and has become the basis of the extended FAST (E-FAST), which includes thoracic views for the identification of pneumothorax, in some trauma centers.5
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Ultrasound is both portable and noninvasive and can be used easily in the evaluation of trauma victims without interfering with definitive therapy. On average, the FAST examination can be performed within 2–4 minutes, usually simultaneously with other resuscitative measures, and can provide useful information without the delay imposed by other imaging modalities such as CT scan or diagnostic peritoneal lavage (DPL). In one recent randomized controlled trial, point-of-care limited ultrasonography was found to decrease the time to definitive surgical treatment by 64% in patients with torso trauma, reduce the number of CT scans obtained, decrease the length of hospital stay, and result in fewer complications.6
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Studies have also shown that nonradiologist ...