Over the past 30 years, trauma surgeons in Europe and Japan have demonstrated the proficient use of ultrasonography in evaluating blunt trauma patients.1–9 During the 1990s, emergency physicians and trauma surgeons in North America have prospectively evaluated the applications of ultrasonography in trauma and have presented results comparable with those of other investigators worldwide.10–18
The focused assessment with sonography for trauma (FAST) examination is a bedside screening tool to aid clinicians in identifying free intrathoracic or intraperitoneal fluid. The underlying premise behind the use of the FAST examination is that clinically significant injuries will be associated with the presence of free fluid accumulating in dependent areas. The FAST examination was originally developed as a limited ultrasound examination, focusing primarily on the detection of free fluid, and was not designed to universally identify all sonographically detectable pathology. While a number of groups have subsequently recommended additions or modifications to the standard FAST examination, such as evaluating for pneumothoraces, quantifying the degree of free intraperitoneal fluid present, or following the accumulation of the free fluid, the essence of the examination remains identifying findings that can be interpreted by clinicians in a clinical context.
The rapid and accurate diagnosis of injuries sustained by trauma patients can be difficult, especially when they are associated with other distracting injuries or altered mental status from head injury or drug or alcohol use. In the United States, the three generally accepted diagnostic techniques for evaluating abdominal trauma patients are diagnostic peritoneal lavage, computed tomography (CT) of the abdomen, and ultrasonography. Each of these diagnostic modalities has its own advantages and disadvantages.
Diagnostic peritoneal lavage remains an excellent screening test for evaluating abdominal trauma. The advantages of diagnostic peritoneal lavage include its sensitivity, availability, relative speed with which it can be performed, and low complication rate. A unique advantage of diagnostic peritoneal lavage is its ability to detect early evidence of bowel perforation. Disadvantages, however, include the potential for iatrogenic injury, its misapplication for evaluation of retroperitoneal injuries, and its lack of specificity.
Computed tomography of the abdomen has a greater specificity than diagnostic peritoneal lavage, thus making it the initial diagnostic test of choice at many trauma centers. Oral and intravenous (IV) contrast material should be given to provide optimal resolution. Advantages of CT include its ability to precisely locate intra-abdominal lesions preoperatively, to evaluate the retroperitoneum, to identify injuries that may be managed nonoperatively, and its noninvasiveness. The disadvantages of CT are its expense, time required to perform the study, need to transport the trauma patient to the radiology suite, the need for contrast materials, and a radiation exposure that may be quite significant in the typically young trauma population if this modality is used liberally.
Ultrasonography offers several advantages over diagnostic peritoneal lavage and abdominal CT. Numerous studies have demonstrated that the FAST examination, like diagnostic peritoneal lavage, is an accurate screening tool for abdominal ...