Focused abdominal sonography for trauma (FAST) is used as a rapid assessment tool for patients with severe blunt abdominal trauma. The use of bedside ultrasound in the diagnostic evaluation of trauma originated in Europe. By the early 1990s, FAST was being increasingly used in North America. Several reports concluded that FAST is a rapid and effective means of evaluating an adult after blunt abdominal trauma (1,2,3,4). FAST examinations are usually performed by surgeons or emergency physicians. In its policy statement, the American College of Emergency Physicians supports the use of emergency ultrasound (5). FAST is now considered an alternative to diagnostic peritoneal lavage or abdominal computed tomography (CT) in the Advanced Trauma Life Support course (6). The procedure offers several advantages: (a) it is rapid and noninvasive; (b) it can be performed at the bedside during the secondary survey and simultaneously with other diagnostic and therapeutic interventions; and (c) it is relatively easy to learn (particularly important for clinicians who are not imaging specialists), as the test does not focus upon the imaging of any particular organ. FAST may potentially identify organ pathology or injury, but the examination itself is limited only to the detection of fluid. The role of FAST in penetrating trauma is unclear.

Despite its advantages, the utility of FAST has been questioned in terms of its sensitivity and in regard to both the experience and training of the operator (7,8,9,10,11). Some argue that hemoperitoneum is an inadequate indicator of abdominal visceral injury. In a series of 575 adult patients with abdominal visceral injuries, 157 (34%) had no evidence of hemoperitoneum either on CT scan or at the time of surgery. The FAST examination was falsely negative in 26 cases (17%) (12). Additional controversy surrounds the use of FAST for children. Some studies have reported excellent sensitivity (92.5% to 100%) in pediatric patients and have strongly advocated its use (13,14). Others have reported much less favorable results, with sensitivities ranging from 30% to 55% (15,16,17,18). These studies report a number of significant injuries not detected by the FAST examination, including bowel injuries (with and without intraperitoneal air), liver laceration, adrenal hematoma, renal laceration, splenic laceration, and perinephric hematoma. Such conflicting literature has resulted in considerable debate as to whether FAST should be utilized at all in pediatric trauma patients, but the issue remains to be settled. Certainly, there is evidence indicating that a FAST examination should be interpreted with caution with pediatric patients, and the interpretation of a negative examination should include careful correlation with other clinical information.