Patients with penetrating abdominal injuries require rapid, cost-effective assessment that can detect all significant injuries without exposing the patient to unnecessary delays or complications. Physical examination can be inaccurate, while other diagnostic modalities have advantages and drawbacks. Focused assessment with sonography for trauma (FAST) is a rapid, portable, ultrasonographic screening tool developed mainly to detect free peritoneal or pericardial fluid. Kirkpatrick and colleagues evaluated the role of FAST in the assessment of patients admitted to two major trauma centers, one U.S. and one Canadian.
At both participating centers, all critically injured patients were assessed by a team led by a trauma surgeon or a trauma fellow. This person performed handheld FAST examinations on 38 patients before other evaluation was undertaken. The FAST examinations were interpreted before other investigations were done. The complete patient assessment typically was carried out by another team member. The handheld FAST assessments were compared with the final assessment based on several modalities, including floor-based ultrasonographic screening, computed tomographic screening, and operative or autopsy findings.
Compared with conventional ultrasonographic screening examination, the handheld FAST accurately diagnosed free intraperitoneal fluid in 11 of the 12 patients with free intraperitoneal fluid. Sensitivity was 92 percent, and specificity was 100 percent. In the only false-negative case, the examining surgeon was interrupted by an urgent case, which could have contributed to the negative interpretation. The diagnosis of free fluid was made within seconds using handheld ultrasonographic screening and the diagnostic impression was so strong that, in positive cases, the examiner proceeded to intervention without conducting assessment of all sites. Handheld FAST also was moderately successful in detecting intraperitoneal injuries.
The authors conclude that the handheld FAST provides an extremely rapid and reliable test for free intraperitoneal fluid in severely injured patients. Because the presence of free intraperitoneal fluid after penetrating trauma almost always indicates significant injury, the use of handheld FAST could avoid delay and the need for extensive investigation in these patients. The authors recommend that negative examinations be followed by more extensive diagnostic evaluation because of the limited ability of handheld FAST to reliably detect intra-abdominal injuries.