Ultrasound performed by radiologists-confirming the truth about FAST in trauma

For hemodynamically stable patients with suspected abdominal injuries, the diagnostic accuracy of computed tomographic scans remains unmatched. Focused assessment with sonography for trauma (FAST) is useful in trauma evaluation to identify intraabdominal fluid early in the unstable patient. In skilled hands, sensitivity is shown to be close to 100%. However, some recent studies have questioned its sensitivity in subgroups at risk of bleeding. In most studies, hemodynamic markers of instability have been limited to hypotension. The purpose of this study was to determine the sensitivity and specificity of initial FAST for detection of hemoperitoneum in the potentially unstable patient as judged by objective hemodynamic parameters available early during resuscitation.

Prospective observational study at a major European trauma center. FAST was performed in trauma patients by the trauma team radiologist. The study population consisted of the subgroup deemed potentially unstable on arrival as defined by systolic blood pressure < or =90 mm Hg, pulse rate > or =120, or base deficit > or =8. Results were compared with one of the following reference standards: computed tomographic scan, diagnostic peritoneal lavage, exploratory laparotomy, or observation.

One hundred and four patients constituted the study group. There were 75 true-negative, 10 false-negative, 16 true-positive, and 3 false-positive FAST results. Sensitivity and specificity were 62% and 96%, positive and negative predictive values 84% and 89%, respectively, and overall accuracy was 88%.

A negative initial FAST in hemodynamically unstable patients, even in the hands of radiologists, cannot reliably exclude intraabdominal bleeding. These patients should undergo additional diagnostic tests to exclude intraperitoneal hemorrhage.