FAST as a predictor of clinical outcome in blunt abdominal trauma

Abstract

Background. Peer-reviewed literature demonstrates increasing support for the use of focused abdominal sonography in trauma (FAST) in the setting of blunt trauma, one study demonstrating the sensitivity and specificity of FAST for the detection of free fluid to be 0.64 - 0.98 and 0.86 - 1.00, respectively, compared with abdominal CT. Utilising ultrasound in trauma triage increases efficiency and cost-effectiveness and reduces reliance on CT, compared with using CT alone. There is little evidence to support relying solely on a negative FAST and physical examination for patient management.
 Method. A retrospective descriptive study of 172 adult patients who received FAST for the evaluation of blunt abdominal trauma between 22 July 2007 and 21 January 2008 at Tygerberg Hospital was performed. Ultrasound findings were correlated with CT scan findings, operative findings if managed surgically, clinical outcomes whether managed surgically or conservatively, as well as postmortem findings in deceased patients.
 Results. FAST was negative in 147 (85.5%) patients. Twenty-four (16.3%) of these patients died from all-cause mortality, none of which was due to intra-abdominal injury. 
 Seven patients with negative FAST underwent CT scan owing to change in clinical course, and 3 patients with negative FAST underwent laparotomy owing to change in clinical course, with positive findings in 2 patients – a bowel injury requiring resection (not seen on CT) and a diaphragmatic rupture seen on CXR. A negative FAST was shown to be an excellent predictor for the absence of significant intra-abdominal trauma.
 The mortality rate among 25 FAST positive patients was 24% (N=6). Only one of these patients (with a splenic rupture) was suspected to have died from abdominal pathology.