What is the utility of the Focused Assessment with Sonography in Trauma (FAST) exam in penetrating torso trauma?

STUDY OBJECTIVE: A recent Cochrane Review has demonstrated that emergency ultrasonography decreases the amount of computerised tomographic scans in blunt abdominal trauma.13 However, there is no systematic review that has evaluated the utility of the Focused Assessment with Sonography for Trauma(FAST) exam in penetrating torso trauma. We systematically reviewed the medical literature for the utility of the FAST exam to detect free intraperitoneal blood after penetrating torso trauma.

METHODS: We searched PUBMED and EMBASE databases for randomised controlled trials from 1965 through December 2009 using a search strategy derived from the following PICO formulation of our clinical question:

PATIENTS: patients (12+ years) sustaining penetrating trauma to the torso.

INTERVENTION: FAST exam during their initial trauma workup. Comparator: either local wound exploration (LWE),computerised tomography (CT), diagnostic peritoneal lavage (DPL), or laparotomy.

OUTCOME: intraperitoneal and pericardial free fluid. The methodological quality of the studies was assessed.Qualitative methods were used to summarise the study results.

ANALYSIS: Sensitivities and specificities were compared using a Forest Plot (95% CI) calculated by Revman 5 (Review Manager Version 5.0. Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration,2008) between the FAST exam and definitive diagnostic modalities such as LWE, CT, DPL, or laporotomy.

RESULTS: We identified eight observational studies (n=565 patients) that met our selection criteria. The prevalence of a positive FAST exam after penetrating trauma was fairly low ranging from 24.2% to 56.3%.The FAST exam for penetrating trauma is a highly specific (94.1–100.0%), but not very sensitive (28.1–100%) diagnostic modality.

CONCLUSION: From the review of the literature, a positive FAST exam has a high incidence of intraabdominal injury and should prompt an exploratory laparotomy. However, a negative initial FAST exam after penetrating trauma should prompt further diagnostic studies such as LWE, CT, DPL, or laparotomy.