Focused assessment of sonography in trauma (FAST) has been shown useful to detect clinically significant hemoperitoneum in adults, but not in children. Several studies, including a meta-analysis have attempted to assess the performance of FAST in identifying children with intra-abdominal injuries (IAIs) from blunt abdominal traumas (BAT).
In a prospective observational study on 357 children with blunt abdominal trauma, FAST sensitivity = 52% for significant hemoperitoneum, specificity = 96%, PPV = 48%; NPV = 97%. In the meta-analysis, the identification of hemoperitoneum using FAST protocol (for intra-peritoneal fluid only) the pooled estimate of sensitivity was 80% and specificity 96%. For the identification of any IAI using FAST protocol the pooled estimate of sensitivity was 66% and specificity was 93%.
Bottom line:
In children with BAT, FAST has a low to moderate sensitivity but high specificity to detect clinically important free fluid. While a positive FAST suggests hemoperitoneum and abdominal injury, a negative FAST cannot be used to reliably rule out IAI.
References:
1. Holmes J F, Gladman A, Chang C H. Performance of abdominal ultrasonography in pediatric blunt trauma patients: a meta-analysis. Journal of Pediatric Surgery 2007; 42(9): 1588-1594.
2. Fox JC, Boysen M, et al. Test characteristics of focused assessment of sonography for trauma for clinically significant abdominal free fluid in pediatric blunt abdominal trauma. AcadEmerg Med. 2011 May;18(5):477-82.
