Background: Trauma is a leading cause of morbidity and mortality in children of all ages. Computerized tomography (CT) has become the test of choice for diagnosing intra-abdominal injury (IAI) in pediatric blunt abdominal trauma but also carries the risk of malignancy from radiation exposure. The Point of Care Ultrasound (POCUS) Focused Assessment with Sonography for Trauma (FAST) is radiation free and may obviate the need for CT in some adult patients. We conducted a systematic review and meta-analysis to evaluate the utility of POCUS FAST in the diagnosis of IAI in pediatric blunt abdominal trauma.
Methods: We searched medical literature from January 1966 to March 2018 in PUBMED, EMBASE, and Web of Science. Our search yielded 741 individual articles, of which 698 were excluded by title or abstract. The remaining 43 articles were reviewed in their entirety. Among these full texts, only prospective studies of POCUS FAST exams in diagnosing IAI in pediatric trauma were included in our final analysis. Sensitivity, specificity, and likelihood ratios (LR) were calculated using a random-effects model (95% Confidence Interval). Study quality and bias risk were assessed, and test-treatment threshold estimates were performed.
Results: Eight prospective studies were included encompassing 2,135 patients with a weighted prevalence of IAI of 13.5%. Studies had variable quality with most at risk for partial and differential verification bias. POCUS FAST exams for IAI had a pooled sensitivity of 35% (95% CI: 29%-40%), specificity 96% (95% CI: 95%-97%), LR+ 10.84 (95% CI: 4.36-26.92), and LR- 0.64 (95% CI: 0.51-0.80). A positive POCUS FAST post-test probability for IAI (63%) exceeds the upper limit (57%) of our test-treatment threshold model for CT abdomen with contrast. A negative POCUS FAST post-test probability for IAI (9%) does not cross the lower limit (0.23%) of our test treatment threshold model.
Conclusion: In a hemodynamically stable child presenting with blunt abdominal trauma, a positive POCUS FAST exam means IAI is likely, but a negative POCUS FAST exam alone cannot preclude further diagnostic workup for IAI. The need for a CT scan may be obviated in a subset of low-risk pediatric blunt abdominal trauma patients presenting with a Glasgow Coma Scale of 14-15, normal abdominal exam, and negative POCUS FAST.