Reevaluation of FAST Sensitivity in Pediatric Blunt Abdominal Trauma Patients: Should We Redefine the Qualitative Threshold for Significant Hemoperitoneum?

Abstract

The utility of the focused assessment with sonography in trauma (FAST) examination in hemodynamically stable pediatric blunt abdominal trauma (BAT) patients is controversial.We report our 3-year experience with FAST performance to detect greater than physiologic amounts of intraperitoneal fluid after BAT. We performed a retrospective chart review of all FAST examinations performed from July 2015 to June 2018 at a level I pediatric trauma center. The main outcome of interest was the performance of a concerning FAST (cFAST) compared with a computed tomography scan diagnosis for greater than physiologic levels of free fluid (FF) and clinical follow-up. A cFAST was defined by the presence of any FF in the upper abdomen or by a moderate to large amount of FF present in the pelvis. The interobserver reliability of cFASTwas assessed with Cohen κ coefficient. Locations of FF were assessed. A total of 448 FAST cases were eligible for review. The median age was 11 years with 64% male. Thirty-one FAST examinations (6.9%) were positive for some amount of FF; 18 (4.0%) were cFASTs. In the cFAST group, 11 patients (61%) were hemodynamically stable. The cFAST had a sensitivity of 89% (95% confidence interval [CI], 65%-99%), specificity of 99% (95% CI, 98%-100%), positive predictive value of 89% (95% CI, 67%-97%), and negative predictive value of 99% (95% CI, 98%-100%). The positive and negative likelihood ratios were 191 (95% CI, 47-769) and 0.11 (95% CI, 0.03-0.41). The κ coefficient for cFASTwas 0.72 with 86% agreement. Free fluid on cFAST cases was observed in the pelvis (78%), right upper quadrant (44%), and left upper quadrant (44%). In pediatric BAT patients, a cFAST has acceptable sensitivity and remains a highly specific test to rule in greater than physiologic quantities of FF with confidence.