Abstract
OBJECTIVES: To evaluate the reliability of physician gestalt estimation of pelvic free fluid volume on pediatric Focused Assessment with Sonography for Trauma (FAST). To determine a reliable cut-off volume and characteristics associated with small pelvic free fluid. METHODS: Our study assessed the ability of 2 ultrasound-trained pediatric emergency medicine (PEM) physicians and 2 pediatric radiologists to characterize pelvic free fluid in a retrospective convenience sample of archived FAST from a Level 1 pediatric trauma center, April 2018-June 2020. Inter- and intra-rater reliability were measured to determine the most reliable volume cut-off. Chi-squared and Fisher's exact tests determined characteristics associated with physiologic fluid and fluid volume. RESULTS: Eighty-one (10.2%) of 797 FAST had pelvic fluid and met inclusion criteria. Volume estimates using none/trace/small versus moderate/large classifications were moderately reliable by the PEM physicians (κ = 0.65 [95% CI, 0.63-0.66]; raw agreement = 92%) and radiologists (κ = 0.48 [95% CI, 0.47-0.49]; raw agreement = 91%). This volume cut-off demonstrated higher reliability for both groups and greater agreement for PEM physicians than none/trace versus small/moderate/large. Girls (P = .005), isoechoic (P = .045), and location posterior to bladder (P < .001) were associated with physiologic fluid and hyperechoic (P = .019) with non-physiologic fluid. Hyperechoic (P < .001), anterior (P < .001), lateral (P = .04), or "other" location (P < .001) relative to the bladder were associated with moderate/large volume. CONCLUSIONS: Ultrasound-trained PEM physicians and pediatric radiologists can reliably use gestalt estimation to distinguish moderate or large fluid from smaller pelvic fluid volumes on pediatric FAST.