Reliability of Physician Estimation of Pelvic Free Fluid Volume on the Pediatric Focused Assessment With Sonography for Trauma

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.