Radiographic bladder shift is a harbinger of intraoperative blood loss in acetabular surgical fixation

Purpose: The purpose of this study was to characterize the relationship between a novel radiographic measurement on initial AP pelvis radiograph (termed “bladder shift,” BS) to intraoperative blood loss (IBL) during acetabular surgical fixation. Methods: All adult patients receiving unilateral acetabular fixation (Level 1 academic trauma; 2008–18) were reviewed. AP pelvis radiographs were reviewed for visible bladder outlines and then measured to determine the percentage deformation toward the midline. Hemoglobin & hematocrit data were then used to calculate quantitative blood loss between pre- and post- operative blood counts for data analysis. Results: 371 patients with unilateral traumatic acetabular fractures requiring fixation were reviewed; 99 of these had visible bladder outlines, complete blood count and transfusion data (2008–2018; 66% associated patterns). Median bladder shift (BS) was 13.3%. Every 10% of bladder shift was associated with 123 mL greater IBL. Patients with full bladder shift to midline sustained a median 1.5L IBL (interquartile range [IQR] 0.8 to 1.6). Associated patterns had a threefold greater median BS (associated: 16.5% [15.4 to 45.9] vs. elementary: 5.6% [1.1 to 15.4], p < 0.05) and received intraoperative pRBC twice as frequently (57% vs. 24%, p < 0.01). Conclusions: Radiographic bladder shift is an easily available visual marker, in patients sustaining acetabular fractures, that may predict intraoperative hemorrhage and need for transfusions.