Accuracy of reporting estimated blood loss in open repair of pelvic and acetabular fractures

Abstract

Background: Pelvic injuries after blunt trauma are often repaired with open reduction-internal fixation (ORIF), often resulting in high blood loss. We compare calculations of estimated perioperative blood loss (EPBL) against reported intraoperative blood loss (RIBL) by visual estimation to evaluate their accuracy during ORIF for pelvic fractures.

Materials and Methods: A retrospective observational study was conducted at a Level 1 trauma center. 142 patients requiring ORIF of acetabular and/or pelvic ring fracture between ages 18 to 89 years from 3/1/2017 to 2/28/2019 were included. EPBL was calculated by Gross Method. Statistical analyses were conducted using R statistical software. Medians and inter-quartile ranges were used to summarize variables. A two-sample Wilcoxon signed rank test was performed. The agreement and reproducibility of RIBL and EPBL were examined with concordance correlation coefficients (CCC) and Bland-Altman plots.

Results: Median RIBL was 450 mL [250, 800], while median EPBL was 2142 mL [1213, 3607]. The median difference was -1692 mL (p<0.001). The Bland-Altman plot showed consistent under-reporting in RIBL versus EPBL. A proportional bias (p<0.001), indicated that the level of bias was not constant between levels of blood loss. The CCC between RIBL and EPBL was 0.076 [-0.016, 0.167]. Pearson’s Correlation Coefficient was 0.213 (p=0.011). RIBL and EPBL had a weak positive correlation.

Discussion: Blood loss during ORIF calculated by EPBL was significantly higher than RIBL. Our results suggest that blood loss reporting may be inaccurate in ORIF of pelvic fractures. These findings necessitate formulation of an accurate method permitting proper blood loss reporting.

Keywords: postoperative blood loss; surgical blood loss; orthopedic surgery; estimation techniques