OC 11.3 - Improved Survival in Severely Bleeding Trauma Patients Treated with Low-titer Group O Whole Blood Compared to Component Therapy

Background: Low-titer group O whole blood (LTOWB) or component therapy (CT) may be used to resuscitate hemorrhaging trauma patients. LTOWB has biologic and logistical benefits and may improve survival.

Aims: Evaluate outcomes in trauma patients treated with LTOWB or CT.

Methods: In this prospective observational study, adult trauma patients with massive transfusion protocol (MTP) activations were enrolled (IRB#201909200). CT group was enrolled from 2017-2019 and LTOWB group from 2019-2021. LTOWB replaced CT in the MTP in 2019, allowing for comparison. Primary outcome was 24-hour mortality. Secondary outcomes included 28-day mortality and 72-hour weight-adjusted total blood product use. Data is presented as median (IQR) or proportions and analyzed via Wilcoxon rank-sum test or Fisher’s exact test. Multivariable logistic regression (MVLR) and adjusted Cox regression were performed to determine independent associations.

Results: We enrolled 384 patients. Patient demographics were similar between LTOWB (N=192) and CT (N=192) cohorts (Table1) with injury severity scores (ISS) of 22(13-33) and 25(17-34) (p=0.026), respectively. Unadjusted 24-hour mortality was not statistically different between LTOWB vs. CT cohorts: 19% vs. 24%, respectively (p=0.322). In stratified analyses, LTOWB was associated with survival for patients with hemostatic dysfunction (Maximum Clot Formation(MCF) < 60mm) and shock (more negative base excess) (Figure1). In an MVLR model, adjusting for MCF and ISS, LTOWB improved the odds of 24-hour survival by 12% (Odds Ratio=0.89; 95% Confidence Interval=0.81-0.97; p=0.011), and also by an adjusted Cox regression model with a Hazard Ratio=0.51; (95%CI=0.27-0.94); p=0.033). The use of LTOWB trended towards improved 28-day survival with a Hazard Ratio=0.66; (95%CI=0.41-1.08); p=0.092), (Figure1E). Additionally, LTOWB patients received significantly less total blood products (80.9(41.6-139.3)mL/kg vs. 48.9(25.9-106.9)mL/kg; p< 0.001).

Conclusion(s): LTOWB treatment in hemorrhagic trauma patients was independently associated with improved 24-hour survival with a 40% relative-reduction in total blood product usage over 72-hours, indicating support for LTOWB in severely bleeding trauma patients with MTP.