J Trauma Acute Care Surg. 2019 Aug 28;Epub ahead of print

# SAFETY PROFILE AND IMPACT OF LOW-TITER GROUP O WHOLE BLOOD FOR EMERGENCY USE IN TRAUMA.

Williams J, Merutka N, Meyer D, Bai Y, Prater S, Cabrera R, Holcomb J, Wade C, Love J, Cotton B

PURPOSE: Following US military implementation of a cold-stored whole blood program, several US trauma centers have begun incorporating uncrossmatched, group O cold-stored whole blood into civilian trauma resuscitation. We set out to evaluate the safety profile, transfusion reactions events, and impact of low-titer group O whole blood (LTO-WB) at our center.

METHODS: In November 2017, we added LTO-WB to each of our helicopters and to our emergency department (ED) refrigerator, alongside that of existing RBCs and plasma. We collected information on all trauma patients receiving prehospital or ED transfusion of uncrossed, emergency release blood products between 11/17 and 06/18. Patients were divided into those receiving any LTO-WB and those receiving only RBC and or plasma (COMP). Serial hemolysis panels were obtained at 3-hrs, 24-hrs, and 48-hrs. All data was run using STATA 12.1. Statistical significance was set at p<0.05.

RESULTS: 198 patients received LTO-WB and 152 patients received COMP. There were no differences in age, sex, or mechanism. LTO-WB patients had higher chest AIS scores (median 3 vs. 2; p=0.027), as well as worse arrival base excess (median -7 vs. -5; p=0.014) and lactate (5.1 vs. 3.5; p<0.001). LTO-WB patients received less post-ED blood products than the COMP patients (median 0 vs. 3; p=0.001). There was no difference in survival (LTO-WB 73%, COMP 74%; p=0.805). There were only two suspected transfusion reactions, both in the COMP group (p=0.061). There was no difference in hemolysis panel values. Controlling for age, severity of injury and prehospital physiology, LTO-WB was associated with a 53% reduction in post-ED blood product transfusion (OR 0.47; 0.23-0.94; p=0.033) and two-fold increase in likelihood of survival (OR 2.19, 1.01-4.76, p=0.047).

CONCLUSIONS: LTO-WB has similar evidence of laboratory hemolysis, similar transfusion reaction rates, and is associated with a reduction in post-ED transfusions and increase likelihood of survival.Level of evidence Level II, Prospective comparator study without negative effect.