No Mortality Difference Between Prehospital Whole Blood and Component Therapy

Prehospital transfusion with low-titer group O whole blood (LTOWB) did not reduce 30-day mortality compared with component therapy in trauma patients at risk for hemorrhagic shock, according to a phase 3 trial published in the New England Journal of Medicine.

The Type O Whole Blood and Assessment of Age during Prehospital Resuscitation (TOWAR) trial, led by investigators at the University of Pittsburgh and University of Pittsburg Medical Center (UPMC), enrolled 1,020 severely injured patients transported by air medical services to 11 U.S. trauma centers. Participating air bases were cluster-randomized to administer up to two units of LTOWB or standard component therapy consisting of red blood cells, plasma or both during one-month treatment blocks.

Among the 993 patients included in the modified intention-to-treat analysis, 30-day mortality was 25.9% in the whole blood group and 20.5% in the component therapy group, a difference that was not statistically significant after adjusting for clustering and baseline imbalances. Mortality at 3, 6 and 24 hours, as well as in-hospital mortality, were similar in the LTOWB and component groups.

Investigators also evaluated whether whole blood storage age affected outcomes. In an observational substudy, 30-day mortality did not differ significantly between patients who received whole blood stored for 1 to 14 days and those who received blood stored for 15 to 21 days (26.4% versus 27.1%, respectively). Rates of adverse events, organ failure, infection and acute respiratory distress syndrome were also similar across groups.

While investigators noted several trial limitations that may have reduced differences between the study arms, they said the findings may increase flexibility in civilian and military prehospital transfusion practices.

“This is good news,” said co-lead author Francis Guyette, MD, professor of emergency medicine at the University of Pittsburgh’s School of Medicine, in a UPMC news release. “It means that emergency responders can use whatever form of blood is most accessible to them.”