Prehospital Whole Blood Trial Finds No Superiority in Traumatic Hemorrhage

Key Takeaways

• Prehospital whole blood was not superior to standard component therapy for the 24-hour composite endpoint.
• Patients with major traumatic hemorrhage were randomized to up to 2 units of whole blood or up to 2 units each of red cells and plasma before hospital arrival.
• Secondary outcomes were similar overall, prothrombin times above the normal range were more frequent with whole blood, serious adverse events were numerically fewer, and thrombotic events were similar.

In a pragmatic randomized NEJM trial across 10 air ambulance services in England, prehospital type O whole blood was not superior to standard blood-component care for major traumatic hemorrhage. The primary composite occurred in 48.7% and 47.7% of the two groups, respectively, with a relative risk of 1.02, 95% CI 0.80 to 1.31, and P=0.84. Patients were assigned to up to 2 prehospital units of whole blood or blood components before hospital arrival. The investigators concluded that 2 units of prehospital whole blood were not superior to standard care for that outcome.

The study used a pragmatic, phase 3, multicenter, unblinded, randomized, superiority design within England’s participating air ambulance services. Eligible patients had major traumatic hemorrhage and were attended in the prehospital setting by a participating air ambulance service. The trial tested whether whole blood could lower the risk of death or massive transfusion within 24 hours after randomization. Among 942 randomized patients, 616 entered the analysis after exclusions for nontraumatic hemorrhage or traumatic cardiac arrest. The analyzed groups included 314 assigned to whole blood and 302 assigned to standard care.

The primary endpoint combined death from any cause with massive transfusion within 24 hours after randomization. Massive transfusion was defined as receipt of at least 10 units of blood components or products. Death at all assessed time points, massive transfusion itself, and other secondary outcomes were similar between groups. No secondary domain separated the groups in a consistent direction. Across these efficacy measures, the overall pattern was similar between the two prehospital strategies.

Laboratory and safety findings were also broadly similar, although prothrombin times above the normal range were more frequent with whole blood. Those values were 40.7% in the whole-blood group and 30.5% in the standard-care group, while serious adverse events occurred in 31 and 37 participants, respectively. Thrombotic events were similar in the two groups.

The authors concluded that 2 units of prehospital whole blood were not superior to standard care for the 24-hour composite endpoint in this pragmatic prehospital system.