SWiFT Trial Finds No Advantage to Prehospital Whole Blood in Patients With Life-Threatening Trauma

Prehospital whole blood transfusion was not associated with improved survival or a reduction in the need for massive transfusion compared with standard component therapy in patients with life-threatening traumatic hemorrhage, according to findings from a multicenter randomized trial published in the New England Journal of Medicine.

Large-scale comparative evidence on prehospital transfusion strategies has been limited. In the United Kingdom, patients typically receive red blood cells and plasma as separate components. However, interest in whole blood is growing, driven in part by potential operational advantages in the prehospital setting, including simpler storage and transport, reduced kit weight and faster administration.

The phase 3 Study of Whole Blood in Frontline Trauma (SWiFT) trial, conducted across 10 air ambulance services in England, evaluated whether administering up to two units of leukocyte-depleted whole blood in the prehospital setting improved outcomes compared to standard care with red blood cells and plasma. The trial enrolled 942 patients; 616 were included in the primary analysis (314 in the whole-blood group and 302 in the standard-care group).

The composite primary outcome, defined as mortality from any cause or receipt of a massive transfusion within 24 hours, occurred in 48.7% of patients in the whole-blood group and 47.7% of those receiving standard care. Mortality at all measured time points, rates of massive transfusion and other secondary outcomes were similar between groups. Slightly fewer serious adverse events were reported in the whole-blood group (31 versus 37, respectively).

The researchers noted several limitations. The dose used – up to two units – may have been insufficient to detect a benefit. The study’s pragmatic design may have introduced heterogeneity in patient selection, with variability in treatment delivery and prehospital conditions potentially influencing outcomes. 

While the trial did not demonstrate improved outcomes, NHSBT emphasized that the findings, including planned cost-effectiveness analyses, will help build a more complete understanding of the role of whole blood in clinical practice in the U.K.

“This trial did not show a benefit from whole blood, but in providing that answer it will help us improve trauma care,” said co-chief investigator Laura Green, MD, of NHS Blood and Transplant and Queen Mary University of London.