17 Mar 2026
The results from the SWIFT (Study of Whole blood In Frontline Trauma) trial have been published in the New England Journal of Medicine (NEJM), providing new evidence on the use of ‘whole blood’ transfusions in pre-hospital care.
The study – led by NHS Blood and Transplant and spearheaded by London's Air Ambulance Charity – began in December 2022 and involved 10 UK air ambulance charities in partnership with the Ministry of Defence and Air Ambulances UK.
Exploring whether giving whole blood on scene could improve survival and reduce the need for further transfusions once in hospital, the trial analysed 616 trauma patients: 314 receiving whole blood and 302 receiving standard care.
The study found:
- The primary outcome (death or massive transfusion within 24 hours) occurred in 48.7% of the whole blood group and 47.7% of the standard care group
- There was no statistically significant difference between the two approaches
- Mortality at all time points and rates of massive transfusion were similar between groups
- Safety outcomes were comparable.
While the trial didn’t demonstrate improved outcomes with whole blood, publication in NEJM – one of the world’s most respected peer-reviewed medical journals – reflects the significance and quality of the research. The findings provide critical evidence to inform future clinical guidance, procurement decisions and research priorities across the NHS and pre-hospital medicine sector.
Professor Laura Green, co-chief investigator for SWIFT, Associate Medical Director for Research and Development at NHS Blood and Transplant, Professor of Haemostasis and Transfusion Medicine at Queen Mary University of London, and Consultant in Haemostasis and Transfusion Medicine at Barts Health NHS Trust, said:
“The contribution of everyone involved in the trial – from air ambulance pilots, blood service, our blood donors and supporters to the trial team and military medics – will help guide the future care of people experiencing traumatic, life-threatening bleeds.
“The trial did not show a benefit from whole blood but in providing that answer it will help us improve trauma care. We are thankful to the participating air ambulance organisations and Defence Medical Services for collaborating with us to drive innovation and research for seriously ill patients.”
Blood is used extensively by London’s Air Ambulance – with red blood cells and plasma as separate components. We’re the only ones in London who can provide a blood transfusion on scene, which is regularly required when someone is critically injured.
All blood used in British healthcare comes from the same source – donations from the general public. These blood donations enable air ambulances, both in London and the rest of the country, to give patients the best possible care. Find your nearest blood donation venue here.