Is Low-titer Type O Whole Blood Superior to Blood Components in Prehospital Trauma Care?
In recent years, there has been a growing interest in using low-titer type O whole blood (LTOWB) for trauma patients in hospital settings and, increasingly, in prehospital care. This shift has sparked a crucial question: Is LTOWB transfusion truly superior to traditional component therapy (i.e., red blood cells (RBCs), plasma, and platelets) for trauma patients in prehospital care?
Carter BloodCare began supplying LTOWB to hospitals in 2020, soon followed by air ambulances. A few years later ground ambulances started requesting blood for prehospital transfusion, after initially using RBCs and liquid plasma. In response to increasing demand, Carter BloodCare made LTOWB available to ground ambulances. Carter BloodCare collects LTOWB using CPDA-1 anticoagulant-preservative, which allows for a 35-day shelf life, compared to collecting blood in the typical container that uses CPD as the anticoagulant-preservative which has a 21-day shelf-life. This additional 14 days of shelf-life allows unused blood to be sent to the hospital partner, reducing expiration.
The use of LTOWB in trauma care is appealing because it simplifies resuscitation by delivering all essential blood components in a single unit and takes up much less valuable space on ambulances. Early studies suggested that LTOWB may offer advantages over component therapy including reduced time to administration and improved outcomes. However, while many believe LTOWB to be superior, particularly in life-threatening hemorrhage, the evidence to support this belief is still inconclusive. Although numerous retrospective and single-center prospective studies have shown a potential survival benefit with LTOWB, no large-scale randomized controlled trial (RCT) has been performed to conclusively demonstrate its superiority over component therapy.
The Eastern Association for the Surgery of Trauma work group recently published a systematic review and meta-analysis of 21 studies on the resuscitation of trauma patients with LTOWB. The findings led the group to make a conditional recommendation for using LTOWB in adult civilian trauma patients receiving blood transfusion. The group noted that the overall quality of evidence was very low, limiting their ability to make strong recommendations either for or against LTOWB use.
The SWiFT (Study of Whole Blood in Frontline Trauma) trial, conducted in the United Kingdom, evaluated whether prehospital LTOWB transfusion was superior to blood component therapy in trauma patients. The trial began in December 2022 and aims to recruit 848 participants and compare the outcomes of patients receiving LTOWB versus blood components in prehospital settings.
The primary goal of the SWiFT trial is to determine whether prehospital LTOWB transfusion reduces the proportion of participants who experience death or massive transfusion within the first 24 hours. This study may help establish whether LTOWB should become the new standard of care for pre-hospital trauma patients. The trial is expected to be completed by December 2024, and its findings could have significant implications for emergency trauma care worldwide.
While the demand for LTOWB in prehospital settings is growing rapidly, the question of whether it is superior to blood components remains unanswered. Although retrospective and observational studies have provided valuable insights, a large-scale RCT is essential to definitively determine whether transfusion of LTOWB is statistically superior to the transfusion of blood components.
References
1. Smith JE, Barnard EBG, Brown-O'Sullivan C, Cardigan R, Davies J, Hawton A, Laing E, Lucas J, Lyon R, et al. The SWiFT trial (Study of Whole Blood in Frontline Trauma) – the clinical and cost effectiveness of pre-hospital whole blood versus standard care in patients with life-threatening traumatic haemorrhage: study protocol for a multi-centre randomised controlled trial. Trials. 2023 Nov 14;24(1):725. doi: 10.1186/s13063-023-07711-4.
2. Christofer MD, Reynolds JM, Haines KL, Kasotakis G, Freeman JJ. Whole blood resuscitation for injured patients requiring transfusion: A systematic review, meta-analysis, and practice management guideline from the Eastern Association for the Surgery of Trauma. Journal of Trauma and Acute Care Surgery. 2024 Sep;97(3):460-470. doi: 10.1097/TA.0000000000004327.