Estimating the risks of prehospital transfusion of D‐positive whole blood to trauma patients who are bleeding in England

<jats:title>Abstract</jats:title><jats:sec><jats:title>Background and Objectives</jats:title><jats:p>D‐negative red cells are transfused to D‐negative females of childbearing potential (<jats:styled-content style="fixed-case">CBP</jats:styled-content>) to prevent haemolytic disease of the foetus and newborn (<jats:styled-content style="fixed-case">HDFN</jats:styled-content>). Transfusion of low‐titre group O whole blood (<jats:styled-content style="fixed-case">LTOWB</jats:styled-content>) prehospital is gaining interest, to potentially improve clinical outcomes and for logistical benefits compared to standard of care. Enhanced donor selection requirements and reduced shelf‐life of <jats:styled-content style="fixed-case">LTOWB</jats:styled-content> compared to red cells makes the provision of this product challenging.</jats:p></jats:sec><jats:sec><jats:title>Materials and Methods</jats:title><jats:p>A universal policy change to the use of D‐positive <jats:styled-content style="fixed-case">LTOWB</jats:styled-content> across England was modelled in terms of risk of three specific harms occurring: risk of haemolytic transfusion reaction now or in the future, and the risk of <jats:styled-content style="fixed-case">HDFN</jats:styled-content> in future pregnancies for all recipients or D‐negative females of <jats:styled-content style="fixed-case">CBP</jats:styled-content>.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>The risk of any of the three harms occurring for all recipients was 1:14 × 10<jats:sup>3</jats:sup> transfusions (credibility interval [<jats:styled-content style="fixed-case">CI]</jats:styled-content> 56 × 10<jats:sup>2</jats:sup>–42 × 10<jats:sup>3</jats:sup>) while for females of <jats:styled-content style="fixed-case">CBP</jats:styled-content> it was 1:520 transfusions (<jats:styled-content style="fixed-case">CI</jats:styled-content> 250–1700). The latter was dominated by <jats:styled-content style="fixed-case">HDFN</jats:styled-content> risk, which would be expected to occur once every 5.7 years (<jats:styled-content style="fixed-case">CI</jats:styled-content> 2.6–22.5). We estimated that a survival benefit of ≥1% using <jats:styled-content style="fixed-case">LTOWB</jats:styled-content> would result in more life‐years gained than lost if D‐positive units were transfused exclusively. These risks would be lower, if D‐positive blood were only transfused when D‐negative units are unavailable.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>These data suggest that the risk of transfusing RhD‐positive blood is low in the prehospital setting and must be balanced against its potential benefits.</jats:p></jats:sec>