Out-of-hospital blood component transfusion: a systematic review

BACKGROUND AND OBJECTIVE. On average 45 units of blood components per 1000 population were transfused in Europe in 2019, a year when Spain registered a total of 856 473 units transfused. A high percentage of trauma cases attended by emergency responders involve patients with massive bleeding, and such patients are the ones who receive most of the out-of-hospital transfusions. Our purpose was to analyze available evidence on out-of-hospital blood component transfusions.
METHODS. Systematic review of the literature in the following databases up to February 2023: Web of Science, the Cumulated Index in Nursing and Allied Health Literature, PubMed, and Scopus. Search terms were chosen from among the English Medical Subject Headings and descriptors the parallel Spanish health sciences list (DECS). To evaluate article quality we used checklists from several sources (Cochrane, STROBE [Strengthening the Reporting of Observational Studies in Epidemiology], CHEERS [Consolidating Health Economic Evaluation Reporting Standards], and PRISMA [Preferred Reporting Items for Systematic Reviews]).
RESULTS. Thirty-two articles were reviewed. The main causes of hemorrhagic shock were trauma and intestinal bleeding. Protocols for out-of-hospital transfusion differ from country to country. Survival after prehospital blood-component or tranexamic-acid transfusion was associated with better survival than crystalloid transfusion.
CONCLUSIONS. The studies included in this review provided data that support prehospital transfusion of blood components, although research to provide more evidence is needed.