Prehospital critical care prediction score for emergency transfusion requirements in major trauma: a multicenter validation study

BACKGROUND: Early identification of trauma-patients requiring emergency transfusion remains a critical challenge in prehospital critical care. Massive hemorrhage accounts for approximately 40% of trauma-related deaths and represents the most significant modifiable prognostic factor. Current assessment methods rely primarily on vital signs and physical examination, which have limited sensitivity for detecting compensated shock states. METHODS: We conducted a prospective, multicenter, derivation-validation study across three Spanish Emergency Medical Services systems from January 2021 through June 2025. Adult trauma patients (n = 853) meeting "Code 15" criteria were enrolled from 37 advanced life support units and 6 helicopter emergency medical services. Point-of-care testing was performed prehospitally using the epoc® Blood Analysis System. The primary outcome was emergency transfusion (packed red blood cells or massive transfusion protocol activation) within 24 hours. RESULTS: The derived Prehospital Transfusion Score (PTS) incorporates seven variables: mean blood pressure, Glasgow Coma Scale, pH, calcium, hemoglobin, base excess, and lactate. PTS demonstrated superior discrimination capacity with an area under the curve of 0.881 (95% CI: 0.836-0.925) for emergency transfusion and 0.946 (95% CI: 0.915-0.977) for massive transfusion, significantly outperforming six previously validated scoring systems (p < 0.001 for most comparisons). CONCLUSION: The PTS provides a novel, multidimensional approach for early identification of trauma-patients requiring emergency transfusion by integrating sensitive biomarkers of tissue hypoperfusion, metabolic acidosis, and coagulopathy with traditional hemodynamic parameters. This scoring-system could enhance prehospital triage and facilitate timely activation of massive transfusion protocols.