OBJECTIVE: To comprehensively assess the impact of emergency transfusion of group O washed red blood cells on the vital signs and hematological parameters of patients with severe trauma and to analyze the differential responses among different blood types, thereby providing valuable evidence for optimizing transfusion strategies. METHODS: A retrospective analysis was conducted on the clinical data of patients with severe trauma who underwent emergency transfusion in the hospital's emergency department from April 2023 to March 2024. Changes in blood biochemical indexes and vital signs before and after transfusion were compared, and adverse transfusion reactions were monitored. RESULTS: A total of 65 patients were included in the study, and no adverse transfusion reactions were observed. The shock index (SI) score was 1.07 ± 0.28. Significant changes were noted in platelet count (PLT), activated partial thromboplastin time (APTT), and C-reactive protein (CRP) following transfusion ( CONCLUSION: Timely and effective transfusion of group O washed red blood cells is crucial for stabilizing the vital signs of patients with severe trauma. This approach is not only safe but also feasible, with blood type influencing the response to transfusion. Larger, multi-center studies are warranted to further validate these findings and enhance the generalizability.