Association Between Prehospital Blood Transfusion in Helicopter Emergency Medical Services and Survival: A Retrospective Population-Based Cohort Study.
Air medical journal · 2025-12-09 · Registry study
Abstract
OBJECTIVE: Critical hemorrhage is a life-threatening condition in which blood transfusion is an essential lifesaving intervention. Although the importance of prehospital blood transfusion is increasingly recognized, its effectiveness remains unclear, particularly in Asian health care settings. This study aimed to characterize patients receiving prehospital blood transfusion through helicopter emergency medical services (HEMS) and evaluate their association with survival outcomes in a Japanese population-based cohort. METHODS: We conducted a retrospective evaluation of data from the Japanese Society for Aeromedical Services Registry from April 2020 to March 2023. This study included adult patients transported by physician-staffed HEMS. Propensity score matching (1:4) was used to adjust for confounding factors. The primary outcome measure was patient survival until hospital discharge. RESULTS: Among the 24,776 patients, 71 (0.3%) received prehospital blood transfusions using type O packed red blood cells. Transfusion recipients had lower systolic blood pressures (83 mm Hg vs. 138 mm Hg; P < .001) and higher rates of external causes of injury (80.3% vs. 51.1%; P < .001) than did those who did not receive a transfusion. After propensity score matching (N = 230), prehospital transfusion was associated with improved survival (odds ratio [OR], 2.09; 95% confidence interval [CI], 1.05-4.18). The results of the trauma subgroup analysis showed no statistically significant association (OR, 1.88; 95% CI, 0.80-4.40). CONCLUSION: In Japan's physician-staffed HEMS, prehospital blood transfusion was appropriately provided to patients with hemorrhagic shock and, after adjustment for confounding factors, was associated with improved survival. These findings provide evidence supporting the potential benefits of prehospital blood transfusion in appropriately selected patients within physician-staffed air medical systems.