Introduction: Since 2018, there has been a vast expansion of prehospital blood programs from less than 10 to greater than 150 in 2024. The trauma adage of the “Trauma Triad of Death” involves limiting hypothermia, acidosis, and coagulopathy. Accordingly, the vast majority of prehospital blood programs have some type of warmer in their system to at least partially warm products before administration; however, there is limited evidence behind this practice in the prehospital setting. When New Orleans EMS began their blood program in 2021, the funding was not available for warmers, and the decision was made to embark on a prehospital cold blood program, with cold pRBC ranging in temperature from 2° to 8° C. This study hypothesized that the administration of 2 units of cold pRBC would not result in hypothermia nor have negative effects on the patients. Methods: This retrospective study used data from New Orleans EMS patient records merged with local hospital patient records from the years 2021 to 2024. Out of the 285 patients who received blood transfusions during this period, a total of 104 patients were included in the study. These patients received 2 units of unwarmed pRBC utilizing a LifeFlow® hand-operated rapid infuser, for a variety of indications including trauma and medical hemorrhages. Results: Patient ages ranged from 15 to 71, with an average of 37 years. 88% were male and 12% were female. 82% of individuals sustained penetrating trauma. The average temperature change was -0.01 °C (95% CI, -0.12 to 0.14) after rapid transfusion of 2 units of unwarmed pRBC. Conclusion: This study demonstrated that unwarmed blood did not cause a clinically significant change in body temperature. These results suggest that blood warmers may not be necessary for prehospital transfusions of 2 units of pRBC or less.
Kling et al. (Sun,) studied this question.