Whole Blood Versus Blood Components in Prehospital Care.

Objectives: Whether clinical outcomes differ for hemorrhaging patients receiving prehospital whole blood versus blood component transfusion is unclear. Furthermore, most prehospital transfusion studies are limited to injured patients and commingle interfacility transfers with 9-1-1 scene responses. This study assessed outcomes exclusively among 9-1-1 scene response patients receiving prehospital transfusion with either whole blood or blood components for traumatic and non-traumatic hemorrhage.

Methods: Using the ESO Data Collaborative for 2019- 2023, patients 8 to 100 years old who received whole blood or blood components were identified. Interfacility transports, patients receiving blood products prior to EMS arrival, and those with pre-arrival cardiac arrest were excluded. The primary prehospital outcome was change in shock index, along with changes in individual vital signs (Glasgow coma score (GCS), heart rate, systolic blood pressure). The primary hospital outcome was mortality at emergency department (ED) or hospital disposition. We also analyzed adverse events.

Results: Of 1,990 eligible patients, 1,515 received whole blood and 475 received blood components. There were significant baseline differences between the two groups, with whole blood more frequently used by ground ambulance services, in urban areas and for penetrating trauma. Patients receiving blood components had statistically greater decreases in shock index (median change, -0.3 vs. -0.2, p = 0.040) and heart rate (median change, -7 bpm vs. - 4 bpm, p = 0.007), but there was no significant difference in mortality for patients receiving whole blood vs. blood components after multivariable analysis adjusting for baseline differences (adjusted odds ratio: 1.7, CI: 0.6-4.9). No patients in either group received prehospital epinephrine, and there were no ED diagnoses of transfusion reaction. Three whole blood patients had diagnoses related to thromboembolic events, but these were unlikely to be related to the transfusion.

Conclusions: In this retrospective observational study of 9-1-1 scene response patients with traumatic or non-traumatic hemorrhage, differences between shock index and heart rate for patients receiving whole blood or blood components were of questionable clinical significance, and adjusted mortality did not significantly differ for the two groups. There were no instances of prehospital anaphylaxis or ED transfusion reactions. Both transfusion strategies appear equally effective and safe.