Transfusion of Whole Blood Is Not Associated With Increased Rate of Hemolytic Transfusion Reaction

Low-titer cold-stored whole blood (WB) transfusion provides multiple advantages over component therapy (CT) in resuscitation of the hemorrhaging patient. However, concern regarding the risk of hemolytic transfusion reaction (HTR) is a barrier for continued expansion of the use of WB. HTR is most often seen after transfusion of packed red blood cells (RBCs), and the rate of HTR after WB transfusion remains largely unknown. We sought to investigate the incidence of HTR after WB transfusion at our institution via a retrospective observational study. Given that the pathogenesis of HTR is often an immune-mediated response to RBC antigens, we hypothesized that the incidence of HTR in WB transfusion would not be higher than in CT.

The institutional blood bank was queried for the total number of units transfused in the facility and all suspected transfusion reactions from CT (RBC, fresh-frozen plasma [FFP], or platelets) or WB between July 2020 and June 2023. A retrospective chart review was performed to determine the type and severity of reaction and the implicated product. The primary outcome was incidence of HTR. Secondary outcomes were incidence of severe transfusion reaction (including transfusion-associated cardiac overload, transfusion-related acute lung injury, and severe allergic reactions) and in-hospital mortality related to transfusion reaction.

Two HTRs occurred out of 6,771 units of WB transfused (incidence 0.03%), compared to 6 HTRs out of 49,802 units of RBCs (incidence 0.012%, P = .25 via Fisher's exact test). One severe reaction occurred in the WB subgroup (0.01%); 8 occurred with RBC (0.02%). In patients with suspected transfusion reaction, there was no difference in mortality between WB (1, 0.01%) and RBC transfusion (7, 0.01%). No HTR was seen in patients who received prehospital transfusion of WB, RBC, or platelets (no patient received prehospital FFP). No HTR was seen with transfusion of platelets or FFP.

This retrospective study found no difference in incidence of HTR, severe transfusion reaction, or mortality with transfusion of WB when compared to CT, in particular RBC. These findings underpin the assertion that WB is a safe method of resuscitation and supports the expanded utilization of WB in both in-hospital and prehospital settings, and has implications in both civilian and deployed settings.