University of Washington/Seattle Children's/BloodworksNW, Washington, United States
Background/Case Studies: Administering platelets through a rapid infuser reservoir is proven to be safe. However, the clinical significance of infusing ABO incompatible platelets with red blood cells (RBCs) remains unclear. There is a theoretical risk that isoagglutinin in the plasma of a platelet unit could interact with RBCs and induce hemolysis, resulting in the infusion of hemolyzed cells that can lead to adverse reactions associated with excessive potassium and free hemoglobin (Hb). In order to understand if this could result in in vivo hemolysis that could have clinical significance, we performed in vitro studies of RBC transfusions with incompatible platelets in plasma.
Study
Design/Methods: A total of seven in vitro studies were performed including five cases (type A RBC and type O platelet) and two controls (type A RBC and type A platelet). The units were less than 24 hours past their expiration date. Anti-A platelet titer was measured in type O platelets to see if titer level would affect hemolysis. One RBC unit was infused, followed by one platelet unit into the rapid infuser reservoir. The units remained mixed for 30 minutes, and 200 mL of the mixture was drained from the reservoir at 200 mL/min as wastage. Then a 10 mL sample was collected from the end of the post-pump patient line. The primary outcome was to determine the presence of in vitro hemolysis before and after mixing based on the following parameters: direct antiglobulin test (DAT), free Hb, hemolysis check, and direct agglutination.
Results/Findings: The results are presented in Table 1. The post-mix DAT was positive for IgG in all test samples (5/5), and weakly positive for complement in 3/5. The changes in free Hb in test cases between measured and calculated post-mix spanned 0.9-3.4g/dL. Post-mix hemolysis check was negative in 3/5 and slightly positive in 2/5 cases, with no significant differences when compared with the negative controls. Anti-A platelet titers ranged from 16 to 512 and did not appear related to the presence of hemolysis. All tests were negative for direct agglutination. Conclusions: Our study suggested that mixing ABO minor incompatible platelets with RBCs in a rapid infuser reservoir does not induce overt in vitro hemolysis. These findings support the use of rapid infusers regardless of platelet compatibility allowing for an efficient resuscitation. Whether there is any clinically significant risk in transfusing IgG-coated RBCs remains to be explored.
Importance of research: Whether ABO incompatible platelets are safe to mix with RBCs in a rapid infuser during acute bleeding is unclear. There is a theoretical risk that isoagglutinin in plasma of platelet can interact with RBCs and induce in vitro hemolysis. The comparison of laboratory values between pre- and post-mixing indicated absence of hemolysis in post-mixing samples. Infusing RBCs with incompatible platelets in a rapid infuser can be an option during acute bleeding by providing more efficient transfusion.
