Thawing of Fresh Frozen Plasma and Virus-Inactivated Plasma – Suitability of Microwave Oven

Abstract

Background: Microwaves basically are a quick alternative to water bath and water bag system (WB) for thawing of fresh frozen plasma (FFP) for transfusion. Already in the 1980s we developed, together with a manufacturer (Infusotherm, Zeipel, Göttingen, Germany), a microwave oven (MWO) which allowed thawing of FFP much faster and more gentle than with WB. With the addition of e.g. methylene blue or solvents and detergents to plasma for virus inactivation, the question arises if microwaves might have a negative impact on virus-inactivated plasma (VIP) by enhancing activation processes or impairment of proteins which have been initiated by the inactivation procedure, resulting in reduced hemostatic activity. Material and Methods: 30 solvent/detergent-inactivated plasma (SDP), 25 methylene blue-inactivated plasma (MBP), and 30 conventionally produced FFP units were investigated immediately and 2 h after thawing by MWO and a modified WB system for the following coagulation parameters: All plasma clotting factors and the corresponding complex coagulation tests, prothrombin fragment F1+2, d-dimers, thrombin-antithrombin, plasmin-antiplasmin, fibrinogen degradation products, reptilase and thrombin time, antithrombin, protein C, protein S, α2-antiplasmin, von Willebrand factor antigen, Ristocetin cofactor, and von Willebrand factor multimers. The effect on primary hemostasis was investigated by means of in vitro bleeding test (IVBT; Thrombostat 4000, VDG, Seeon, Germany) by addition of plasma to fresh blood of healthy donors. Results: Reaching comparable end temperature (MWO: SDP 31.4 °C, MBP 31.6 °C, FFP 31.7 °C; WB: SDP 32.2 °C, MBP 31.8 °C, FFP 31.5 °C), thawing with MWO (SDP 16.3 min, MBP 19.7 min, FFP 19.5 min) was considerably shorter than with WB (SDP 31.2 min, MBP 31.8 min, FFP 32 min). Under these conditions no significant differences of the hemostatic parameters which could be attributed to the thawing method were found. Only the known differences between the different plasma types which are due to production and inactivation process have been proven. Conclusion: The used MWO is suitable for thawing of FFP as well as VIP. In regard to the significant shorter thawing time, it has clear advantages, particularly in massive transfusion.