A primer on evidence‐based plasma therapy

Abstract

Background and Objectives Although traditionally fresh‐frozen plasma (FFP) has been the product of choice for reversing a significant coagulopathy, the modern blood bank will have several different plasma preparations for use in reversing a significant coagulopathy or arresting coagulopathic bleeding. These products include the aforementioned FFP which is frozen within 8 h of collection, plasma frozen within 24 h after phlebotomy (FP24), and thawed plasma (TP) prepared from either FFP or FP24. Based on their factor levels, these products should all be equally efficacious in reversing a significant coagulopathy although a head‐to‐head comparison between these products has not been performed. Evidence from two systematic literature reviews and numerous observational studies suggest that for a stable patient with a mild coagulopathy, transfusing plasma for an INR ≤ 1·5 does not confer a hemostatic benefit. This lack of benefit is due to the exponential relationship that exists between factor levels and a mildly elevated INR, that is, a large quantity of plasma would be required to produce a reduction in the INR when its pre‐transfusion value is <1·6. By contrast, the relationship becomes more linear when the INR is more significantly prolonged. Thus, even if a reduction in a mildly elevated INR could be achieved with plasma transfusion, the clinical significance of the decrease is dubious and the transfusion itself exposes the recipient to a variety of adverse events such as allergic reactions and transfusion‐related acute lung injury (TRALI). Furthermore, emerging evidence indicates that transfusion‐associated circulatory overload (TACO) following plasma transfusion is an important and under reported adverse event. This review will discuss the various plasma products that are available, describe why the commonly used markers of hemostasis (such as the PT/INR) are not effective markers of perioperative hemostasis, and present some of the current literature on the clinical uses of plasma. Strategies to reduce non‐evidence‐based plasma transfusion, ranging from automated interventions at the time plasma is ordered to more labour‐intensive manual attempts to dissuade providers from ordering plasma unnecessarily, will also be addressed.