Coagulation and Transfusion Medicine / RATIONAL FRESH FROZEN PLASMA TRANSFUSION Toward Rational Fresh Frozen Plasma Transfusion The Effect of Plasma Transfusion on Coagulation Test Results

Numerous published guidelines encourage appropriate use of fresh frozen plasma (FFP). However, adherence is documented as poor. Therefore, we sought to determine the laboratory effect of FFP administration to patients with an international normalized ratio (INR) less than 1.6 (prothrombin time <1.6 times normal). We found minimally prolonged INRs decreased with treatment of the underlying disease alone. Adding FFP to the treatment failed to change the decrease in INR over time. In addition, we observed that the change in the INR per unit of FFP transfused can be predicted by the pretransfusion INR (INR change = 0.37 [pretransfusion INR] – 0.47; r2 = 0.82). With an observed analytic variation of 3.2%, a significant amount of change in the INR following FFP transfusion is expected at an INR of more than 1.7. Indeed, only 50% of patients with an INR of 1.7 showed a significant change in INR with FFP transfusion. Therefore, transfusion for patients not meeting current FFP guidelines does not reliably reduce the INR and exposes patients to unnecessary risk. Current guidelines published by multiple organizations consider fresh frozen plasma (FFP) transfusion appropriate only under specific circumstances.1-15 Although these guidelines vary in the laboratory definition of appropriate FFP transfusion, most suggest a cutoff of a prothrombin time (PT) and/or partial thromboplastin time (PTT) greater than 1.5 times the normal value. Despite these clear guidelines, requests for FFP are the most frequent inappropriate orders received by the blood bank. Clearly, clinicians do not have confidence in the published guidelines. Reported percentages of inappropriate FFP orders vary from institution to institution and range from 10%16 to 83%.17 The most frequent reason for these inappropriate orders, accounting for at least a third of them, is for correction of a prolonged INR in the absence of bleeding.18-20 This prophylactic correction of minor laboratory coagulation abnormalities continues in the absence of evidence of its benefit.21,22 Segal and Dzik22 have suggested that inappropriate FFP orders occur because of 3 assumptions: (1) Elevation of the PT/INR will predict bleeding in the setting of a procedure. (2) Preprocedure administration of FFP will correct the prolonged clotting time results. (3) Prophylactic transfusion results in fewer bleeding events. This study seeks to expand previous work23 and better clarify the second assumption by quantifying the effect of FFP transfusion on laboratory coagulation parameters. Materials and Methods Patients receiving FFP and having pretransfusion and posttransfusion PT/INR measurements were considered for inclusion. Patients with acute trauma, in the operating room,