Elective fresh frozen plasma in the critically ill: what is the evidence?

The scientific rationale for administering fresh frozen plasma (FFP) rests on the assumptions that patients are at risk of adverse effects from inadequate coagulation factors, and that FFP transfusions can decrease those risks. There is a general but unfounded enthusiasm for FFP use across a range of clinical specialties in hospital practice. Plasma for transfusion is most often used when a patient has abnormal results on coagulation screening tests, either as therapy in the face of bleeding, or in patients who are not bleeding as prophylaxis before invasive procedures or surgery. Laboratory abnormalities of coagulation are considered by many clinicians to help predict bleeding before invasive procedures where bleeding risk exists; FFP is presumed to improve the laboratory results and reduce this risk. However, most guideline indications for the prophylactic use of FFP are not supported by evidence from good-quality randomised trials. In fact, the strongest randomised controlled trial evidence indicates that prophylactic plasma for transfusion is not effective across a range of clinical settings. This is supported by data from non-randomised studies in patients with mild-moderate abnormalities in coagulation tests. It is also crucial to clearly understand the risks associated with use of FFP, as no studies have taken adequate account of the extent to which adverse effects might negate the clinical benefits of treatment with FFP. New trials are needed to evaluate the efficacy and adverse effects of plasma, both in bleeding and non-bleeding patients, and to determine whether presumed benefits outweigh the real risks. In addition, new haemostatic tests that better define the risk of bleeding and monitor the effectiveness of FFP use should be validated.