Transfusion interventions in critical bleeding requiring massive transfusion: a systematic review

Critical bleeding (CB) requiring massive transfusion (MT) can occur in a variety of clinical contexts and is associated with substantial mortality and morbidity. In 2011, the Australian National Blood Authority (NBA) published patient blood management guidelines for CB and MT, which found limited high-quality evidence from which only 2 recommendations could be made. The aim of this systematic review (SR) was to update these guidelines and identify evidence gaps still to be addressed. A comprehensive search was performed for randomized controlled trials (RCTs) and SRs using MeSH index and free text terms in MEDLINE, the Cochrane Library (Issue 11, 2012), EMBASE, CINHAL, PUBMED, and the Transfusion Evidence Library up to July 15, 2014. The evidence was grouped according to 4 questions based on the original guideline relating to transfusion interventions: (1) effect of dose, timing, and ratio of red blood cells (RBCs) to component therapy on patient outcomes; (2) effect of RBC transfusion on patient outcomes; (3) effect of fresh frozen plasma, platelet, cryoprecipitate, fibrinogen concentrate, and prothrombin complex concentrate on patient outcomes; and (4) effect of recombinant activated factor VII (rFVIIa) on patient outcomes. From this search, 19 studies were identified: 6 RCTs and 13 SRs. Two of the RCTs were pilot/feasibility studies, 3 were investigating rFVIIa, and 1 compared restrictive versus liberal RBC transfusion in upper gastrointestinal hemorrhage. Overall, limited new evidence was identified and substantial evidence gaps remain, particularly with regard to the effect of component therapies, including ratio of RBC to component therapies, on patient outcomes. Clinical trials to address these questions are required.