Teaching an old dog new TRICS: re-evaluating transfusion triggers in high-risk cardiac surgery

Use of a restrictive or liberal red blood cell (RBC) transfusion trigger in cardiac surgery (CS) has been the subject of intense debate in the last decade (1-4). Multiple co-morbidities present in CS patients often necessitate perioperative transfusion of RBCs and other allogeneic blood products. CS procedures utilize over 20% of the blood supply in the United States (5). It is well known that allogeneic blood transfusion is associated with increased rates of hospital acquired infection, immunosuppression, circulatory overload, and mortality (6-8). On the other hand, there is some concern that restricting RBC transfusion may result in inadequate oxygen delivery to ischemic tissues, adversely affecting clinical outcomes (9).