Blood transfusion practice today.

In trying to develop a cohesive and logical transfusion strategy, one must try to keep all of the previously mentioned information in mind. While recognizing that RBC transfusions are an integral part of care for critically ill patients, one also must recognize that there are large amounts of data that associate multiple transfusions of allogeneic blood with increased risk of morbidity and mortality. Some data exist showing causation and association, such as studies demonstrating the immunomodulatory effects of allogeneic transfusions. In addition, the blood supply is a limited resource that should not be used indiscriminately. It therefore behooves clinicians to subject each unit of blood transfused to scrutiny. In all likelihood, patients who are not actively bleeding and who are not hypovolemic probably get little to no benefit from allogeneic blood transfusions while their hemoglobin is greater than 7 g/dL. They do, however, get needless exposure to a potentially toxic substance. Although it is the authors' hope that more research will be performed to clarify the risks and benefits of blood transfusion, the authors also hope that knowledge of already published studies will continue to spread and replace the unfounded practices of the past.