Blood procurement is a vital national priority that is met in the United States by volunteer donors and a pluralistic blood collection program that includes the American Red Cross, independent community blood centers, and hospitals. More than 15 million units of whole blood are collected from approximately 10 million donors annually. Recruitment of donors is preceded by a medical history and limited physical examination. The donated blood is subjected to tests of blood type, red cell antibodies, and infectious agents that may be transmitted by blood transfusion. In some cases, collection of red cells, platelets, leukocytes, or plasma is achieved by hemapheresis. Plasma for the subsequent manufacture of derivatives such as albumin and intravenous immunoglobulin is obtained from paid donors by for-profit organizations different from those that collect whole blood and prepare blood components. The meticulous attention to donor risk characteristics and the use of sensitive assays to detect infectious agents that may be transmitted by blood have greatly improved the safety of blood.
It is widely accepted that red blood cell (RBC) transfusions save lives and prevent ischemia-related morbidity in severely hemorrhaging patients and those with acute anemia (hemoglobin [Hgb] less than 6 g/dL). When a patient's Hgb level exceeds 10 g/dL, oxygen delivery and consumption do not necessarily increase with RBC transfusions. For patients in the 6 to 10 g/dL Hgb “gray zone,” the benefit of a transfusion depends upon a patient's clinical status and should be weighed against the inherent risks of allogeneic blood.
These risks include adverse reactions, which occur in up to 3 percent of transfusions. Transfusion-related acute lung injury is the number one cause of transfusion-related fatalities, and new pathogens causing transfusion-transmitted infections continue to pose a threat to the blood supply. Transfusion-associated circulatory overload is often not recognized, but is associated with increased morbidity and prolonged lengths of stay.
As the aging population grows in the United States, the demand for blood will increase, even as the donor population declines. Patient blood management efforts are growing in popularity as hospitals grapple with the risks and costs associated with transfusion. The implementation of evidence-based practice is the best way to benefit patients and minimize the risks of transfusion.
Acronyms and Abbreviations
2,3-BPG, 2,3-bisphophosglyceric acid,; AABB, American Association of Blood Banks; AHTR, acute hemolytic transfusion reaction; APACHE II, Acute Physiology and Chronic Health Evaluation II; ATR, allergic transfusion reaction; BCSH, British Committee for Standards in Haematology; BNP, B-type natriuretic peptide; CI, confidence interval; CMV, cytomegalovirus; CPD, citrate, phosphate, and dextrose; DAT, direct antiglobulin test; DHTR, delayed hemolytic transfusion reaction; ESA, erythropoiesis-stimulating agents; FNHTR, febrile non-hemolytic transfusion reactions; FOCUS trial, Transfusion Trigger Trial for Functional Outcomes in Cardiovascular Patients Undergoing Surgical Hip Fracture Repair; G-CSF, granulocyte colony-stimulating factor; GVHD, graft-versus-host disease; Hct, hematocrit; Hgb, hemoglobin; HLA, human leukocyte antigen; HNA, human neutrophil antigen; HPC-A, hematopoietic progenitor cells obtained by apheresis; HPC-C, hematopoietic progenitor cells obtained from umbilical cords; HSCT, hematopoietic stem cell transplant; ...