Anemia and red blood cell transfusion

Introduction Red cell transfusion is an extremely common medical intervention. In the United States, more than 16 million red blood cell (RBC) units are transfused annually to 3.4 million patients.Worldwide, 85 million units of blood are collected per year. In Northern England, about 50% of units are given tomedical patients, and 40% to surgical patients; hip replacement and coronary artery bypass graft (CABG) surgery were the most common surgical indications. RBC units are also frequently administered to critically ill patients, as a supportive therapy to patients receiving chemotherapy and marrow transplants, and to patients with blood loss frommedical conditions such as gastrointestinal bleeding. Approximately 25% of all red cells transfused are given to patients with a primary diagnosis of cardiac disease, and 8% of all cardiology admissions are transfused RBCs. In recent years, blood use is declining as clinicians adopt a more restrictive approach to transfusion. The latest estimates of the cost of a RBC unit range from $522 to $1183 (mean, $761± $294). This chapter reviews the current knowledge about red cell transfusion and the risk posed by anemia. This overview summarizes preclinical, observational data but emphasizes randomized clinical trials. Guidelines on transfusion practices are examined. The first three sections are based on systematic reviews of the literature. The fourth section describes an approach to decision making in red cell transfusion that is occasionally evidence based, but frequently based on the authors’ views.