With the development of cardiac surgery in the 1950s to correct congenital heart defects came the need for large-volume blood transfusions. In the 1960s and 1970s, the introduction of valve prostheses and direct grafting of coronary arteries made the correction of acquired heart disease a possibility. These landmarks, along with the liberal use of homologous blood transfusion therapy, led to rapid growth of the field. Commensurate with the growth of cardiac surgery as a field was an increasing incidence of transfusion-transmitted hepatitis in the 1970s, ultimately alerting the public and treating physicians to the concept of blood conservation. The emergence of infection by human immunodeficiency virus (HIV) greater heightened the interest in this area, leading to the current practices of blood conservation therapy in cardiac surgery.
Historically, open-heart surgery has been associated with a high usage of blood transfusion. Some reports suggest that up to 70% of this patient population requires blood transfusions, resulting in an average of two to four donor exposures per patient.1,2 It has been reported that 10% of all red blood cell units transfused in the United States are administered during coronary bypass surgery.3 Almost all patients received blood transfusion in the early days of cardiac surgery. However, with an increased awareness of blood-borne infectious diseases, lack of donors, great cost to both the patient and the institution, allergic reaction, blood-type mismatch, and the needs of special populations such as Jehovah's Witnesses, a greater effort has been made to perform open-heart procedures without blood transfusions even in high-risk patients. Advances in perioperative medications that minimize blood loss; greater tolerance of lower hematocrits, especially on bypass; and improvements in surgical techniques resulting in shorter operative times have allowed for these extensive procedures to be performed without significant blood loss.
The high transfusion rates associated with cardiac surgery have been well characterized and are likely caused by the coagulopathy, platelet dysfunction, and red cell hemolysis that occur as a result of the cardiopulmonary bypass circuit.4–6 The introduction of hemodilution using crystalloid pump-priming solution rather than whole blood dramatically reduced the transfusion requirements seen during coronary artery bypass grafting (CABG) procedures.7 Although this technique has reduced the amount of blood transfused during cardiopulmonary bypass (CPB), the resulting hemodilution contributes to the risk of low intraoperative and postoperative hematocrit, especially in patients who weigh less than 70 kg, thereby posing a new risk for transfusion.
Efforts at reducing the use of homologous blood in cardiac surgery began almost 40 years ago. The efforts to decrease allogeneic blood exposures have been a topic of constant review and attention because of the desires of both patients and their physicians to conserve blood during the perioperative period. These joint efforts have affected virtually every aspect of the manner in which heart surgery and CPB are performed. Our experience combined with the experiences of others has led to the development of an integrated, comprehensive blood conservation ...