Blood Transfusion Profile in Cardiac Operations

Cardiac operations account for a significant fraction of transfusions in most hospitals, usually around 20% to 30% of the total blood products transfused. The distribution profile of how blood products are transfused in a typical cardiac population follows the Pareto principle (also known as the 80/20 rule or the law of the vital few). This principle, named after economist Vilfredo Pareto, specifies an unequal relationship between inputs and outputs. In the example of blood transfusion in cardiac operations, this principle suggests that 20% of the population (the vital few) account for 80% of the blood products transfused. Figure 1 describes this relationship in graphical form in a typical cardiac surgical population.[1] It is a peculiarity of cardiac surgery that a great deal of focus on blood conservation centers on the 80% of patients who account for 20% of the blood products transfused. Reasons for this disproportionate focus are obscure but may be related to the fact that the sickest patients have the least adverse outcomes associated with transfusion and that other factors besides blood transfusions likely contribute to outcomes in the sickest patients.[2],[3],[4] The following paragraphs attempt to provide a balanced perspective of the transfusion-related benefits and risks in various cardiac surgical populations, especially those that require cardiopulmonary bypass (CPB), keeping in mind that there are certainly patients whose lives are saved by transfusion, whereas others may be harmed.

Figure 1

Transfusion profile in 4446 patients having cardiac procedures using cardiopulmonary bypass.[5]