Is Blood Conservation Optimally Utilized?

Blood conservation and the subsequent prevention of transfusion have assumed an increasingly important role in cardiac surgery. The concern is one of preventing transmission of transfusion related diseases and of conserving an extremely valuable resource (1,2). Cardiac surgery with cardiopulmonary bypass has become the most common operation performed, thus attracting much analysis of transfusion practices. It is estimated that of the approximately 250,000 cardiopulmonary bypass procedures done in the United States each year, the majority require transfusion of blood products (3). It has been calculated that the cardiac surgery services throughout the United States use somewhat over 10% of all the blood product resources that are transfused in this country (4,5). Many methods of blood conservation have been described (Table 1), but there still exists a wide variance in blood product utilization for adult patients undergoing cardiopulmonary bypass procedures. A review of the literature reveals average packed red blood cell transfusion rates from 0.3 up to 8 units per patient (4,6-8). If we further add the transfusion of platelets, fresh frozen plasma, and cryoprecipitate, the total donor exposure to the patient goes up substantially more. A varied patient population has been cited as the reason for these discrepancies but it has been demonstrated in similarly matched groups of patients receiving transfusions, that the patterns were based to some extent upon "prevailing practice" rather than on need (9,10).