Transfusion requirements of patients undergoing routine cardiac surgery

Abstract

Background: Several factors contribute to the need for blood transfusion after cardiac surgery. These include perioperative blood loss, haemodilution on cardiopulmonary bypass, and pre-operative anaemia. Blood and blood products are at a premium and it is advantageous to decrease the burden on transfusion services by requesting fewer blood units to cover routine surgery. It has been customary in the past to cross-match 6 units of whole blood but this figure has been reduced over the years to 4 units and more recently to 2 units. Methods: A retrospective study of the transfusion requirements of our patients over a one-year period (2005-2006) was performed. Transfusions were classified as urgent (i.e. those required in the immediate post-operative period to replace losses and maintain haemodynamic stability) or non-urgent (i .e. those required after the first 24 hours in order to correct a residual anaemia). Results: 1431286 patients (50%) patients were transfused. A total of298 units, average 2.1 units per patient, were transfused. 58 patients received 1 unit of blood, 56 patients received 2 units of blood, 10 patients received 3 units of blood, 7 patients received 4 units of blood, and 12 patients received over 4 units of blood. Sixteen transfusion episodes were urgent, but no undue delay was experienced in administering treatment. Conclusion: The practice of reserving 2 units of packed cells for cardiac surgery has proved safe and adequate. Further studies should be performed in our unit to determine the rate of unnecessary transfusions.