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.peer-reviewe