In Reply: We agree with Drs Dixon and Santamaria that differences in bleeding may have accounted for some of the variability we observed between centers in transfusion rates for red blood cells, platelets, and fresh frozen plasma. The Society of Thoracic Surgeons Adult Cardiac Surgery Database does not record estimated blood loss; therefore, this variable could not be analyzed. We minimized the effect of this potential confounder by selecting a very homogeneous analysis population, ie, isolated primary CABG with cardiopulmonary bypass. Because of multiple factors, such as capture of shed blood using cardiotomy suction and autologous blood salvage systems using centrifugation, an accurate estimation of blood loss is challenging in cardiac surgery with cardiopulmonary bypass.
Bennett-Guerrero E, Ferguson TB, Song HK. Blood Transfusion After Coronary Artery Bypass Graft Surgery—Reply. JAMA. 2011;305(2):149-150. doi:10.1001/jama.2010.1957