Establishing Causation in Transfusion Medicine and Related Tribulations

Abstract

0887-7963/$ see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.tmrv.2010.11.010 B OTH BLOOD BANKERS and clinicians practiced “faith-based”medicine for 5 decades (1940-2000) by transfusing red blood cells (RBCs) to patients with hemoglobin falling to less than or equal to 10 g/dL. The Transfusion Requirements in Critical Care (TRICC) randomized controlled trial (RCT) then demonstrated that, without adverse outcomes, a transfusion trigger of 7 g/dL produced a result superior to a transfusion trigger of 10 g/dL. In fact, normovolemic intensive care unit (ICU) patients randomized to receive RBCs for a hemoglobin falling to less than or equal to 10 g/dL had a significant (P b .05) increase in the risk of myocardial infarction and pulmonary edema, as well as in-hospital mortality, compared with subjects randomized to receive allogeneic blood transfusion (ABT) for a hemoglobin falling to less than or equal to 7 g/dL. Furthermore, several trends —30-day, 60-day, or ICUmortality; multiple-organ dysfunction score; occurrence of any complication; and acute respiratory distress syndrome—favored the restrictive (rather than liberal) transfusion arm. The only exception pertained to patients with coronary heart disease in whom the trends tended to be reversed. For this reason, the Functional Outcomes in Cardiovascular Patients Undergoing Surgical Hip Fracture Repair RCT randomized more than 2000 patients with coronary heart disease undergoing hip fracture repair