Safety of a Restrictive versus Liberal Approach to Red Blood Cell Transfusion on the Outcome of AKI in Patients Undergoing Cardiac Surgery: A Randomized Clinical Trial

Background Safely reducing red blood cell transfusions can prevent transfusion-related adverse effects, conserve the blood supply, and reduce health care costs. Both anemia and red blood cell transfusion are independently associated with AKI, but observational data are insufficient to determine whether a restrictive approach to transfusion can be used without increasing AKI risk. Methods In a prespecified kidney substudy of a randomized noninferiority trial, we compared a restrictive threshold for red blood cell transfusion (transfuse if hemoglobin= 0.3 mg/dl within 48 hours of surgery, or >= 50% within 7 days of surgery. Results Patients in the restrictive-threshold group received significantly fewer transfusions than patients in the liberal-threshold group (1.8 versus 2.9 on average, or 38% fewer transfusions in the restricted threshold group compared with the liberal-threshold group; P