This meta-analysis, which includes 29 randomised controlled trials for a total of 2439 patients, evaluates the effectiveness of acute normovolemic haemodilution (ANH) to reduce the number of allogeneic red blood cell (RBC) units transfused in adult patients undergoing all types of cardiac surgery. Results from 21 studies were included in the analysis.
Overall, ANH reduced the number of RBC units (mean difference -0.79 [-1.25 to -0.34; P = 0.001] and the number of patients transfused (mean difference: -0.64 [-0.97 to -0.31; P<0.0001]. However, severe statistical heterogeneity and the fact studies with and without a predefined transfusion protocol were mixed in the analysis limit the interpretation of these data. – Philippe Van der Linden