Intraoperative Low-volume Acute Normovolemic Hemodilution in Adult Open-heart Surgery

Background: Recently, various studies have questioned the efficacy of intraoperative acute normovolemic hemodilution (ANH) in reducing bleeding and the need for allogeneic transfusions in cardiac surgery. The aim of the present study was to reevaluate the effects of a low-volume ANH in elective, adult open-heart surgery. Methods: Two hundred four consecutive adult patients undergoing cardiac surgery were prospectively randomized in a non-blinded manner into two groups: ANH group (103 patients), where 5-8 ml/kg of blood was withdrawn before systemic heparinization and replaced with colloid solutions, and a control group, where no hemodilution was performed (101 patients). Procedures included single and multiple valve surgery, aortic root surgery, coronary surgery combined with valve surgery, or partial left ventriculectomy. The purpose of the study was to evaluate the efficacy of ANH in reducing the need for allogeneic blood components. Routine hematochemical evaluations, perioperative blood loss, major complications, and outcomes were also recorded. Results: No differences were found between the groups regarding demographics, baseline hematochemical data, and operative characteristics. There was no difference in the amount of transfusions of packed red cells, fresh frozen plasma, platelet concentrates, total number of patients transfused (control group, 36% vs. ANH group, 34.3%; P = 0.88), and amount of postoperative bleeding (control group, 412 ml [313-552 ml] vs. ANH group, 374 ml [255-704 ml]) (median [25th-75th percentiles]); P = 0.94. Further, perioperative complications, postoperative hematochemical data, and outcomes were not different. Conclusions: In patients undergoing elective open-heart surgery, low-volume ANH showed lack of efficacy in reducing the need for allogeneic transfusions and postoperative bleeding.