History and Practice of Acute Normovolemic Hemodilution

Purpose for Review The purpose of this review is to provide an overview of recent literature on acute normovolemic hemodilution (ANH) and conclude a consensus of beneficial effects. Recent Findings Newfound interest in blood conservation has increased the generalizability of ANH. Overall ANH reduces transfusion rate by 20–30% with a minimum of 650 ml whole blood (WB) removed. Greater effects have also been experienced with ≥ 1000 ml WB. With ANH, allogenic red blood cells (RBCs) and non-RBC transfusion rates are reduced intraoperatively and postoperatively. In addition, decreased length of stay and decreased incidence of pulmonary infections have been experienced. However, large volume resuscitation with colloid or crystalloid increases the risk for endothelial dysfunction and dilutional coagulopathy. ANH is still limited by anemia and small body surface area (BSA) but could be overcome by blood substitutes. Summary ANH might be helpful in decreasing perioperative blood transfusions in addition to current blood conservation techniques. Further investigation is needed to expand applicable patient demographic and to define the optimal method for performing ANH.