Acute normovolemic hemodilution in moderate blood loss surgery: a randomized controlled trial

The risks associated with allogeneic blood transfusion are increasingly recognized. More blood is cross-matched for moderate blood loss surgery than any other indication. The role of acute normovolemic hemodilution (ANH) as a blood transfusion strategy was evaluated in a prospective randomized controlled trial. A total of 155 patients undergoing elective hip surgery were randomly assigned to either ANH (n = 78) or standard transfusion (n = 77). ANH on induction of anesthesia was to a target hemoglobin (Hb) level of 110 g per L with return of autologous blood on wound closure. Allogeneic blood was prescribed by an objective transfusion trigger based on an Hb level of less than 80 g per L. Transfusion requirements and postoperative complications were recorded. Allogeneic transfusion was necessary in 22 (29%) standard transfusion patients and 15 (19%) ANH (odds ratio [OR], 0.6; 95% CI, 0.28-1.3; p = 0.23) with 63 and 33 units transfused, respectively (p = 0.1). Significant postoperative complications occurred in 30 (38%) standard transfusion patients compared with 14 (18%) of those randomly assigned to ANH (OR, 0.3; 95% CI, 0.14-0.65; p = 0.009). The major difference between the groups was the frequency of infective complications. Despite modest allogeneic transfusion requirements in hip surgery, ANH reduced postoperative complications.