Synergistic blood‑sparing effect of acute normovolemic hemodilution combined with intraoperative cell salvage in major orthopedic surgery: a randomized controlled trial

Abstract Purpose To evaluate the blood‑sparing efficacy and safety of acute normovolemic hemodilution (ANH) combined with intraoperative cell salvage (ICS) versus ICS alone in major orthopedic surgery. Methods Sixty patients undergoing elective major orthopedic surgery were enrolled in this single‑center, prospective, randomized controlled trial. Patients were randomly assigned 1:1 to either the ANH + ICS group ( n = 30) or the ICS group ( n = 30). The primary outcome was the total perioperative volume of allogeneic red blood cell (RBC) transfusion. Secondary outcomes included intraoperative and postoperative transfusion rates, perioperative hematological parameters, transfusion‑related costs, and safety indicators. Results The total perioperative allogeneic RBC transfusion volume was significantly lower in the ANH + ICS group than in the ICS group (median 0 U [IQR, 0 to 1] vs. 1 U [IQR, 0 to 3.25]; Z = 2.750, P = 0.006). The postoperative transfusion rate decreased from 60.00% to 23.33% ( P = 0.004; ARR: 36.7%; NNT: 2.7), and the postoperative transfusion volume was also significantly lower ( P = 0.001). Intraoperative transfusion did not differ significantly. The ANH + ICS group maintained higher perioperative hemoglobin levels ( P group = 0.016). Coagulation parameters, hypotension incidence, and vasopressor requirements were similar between groups. Transfusion‑related costs were significantly lower in the ANH + ICS group ( P = 0.009). Logistic regression identified the combined strategy as a factor associated with a lower likelihood of postoperative transfusion (OR = 0.236, 95% CI 0.071 to 0.786, P = 0.019). Conclusions ANH combined with ICS significantly reduces perioperative allogeneic RBC transfusion and costs, maintains higher hemoglobin, and does not compromise coagulation or hemodynamic safety.