Retransfusion of filtered shed blood in primary total hip and knee arthroplasty: a prospective randomized clinical trial.

BACKGROUND: Allogeneic blood transfusions are associated with a number of well-recognized risks and complications. Postoperative retransfusion of filtered shed blood is an alternative to (reduce) allogeneic blood transfusion. The objectives of this study were to evaluate the clinical efficacy of retransfusion of filtered shed blood and to evaluate the complications, in particular febrile reactions.

STUDY DESIGN AND METHODS: In this clinical trial 160 patients undergoing primary total hip or knee replacement were randomly assigned to receive either a retransfusion system (Bellovac, AstraTech AB) or a regular drain (Abdovac, AstraTech AB). Patients with a preoperative hemoglobin (Hb) level of between 13.0 and 14.6 g per dL were included. The shed blood was returned 6 hours after operation. After surgery the anesthesiologist determined the transfusion trigger. When Hb level dropped below this trigger, an allogeneic blood transfusion was given. The following data were obtained: number of allogeneic blood transfusions, total volume of blood collected in the bag used for retransfusion, perioperative Hb levels, febrile reaction, and other complications.

RESULTS: In the control group 19 percent of the patients received at least one allogeneic blood transfusion. In the study group this percentage was 6 percent of the patients (p = 0.015). Comparing total knee and total hip arthroplasty (control vs. study) the percentages were, respectively, 16 percent versus 2 percent (p = 0.040) and 21 percent versus 11 percent (NS). On average 308 mL of filtered shed blood was retransfused in the study group. In the study group 18 percent of patients had febrile reactions compared to 20 percent in the control group.

CONCLUSION: Postoperative retransfusion of filtered shed blood is effective for decreasing allogeneic blood transfusions after total hip and knee arthroplasty. There was no relationship between retransfusions and postoperative febrile reactions.