[Decrease in allogenic transfusions due to the spread of use of postoperative retransfusion systems in knee replacement surgery]

Cost-effectiveness of post-operative cell salvage in total knee arthroplasty. Should we continue to recommend its use today?

OBJECTIVES

Total knee arthroplasty (TKA) has a high transfusion rate. In our protocol, the use of postoperative cell salvage is indicated in patients with contraindications to tranexamic acid (TA). An analysis was performed on the effect of post-operative cell salvage (POCS) regarding transfusion rate and costs in patients undergoing TKA.

MATERIAL AND METHODS

A prospective analysis was conducted on 518 patients, of whom 434 received TA, and 84 were contraindicated. The red cell mass, blood volume, and the percentage of lost blood volume were calculated. Incidents associated with the use of post-operative re-perfusion of drained blood and the rate of transfusion were recorded. An analysis was performed on the costs associated with allogeneic transfusion prevention methods.

RESULTS

A POCS drain was not inserted in 10 out of the 84 patients not candidates for TA. In the 74 in which it was placed, 158±72ml of red cell mass was reinfused. The allogeneic transfusion rate was 36%, and was 52% in those with no drain inserted. Relative risk of transfusion using POCS was 0.69 (0.41 to 1.16) with an absolute risk reduction of 16% (-8 to 40%). The number needed to treat to avoid allogeneic transfusion was 7. The direct costs to avoid allogeneic transfusion were €1,610. No complications associated with blood re-infusion were observed.

CONCLUSIONS

The use of POCS would be required in 7 patients after TKA to avoid one allogeneic transfusion with a cost over 10 times that of a transfusion of red cell concentrates.