[Cost-effectiveness analysis of an autotransfusion program in primary knee and hip replacement surgery]

To evaluate the cost-effectiveness of a program for autotransfusion in patients undergoing primary prosthetic surgery of the knee and hip (cemented and non-cemented).

A case-control comparison. Retrospective group: review of case histories of patients undergoing surgery in 1993, screened to identify the subpopulation that would be candidates for a program of autotransfusion and to evaluate the blood transfusion policy. Prospective group: patients undergoing surgery between 1995 and 1996 who participated in an autotransfusion program. We studied the following variables in both groups: prevalence of exposure to homologous blood and the amount, perioperative course of hemoglobin/hematocrit, and mean cost of the blood treatment given. In the prospective group we examined agreement between autologous blood extracted before surgery and later reinfused.

The prevalence of exposure to homologous blood fell significantly from the retrospective to the prospective phases as follows: knee surgery 43.8% to 11.6%, cemented hip replacement 75% to 17.4%, non-cemented hip replacement 73.5% to 15.2%. The amount of packed red cells from homologous blood also fell: knee surgery 0.9 +/- 1.1 units to 0.2 +/- 0.5 units, cemented hip replacement 1.4 +/- 1 to 0.3 +/- 0.6 units, non-cemented hip surgery 1.8 +/- 1.3 to 0.3 +/- 0.7 units. The most commonly used techniques were preoperative donation and postoperative blood salvage from drains. The mean direct costs of hemotherapy in the prospective phase (homologous + autologous) were greater than in the retrospective phase, with the highest costs incurred in cases using autotransfusion (preoperative donation + blood salvage). The least differences in cost were seen in preoperative donation, which was also associated with the lowest rate of reinfusion in knee surgery.

The autotransfusion program described is effective for lowering and even preventing exposure to homologous blood. The efficacy of the program is adequate, though it could be improved. The costs related to autologous hemotherapy are greater when combined autotransfusion techniques are used. When only one technique is used, the best cost-benefit ratio comes with preoperative donation.