Abstract
Background
In the literature are different data about the allogenic blood transfusion rate after total knee replacement. The common intention in orthopedic surgery is to reduce the requirement for allogenic blood transfusions by optimizing the blood management. The aim of this study is to determine the efficacy of the mechanical autotransfusion system OrthoPAT® to reduce the postoperative allogenic blood transfusion (ABT) rate.
Method
According to the preliminary performed power analysis we did a prospective controlled study including 151 patients which were randomized in a group A (OrthoPAT® for intra- and postoperative blood salvage and retransfusion, n=76 patients) and a control group B (no retransfusion system was used, n=75 patients). All patients had a primary osteoarthritis of the knee and were operated on without use of a tourniquet. We implanted in all patients a cemented posterior stabilized total knee prosthesis design. In group A the autotransfusion system was used for 6 hours (intra- and postoperatively) and the collected blood was retransfused. The retransfused blood was anticoagulated, filtered and centrifuged to separate waste products. Red cells were washed with saline and reconcentrated to a high hematocrit. The preoperative data for cardiopathy, angiopathy, preoperative anemia or anticoagulant treatment showed no significant differences for group A and B. Because of missing data we finally were able to use the results of 140 patients: 70 group A and 70 in group B. The indications for a blood transfusion were influenced by the clinical symptoms of anemia, the hemoglobin value (hemoglobin < 8.0 g/dl) and the anamnesis of cardiovascular diseases. Evaluation was done with the medical history and the pre-/postoperative hemoglobin values and postoperative need of allogenic blood transfusion.
Results
The two groups showed no significant differences relating to the demographic data or the medical history. 23 patients (33 %) of the retransfusion group who in mean received 281 ml of salvaged blood needed allogenic blood transfusion compared with 23 patients (33 %) of the control group B (p=0,999). The hemoglobin values of group A versus the control group showed after the donation of the salvaged blood a tendency to a higher hemoglobin value (p=0,062) but no longer at the third and fifth day postoperative.
Conclusions
In this clinical observation the use of the autotransfusion system does not reduce the postoperative allogenic blood transfusion rate. At the third and fifth day postoperatively no significant differences of the hemoglobin values could be stated comparing group A with group B.
