[Do baseline haemoglobin-rates point to the efficacy of blood saving techniques?]

We tested the hypothesis that blood saving techniques are more effective in patients with a low baseline haemoglobin.

We analysed retrospectively 1665 total hip replacements and 848 total knee replacements. Patients were divided in three groups according to the baseline haemoglobin (Hb): Group A were patients with a Hb of more than 15 g/dl, group B between 15 g/dl and 13 g/dl and group C with a Hb of less than 13 g/dl. The blood saving techniques applied (Preoperative blood donation, isovolemic haemodilution, and mechanical autotransfusion) aimed to a high patient population which underwent surgery without transfusion of homologous blood.

The higher the baseline value of haemoglobin the higher was the patient population without homologous blood transfusion. The lower the Hb the higher was the effectiveness of blood saving techniques. In case of total hip replacement preoperative blood donation increased the patient population without homologous blood transfusion in all three groups significantly. However, in case of total knee replacement preoperative blood donation increased the patient population without homologous blood transfusion only in group B and C significantly. In both surgical procedures the combination of preoperative blood donation with other blood saving techniques did not further increase the patient population without homologous blood transfusion. In total hip replacement mechanical autotransfusion as well as isovolemic haemodilution reduced homologous transfusion in patients with low baseline haemoglobin. However, the increase was more pronounced when both techniques were combined.

From our data is derived that the likelihood of homologous blood transfusion is greater in patients with a low baseline haemoglobin. However, in case of hip arthroplasty patients with a high baseline haemoglobin also profit from blood saving techniques while in case of knee arthroplasty the efficiency of blood saving techniques in a patient population with a high baseline haemoglobin is negligible. It seems to make sense to evaluate for the different kinds of surgery those patients who profit most from the different blood saving techniques.