[Alternative mechanical autotransfusion. Hemofiltration vs. hemoseparation]

The effect of haemoconcentration of shed blood from operative field during vascular surgery by either centrifugation (cell separation, n = 10) or haemofiltration (n = 10) was investigated. Interest in this in-vitro-study was focused on the quality of the blood concentrated. Various parameters were measured in the patient (before onset of anaesthesia), and in the blood after suction from operative field: 1. shed blood, 2./3. after haemoseparation/-filtration. Both procedures were easy to perform but haemofiltration produced whole blood quicker than the cell-separation technique (1.2:3.0 minutes). All patients had normal parameters. Suction led to an activation of plasma coagulation and an increase of free haemoglobin and elastase. Haemoseparation in contrast to filtration led to an elimination of thrombocytes, elastase, free hemoglobin and all proteins including antithrombin III and fibrinogen; concentration of red cells was more pronounced after separation (hct 55 vs. 35%). Heparin reduction was better after separation but plasma-heparin-levels were in a tolerable range after both procedures (0.21 vs. 0.75 U/ml). None of the procedures was followed by the appearance of activated clotting factors (F XII a). The data presented demonstrate that haemofiltration may be an alternative in intra- and postoperative autotransfusion. The particular advantage of this method is the preservation of plasma proteins after concentration procedure thus avoiding the need for additional application of fresh frozen plasma in patients with significant blood loss.