A PROSPECTIVE RANDOMIZED CONTROLLED TRIAL OF POSTOPERATIVE AUTOTRANSFUSION WITH AND WITHOUT A HEPARIN BONDED CIRCUIT

Autotransfusion has been included in the routine protocol in some unit s as an effort towards blood conservation. In this study we aimed to m easure the efficacy and limitations of autotransfusion and whether a h eparin-bonded circuit had any advantage. One hundred five patients wer e randomised to one of three post-operative treatments. Group 1 (n = 3 4) was not autotransfused whereas groups 2 (n = 36) and 3 (n = 35) rec eived autotransfusion with the circuit of group 3 coated with heparin. Homologous blood and blood products were given according to strict pr otocols identical for all groups. Transfused and circulating blood was analysed for haemostatic variables and the requirement for homologous blood was recorded. Autotransfused blood contained no intact platelet s and very high levels of D-Dimers (a peptide fragment released when f ibrin is lysed) which resulted in high levels of systemic D-Dimers in patients receiving autotransfusion. Flow cytometric analysis revealed that whilst platelet glycoprotein Ib receptors were severely reduced i mmediately following surgery, there was no additional damage caused by autotransfusion. Furthermore, there was no difference in platelet agg regation, von Willebrand factor (vWF) multimetric analysis or clotting profiles between the groups. Median (interquartile range) blood loss was 898 ml (638-1195) in group 1, 853 ml (595-1348) in group 2 and 770 ml (615-1000) in group 3 (Kruskal-Wallis P = 0.46). Median transfusio n requirements were 2 units in each group, Whilst autotransfusion does not appear to compromise haemostasis, it does not reduce the requirem ent for homologous blood and heparin-bonding of the circuit has no imp act.