COMPARISON OF EXTRADURAL AND GENERAL-ANESTHESIA ON THE FIBRINOLYTIC RESPONSE TO TOTAL KNEE ARTHROPLASTY

Extradural anaesthesia is associated with lower incidences of deep vei n thrombosis after total knee arthroplasty. It is not known if the typ e of anaesthesia influences thrombogenesis or fibrinolysis during knee surgery performed under tourniquet. We studied 31 patients allocated randomly to receive either extradural or general anaesthesia for prima ry unilateral total knee arthroplasty performed under tourniquet. Radi al artery blood samples were obtained before surgery, during surgery w ith the tourniquet inflated and on deflation of the tourniquet. Plasma samples were assayed for markers of thrombin generation and fibrinoly sis. Two of the circulating indices of thrombin generation, fibrinopep tide A and thrombin-antithrombin complexes, increased to a similar deg ree in the perioperative period in both groups. Fibrinolytic activity was similar in both groups, as measured by tissue plasminogen activato r (t-PA) antigen, t-PA activity, t-PA-plasminogen activator inhibitor complexes, alpha(2)-plasmin inhibitor-plasmin complexes and D-dimer. E xtradural and general anaesthesia did not result in significant differ ences in either thrombin generation or fibrinolytic activity during to tal knee arthroplasty performed under tourniquet.