Effect of tourniquet use on activation of coagulation in total knee replacement

Total knee replacement often is performed with tourniquet application. The advantages of a dry field, including fixation, are well known, but it still is debatable if tourniquet application increases deep vein thrombosis, Mea surement of coagulation markers is a well accepted method of studying throm bogenesis activation intraoperatively and postoperatively. Twenty patients undergoing total knee replacement with subarachnoid anesthesia were assigne d randomly to two groups: tither with tourniquet application (Group I) or w ithout tourniquet application (Group II). There were no differences between patients in the two groups in terms of age, gender, diagnosis (all had ost eoarthritis), operative time, and total (intraoperative and postoperative) blood loss. Markers for thrombin generation and fibrinolysis were measured. Blood samples were drawn at four times: baseline before the operation; aft er bone cuts; after cement fixation (Group II) or 2 minutes after tournique t deflation (Group I); and 1 hour after surgery. Markers of thrombin genera tion and fibrinolysis showed a significant increase from baseline in all th e patients. In Group II these markers started to increase during surgery, w hereas in Group I the increase occurred at the end of the procedure when th e tourniquet was deflated. The total amount of thrombin generation was sign ificantly higher in Group II (without tourniquet), whereas fibrinolysis was significantly greater in Group I. Total knee replacement is accompanied by a hypercoagulative state with or without the use of a tourniquet, but it s eems to be higher when the tourniquet is not used. In addition, tourniquet application may increase fibrinolysis.