Perioperative alterations of the thromboelastography in patients receiving one-stage bilateral total knee arthroplasty

Background : Total knee arthroplasty is associated with activation of coagulation and fibrinolytic system in the perioperative period. The coagulation and fibrinolytic activation in one-stage bilateral total knee arthroplasty has not been described before. Thromboelastography is a real-time aid in the monitoring of coagulation and is clinically valuable in the evaluation of whole blood hemostasis. We evaluated the coagulation and fibrinolysis system activation during and after one-stage bilateral total knee arthroplasty by thromboelastography. Methods : Twenty patients, ASA class I-II, undergoing one-stage bilateral total knee arthroplasty were included in this study. All patients received continuous spinal anesthesia with isobaric 0.2% bupivacaine. Arterial blood samples were obtained for thromboelastography in the following sequences: (1) after induction of anesthesia (baseline), (2) 20 min after releasing tourniquet of the first leg, (3) 20 min after releasing tourniquet of the second leg, (4) 2 h postoperatively, (5) 24 h postoperatively. Results : There was a significant shortening of reaction time (R value) after deflation of the first leg tourniquet, and a further decrease of R value after deflation of the second leg tourniquet and two hours postoperatively. The perioperative change of coagulation time was similar to that of R value. The maximum amplitude decreased after releasing tourniquet of the second leg and two hours postoperatively. Conclusion : The activation of coagulation, as monitored by thromboelastography, is predominant in one-stage bilateral total knee arthroplasty after releasing tourniquet of the second leg and returns to baseline 24 h postoperatively.