the Effect of Tracleer on Tourniquet-associated Hypertension

Tourniquet is widely used in orthopedic surgery. However, prolonged tourniquet inflation may cause a gradual rise in blood pressure, which named as tourniquet-associated hypertension. Thus, to effectively prevent the tourniquet related hemodynamic responses is important for patients receiving limb surgery. Tracleer is an endothelin receptor antagonist indicated for the treatment of pulmonary arterial hypertension. Tracleer can also be used to treat retistant hypertension. At present trial, the investigators are going to investigate the effect of Tracleer on tourniquet-associated hypertension during total knee arthroplasty.