Preoperative dexmedetomidine prevents tourniquet‐induced hypertension in orthopedic operation during general anesthesia

This study was a double-blinded randomized control trial designed to investigate the hemodynamic effects of dexmedetomidine on prolonged tourniquet inflation. Thirty-seven patients scheduled for elective orthopedic surgery of the lower limb under general anesthesia were recruited. They were randomly assigned to receive intravenous dexmedetomidine (DEX, 0.5 μg/kg; n = 18) or normal saline (CON; n = 19) before tourniquet inflation. Arterial blood pressure and heart rate were recorded every 10 minutes until 60 minutes after the start of tourniquet inflation and again immediately after deflation. In the DEX group, arterial pressure was not significantly changed, but in the CON group arterial pressure was significantly increased at 40, 50, and 60 minutes after the start of tourniquet inflation. Development of more than 30% increase in arterial pressure during tourniquet inflation was more frequent in the CON group than in the DEX group. Preoperative intravenous dexmedetomidine could therefore prevent tourniquet-induced hypertension in patients undergoing general anesthesia.