Effects of Four Anesthesia Methods and Tourniquet Durations on Tourniquet Induced Hypertension during Total Knee Arthroplasty

Background: A tourniquet is often used during limb surgery to minimize surgical bleeding and to keep the clear surgical field.However the tourniquet is associated with severe hemodynamic changes and tourniquet-induced hypertension.We investigated the incidences of tourniquet-induced hypertension by tourniquet duration and anesthetic methods.Methods: One hundred thirteen patients who underwent a total knee arthroplasty were assigned into four groups according to the types of anesthesia; general anesthesia (group I, n = 30), general anesthesia and intravenous adjuvants (group II, n = 30), general and epidural anesthesia (group III, n = 22), and spinal anesthesia (group IV, n = 31).Mean arterial pressure and heart rate were recorded at ward, before induction, one minute after tourniquet inflation and every 10 minutes until 60 mininutes.The extremity was exsanguinated and a tourniquet pressure of 350 mmHg (9 cm width) was applied in all groups.Results: The mean arterial pressure increased in group I and II during the tourniquet inflation period.The incidence of tourniquet-induced hypertension was higher in group I (6.7%) than other groups but there was no statistical significance among the groups.Heart rates were not changed in any groups. Conclusions:We concluded that the shorter the tourniquet time the less the occurrence of tourniquet-induced hypertension under any type of anesthesia.(Korean J Anesthesiol 2002; 42: 312∼317)