The Influences of Clonidine Premedication on the Bispectral Index and Hemodynamics during the Induction of Anesthesia and Endotracheal Intubation with Propofol / 대한마취과학회지

BACKGROUND: The bispectral index (BIS) has been used as an indicator of a sedative state. In this study, we investigated the influence of intravenous clonidine 2 or 3 microgram/kg on the bispectral index and cardiovascular response to anesthetic induction. METHODS: The study design is prospective, randomized and double-blind. Ninety patients scheduled to undergo elective surgery under general anesthesia were divided into 3 groups. Each group received no premedication (group 1, n = 30), clonidine 2 microgram/kg (group 2, n = 30) and clonidine 3 microgram/kg (group 3, n = 30). The sedation and responsiveness scores of the Modified Observer's Assessment of Alertness/Sedation Scale (MOAAS/S) were measured before induction and the BIS, blood pressure, and heart rate were measured at before induction, after propofol injection, and after intubation. RESULTS: The BIS was significantly lower in groups 2 and 3 than in group 1 before anesthetic induction and intubation. Mean blood pressure was significantly lower in groups 2 and 3 than in group 1 before anesthetic induction, after propofol infusion and after intubation. Heart rate was also significantly lower in groups 2 and 3 than in group 1 after intubation. The sedation score and MOAAS/S were significantly lower in groups 2 and 3 than in group 1. CONCLUSIONS: Clonidine-premedicated patients appear to maintain stable hemodynamics during anesthetic induction and intubation. The bispectral index can be objectively used in clonidine-premedicated patients when evaluating the degree of sedation.

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

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.