The Effect of Bupivacaine on Blood Coagulation In Vitro under Thromboelastography / 대한마취과학회지

BACKGROUND: Deep vein thrombosis (DVT) is a common complication following major surgical procedure. In regional anesthesia with local anesthetics, deep vein thrombosis is less frequent than in general anesthesia. Several studies have advocated that local anesthetics alter the function of platelets, the stability of vascular endothelium, and the hemodynamics of the blood flow in the epidural anesthetic region. We investigate the effect of the local anesthetic bupivacaine on blood coagulation in vitro under thromboelastography (TEG). METHODS: 16 Healthy volunteers who had no history of coagulation defect and anticoagulant use were evaluated. The patients were divided into 4 groups and each group was treated with bupivacaine in the following concentrations; the lower clinical level (1 microgram/ml, B1 group), the higher clinical level (2 microgram/ml, B2 group), the systemic toxicity level (4 microgram/ml, B3 group), and a control group which was treated with normal saline. We compared the TEG parameters of each group, reaction time (R), coagulation time (K), alpha angle (alpha), maximal amplitude(MA) and fibrinolysis index (lysis 60), respectively. RESULTS: As compared with the control group, there were no significant differences in the other 3 groups, especially in maximal amplitude. CONCLUSIONS: In the clinical concentration, bupivacaine had no effect on blood coagulation under TEG. Thus in the clinical concentration of bupivacaine, DVT is more influenced by several physiologic changes which are induced by epidural anesthesia, include stability of vascular endothelium, increased blood flow, and decreased catecholamine release rather than by the effect of bupivacaine on blood per se.

A Comparative Study of the Effective Infusion Method of Propofol for Patients That Prefer to be Sedated under Brachial Plexus Block / 대한마취과학회지

BACKGROUND: Patients who are scheduled for upper extremity surgery under brachial plexus block (BPB) prefer to have no memory of the surgical procedure and some form of sedation is therefore necessary. Because of this we have tried to find an adequate infusion method for propofol that would supply better sedation and less complications. METHODS: We divided 60 patients who were scheduled for upper extremity surgery under BPB into four groups according to loading dose and following continuous infusion rate of propofol (Group 1: 0.2 mg/kg, 8 microgram/kg/min, group 2: 0.4 mg/kg, 16 microgram/kg/min, group 3: 0.6 mg/kg, 33 microgram/kg/min, group 4: 0.8 mg/kg, 50 microgram/kg/min.). We evaluated the degree of sedation, amnesia, recovery, changes of blood pressure, heart rate, and respiratory effect of each group. RESULTS: According to the sedation score, groups 3 and 4 were sedated better than groups 1, 2 (P< 0.05). But the mean arterial pressure (MAP), heart rate and respiration were more depressed and recovery time prolonged in the higher dosage groups (P< 0.05). Three patients among group 4 developed severe respiratory depression, at which time infusion of propofol was stopped. CONCLUSIONS: The ideal infusion method of propofol for effective sedation was 0.4 0.8 mg/kg of loading dosage, followed by 16 50 microgram/kg/min of continuous infusion dosage. But the more dosages of propofol that were administered, the more complications appeared, so we must use care in administering propofol as a sedation adjuvant to BPB.