The Determination of Optimal Intramuscular Injection Time of Midazolam as a Premedication Agent for Minimizing Decrease of Serum Potassium / 대한마취과학회지

BACKGROUND: Pre-operative anxiety is known to cause an increase in plasma catecholamine levels, which, in turn, attributes to the decrease in serum K+ concentration. Midazolam is one of the most commonly used premedication agent for the purpose of anxiolysis in the pre-operative period. In this study, by measuring serum K+ concentration, we investigated the optimal intramuscular injection time for midazolam which maximally prevents the reduction of serum K+ concentration. METHODS: One hundred twenty three patients undergoing breast surgery were randomly assigned to one of 5 groups. Control group (n = 24) had no premedication. 30-minute group (n = 30), 60-minute group (n = 25), 90-minute group (n = 22) and 120-minute group (n = 22) received IM injection of midazolam (0.05 mg/kg) at 30, 60, 90, and 120 minutes before induction of anesthesia, respectively. Anxiety level, serum K+ concentrations, blood pressures and heart rates of all patients were measured at 7:00pm of the day before surgery and immediately before induction of anesthesia. RESULTS: Serum K+ concentrations of all groups showed significant decrease in the preinduction time compared with those values at 7:00 pm of the day before surgery. There were no significant changes of heart rates in all groups. Blood pressures immediately before induction of anesthesia elevated compared with those at 7"00 pm of the day before surgery in all groups. Immediately before induction of anesthesia, the K+ levels of 60-minute and 90-minute groups were higher than those of the control group. At this time, the rates of hypokalemia (K+ <3.5 mEq/L) of 60-minute and 90-minute groups were lower than those of the control group. 30-minute and 60-minute groups had significantly lower anxiety levels than the control group. CONCLUSIONS: When we consider anxiety and serum potassium levels, the optimal intramusculr injecting time of midazolam was 60 minutes before induction of anesthesia.

Effects of Prophylactic Antiemetic Combination of Dexamethasone and Ondansetron on Postoperative Nausea and Vomiting in High-risk Patients / 대한마취과학회지

BACKGROUND: In the previous study, patients at high risk for postoperative nausea and vomiting (PONV) were identified by the Korean risk model. Consecutively, we investigated whether high-risk patients based on the Korean risk model could be managed with multiple prophylactic antiemetics. METHODS: Patients scheduled for elective surgery under general anesthesia were classified in two risk groups (first group: high risk group, second group: very high risk group) by using the Korean risk model. All patients received volatile general anesthesia and antiemetic combination of dexamethasone 5 mg (after induction) and ondansetron 4 mg (before end of surgery). We investigated the incidences of PONV in the postanesthetic care unit and at ward. RESULTS: Compared with the data from our previous study, the overall incidence of PONV decreased from 52.2% to 23.1% (P< or =0.001). The incidence decreased from 47.4% to 19.4% (P< or =0.001) in the high risk group and from 61.6% to 32.2% (P< or =0.001) in the very high risk group. The relative risk reduction did not differ between two groups (59.1%:47.7%). CONCLUSIONS: Antiemetic prophylactic with combination of dexamethasone and ondansetron was equally effective in reducing the occurrence of PONV in both group patients.

In Vitro and in Vivo Comparison of Antifibirinolytic Activity of Aprotinin and Tranexamic Acid Using a Thromboelastographic Method in Rabbits / 대한마취과학회지

BACKGROUND: Aprotinin and tranexamic acid are commonly used antifibrinolytics during liver transplantation, or cardiac surgery. However, it is not clear which drug is more effective to ameliorate the fibrinolysis. The aim of the study was to investigate the antifibrinolytic effect of both drugs at previously reported blood concentration and dose. METHODS: After inducing fibrinolysis by administering recombinant tissue plasminogen activator to rabbits, we checked the in vitro and in vivo antifibrinolytic effects at previously reported blood concentration and dose, and determined the minimum antifibrinolytic blood concentration. The previously reported blood concentration was 200 KIU/ml for aprotinin and 10 mcg/ml for tranexamic acid, and the previously reported dose was 4 mg/kg bolus plus 1 mg/kg/hr infusion for aprotinin and 10 mg/kg bolus plus 1 mg/kg/hr for tranexamic acid. RESULTS: In vitro experiment, there was effective antifibrinolytic action at previously reported blood concentration of aprotinin and the minimum antifibrinolytic blood concentration was 40 KIU/ml. For tranexamic acid, there was no antifibrinolytic action at previously reported blood concentration and the minimum antifibrinolytic blood concentration was 100 mcg/ml. In vivo experiment, there was antifibrinolytic action at previously reported dose of aprotinin and the minimum antifibrinolytic dose was 60% of previously reported dose. For tranexamic acid, there was no antifibrinolytic action at previously reported dose and the minimum antifibrinolytic dose was 10 times previously reported dose. CONCLUSION: The previously reported blood concentration and dose of aprotinin were greater and those of tranexamic acid were less than the minimum antifibrinolytic blood concentration and dose.

Repeating Cardiac Arrest and One Hour of Cardiopulmonary Resuscitation due to Severe Hyperkalemia after Reperfusion during a Liver Transplantation: A case report / 대한마취과학회지

Liver transplantation still carries considerable risks even if the improvements in surgical and anesthetic techniques lead to a significant decrease in complications. Cardiac arrest during liver transplantation occurs most frequently immediately after the reperfusion due to the influx of hyperkalemic blood from donor liver into a recipient. Cardiac arrest caused by hyperkalemia shows a favorable response to cardiopulmonary resuscitation; however, prolonged cardiopulmonary resuscitation can damage the transplanted liver as well as brain and kidney resulting increased mortality and morbidity rates. The authors experienced repeating cardiac arrest and one hour cardiopulmonary resuscitation due to severe hyperkalemia (8.8 mmol/L) just after the reperfusion during cadaveric liver transplantation. Consciousness was returned 6 hours after operation and vital signs was stable. Transplanted liver well functioned although postoperative course was complicated with acute renal failure, pneumonia and pleural effusion. The patient recovered and discharged 97 days after operation.