The Effect of Low Dose Nitroglycerin on Hepatic Blood Flow, Real-time Local Liver Perfusion and Oxygen Extraction Ratio Following the Occlusion and Reperfusion of Hepatic Blood Flow in Experimental Dogs / 대한마취과학회지

BACKGROUND: The Pringle maneuver is traditionally used during the hepatectomy to reduce the blood loss. However, there have been no studies about local liver perfusion (LLP) and oxygen extraction ratio (ERO2) following hepatic ischemia and reperfusion. In this study, the changes in hepatic blood flow (HBF), LLP, ERO2 following hepatic ischemia and reperfusion were observed. And the effects of low dose nitroglycerin (NTG) were observed too. METHODS: A total of 14 mongrel dogs were divided into two groups; control group (C, n = 7), NTG administration group (N, n = 7), NTG administration was started 5 minutes before HBF occlusion. After femoral arterial and central venous catheterization, midline abdominal incision was made. Hepatic artery (HA) and portal vein (PV) were exposed to clamp and declamp. And then doppler flowmeter probes were applied on HA and PV to measure their blood flow and a thermal diffusion microprobe was inserted in the liver parenchyme to measure LLP. RESULTS: The HA and PV blood flow, LLP, and ERO2 were not different between two groups. However, HBF more increased compared to the baseline level in N group after reperfusion. In C group, LLP did not recover after reperfusion. The LLP in N group recovered to the baseline level after reperfusion. CONCLUSIONS: In conclusion, it was observed that the HBF increased and LLP recovered to the baseline level after reperfusion by administration of low dose NTG. The use of low dose NTG is safe and effective for hepatectomy.

Effect of Small-dose Ketamine on Hemodynamic Changes during Lower Extremity Surgery Using a Tourniquet under General Anesthesia / 대한마취과학회지

BACKGORUND: A tourniquet is commonly used to achieve bloodless field in surgery of the extremities. However, use of tourniquet occasionally has been associated with intraoperative hypertension, but the mechanism of this tourniquet-induced hypertension is unknown. We investigated the effect of preoperative ketamine on tourniquet-induced changes of arterial blood pressure (BP), heart rate (HR), cardiac index (Ci), and systemic vascular resistance index (SVRi). METHODS: Twenty-two patients of ASA physical status class 1 and 2, scheduled for lower extremity surgery using a tourniquet, were randomly assigned into two groups. Anesthesia was maintained with 1.5-2.0 vol% enflurane and 50% N2O in O2 with endotracheal intubation. The changes of BP, HR, Ci, and SVRi were measured (1) at 10 minutes after induction, (2) at 10 minutes after injection of normal saline (control group) or ketamine 0.25 mg/kg, i.v. (ketamine group) before skin incision and tourniquet inflation, (3) at immediately and 5, 10, 15, 20, 30, and 40 minutes after inflation of tourniquet, and (4) immediately after deflation of tourniquet. RESULTS: During tourniquet inflation, BP and HR were not significantly changed in each group and there was no significant differences between the two groups. However, Ci decreased during inflation of the tourniquet in both groups, and it significantly decreased in the control group at the time of 5 and 40 minutes after inflation of tourniquet. SVRi significantly increased during inflation of the tourniquet, and decreased immediately after deflation of the tourniquet in the control group. CONCLUSiONS: We concluded that preoperative iV ketamine, 0.25 mg/kg can prevent tourniquet-induced hemodynamic changes in patients under general anesthesia.

Comparison between Combined Epidural-General Anesthesia and General Anesthesia for Total Hip Replacement / 대한마취과학회지

BACKGROUND: Surgical repair of a hip fracture and a total hip replacement (THR) are mostly performed in elderly patients. The overall perioerative mortality is 0.5 to 1.0%, for which one of the common causes is pulmonary embolism during the postoperative period. A number of studies have demonstrated reduction in both perioperative blood loss and incidence of postoperative thromboembolism after a total hip replacement with spinal or epidural anesthesia. However a regional technique is often inappropriate for the patient scheduled for a THR because of the long operating time, the positioning and the manipulation required during the procedure. Even though combined epidural-general anesthesia may offer advantages for the patient undergoing a THR, until now the effects of such a technique for a THR have not been reported. The aim of this study was to compare the effects of general anesthesia (GA) and combined epidural-general anesthesia (CEGA) on blood loss, incidence of postoperative thromboembolism and effective postoperative pain control on patients undergoing a THR. METHODS: Thirty cases of both GA and CEGA for a THR performed at the department of anesthesiology, Keimyung University Dongsan Hospital from Jan. to Dec. 1999 were selected. The surgical time, volume of intravenous fluid infusion during the operation, intraoperative and postoperative transfusion volume, preoperative and postoperative hemoglobin, postoperative blood loss, use of postoperative analgesics, and incidence of postoperative thromboembolism were measured. RESULTS: Surgical time, volume of intravenous fluid administration during the operation and the use of postoperative analgesics was significaltly less in the group CEGA (P < 0.05). Mean values of intraoperative and postoperative transfusion volume, differences between preoperative and postoperative hemoglobin and postoperative blood loss were less in the CEGA group than in GA group. However, the differences were not found to be statistically significant. No difference was found between the two groups in incidence of postoperative thromboembolism. CONCLUSIONS: CEGA decreases surgical time, volume of intravenous fluid administration during an operation and provides effective postoperative pain control in patients undergoing a THR. Therefore,it is suggested that CEGA offers some advantages over GA alone.

Hemodynamic Responses and Changes in Oxygen Extraction When Using Amrinone, Dobutamine and Isoproterenol in Cardiac Tamponade-Induced Dogs / 대한마취과학회지

BACKGROUND: Cardiac tamponade is most commonly treated by needle aspiration or surgical drainage. During this process, it may be necessary to temporarily improve cardiac output and to maintain peripheral perfusion by using vasoactive drugs and volume expanders. The purpose of this study is to examine the hemodynamic effect along with oxygen availability on cardiac tamponade induced dogs caused by the use of dobutamine, isoproterenol and amrinone following pentastarch infusion. METHODS: Twenty-four dogs were divided into four groups including a control group (group I), which received only pentastarch 10 ml/kg after artifical tamponade was induced. Following the administration of pentastarch, group II (n = 6) received dobutamine by dripping 10 microgram/kg/min, and then by 20 microgram/ kg/min, group III (n = 6) received isoproterenal (0.5 microgram/kg/min, 1.0 microgram/kg/min) and group IV (n = 6) received amrinone (50 microgram/kg/min, 100 microgram/kg/min). The hemodynamic parameters were measured in seven intervals: baseline, thoracotomy, tamponade, tamponade plus pentastarch, pentastarch plus dripping (1st dose), pentastarch plus drug (2nd injection = two times the 1st dose), and pericardiostomy. Arterial and mixed venous blood gas analyses were carried out in three intervals: after thoracotomy, tamponade, pentastarch plus drug (infusion). Subsequently, oxygen extraction ratios were calculated from the oxygen delivery and oxygen consumption. RESULTS: The heart rate increased significantly during the infusion of isoproterenol (P = 0.032) 1.0 microgram/kg/min in group III and also during the dobutamine infusion when the pericardiostomy (P = 0.028) was performed in group II. Compared to the control group, cardiac output increased significantly in group II from the infusion of the 1st dose and also in group III with the 2nd dose infusion but there were no significant changes in group IV. Although the average intrapericardial pressure was 0.93 mmHg in each group and was increased to 8.23 mmHg during the induced tamponade, no significant changes occurred in the groups with drug infusion. The oxygen extraction ratio fell significantly in the groupII, III and IV during the drug infusion. CONCLUSIONS: As results of this study, it was concluded that the most effective hemodynamic improvements during the induced cardiac tamponade occured in group II with pentastarch-dobutamine while the least effective combination occurred in group IV with pentastarch-amrinone.