The Effect of Low Dose Nitroglycerin on Hemodynamics and Local Liver Perfusion Following an Occlusion and Reperfusion of the Hepatic Artery and Portal Vein in Experimental Dogs / 대한마취과학회지

BACKGROUND: To reduce massive blood loss during a hepatectomy, many anesthesiologists have used the technique of low central venous pressure maintenance by administration of low dose nitroglycerin (NTG) and/or intravenous fluid reduction. However, so far there have been no studies about local liver perfusion (LLP) changes after hepatic artery (HA) or portal vein (PV) reperfusion in patients receiving nitroglycerin administration. In this study, the changes in hemodynamics and LLP following HA and PV reperfusion along with low dose (2micro gram/kg/min) NTG administration in dogs were observed. METHODS: A total of 20 mongrel dogs were divided into four groups; HA occlusion and reperfusion group (H, n = 5), NTG administration group during the reperfusion on H (H-NTG, n = 5), PV occlusion and reperfusion group (P, n = 5), NTG administration group during the reperfusion on P (P-NTG, n = 5). After femoral and pulmonary arterial catheterization, a midline abdominal incision was made. HA and PV were exposed to clamp and declamp. A thermal diffusion microprobe was inserted in the liver parenchyme to measure LLP. RESULTS: The PV blood flow was not changed after HA occlusion, but HA blood flow increased after PV occlusion. The LLP decreased after HA and PV occlusion. The LLP recovered to the baseline level in group H-NTG after HA reperfusion, but the LLP was more increased compared to the baseline level in group H. In group P, the LLP did not recover after PV reperfusion, but the LLP in group P-NTG recovered to the baseline level after PV reperfusion. CONCLUSIONS: In conclusion, it was observed that the LLP recovered to the baseline level by administration of NTG after PV reperfusion. However, the LLP did not increase after HA reperfusion by administration of low dose NTG.

The Effect of Dopamine on Hepatic Blood Flow in Rabbits Undergoing Thoracic Epidural Anesthesia / 대한마취과학회지

BACKGROUND: Infusion of pentastarch, with or without dopamine, has been used for cardiovascular support during epidural anesthesia, especially for maintaining normotension. The purpose of this study was to evaluate the effects of dopamine on hemodynamics, estimated hepatic blood flow, and the extraction ratio of indocyanine green during thoracic epidural anesthesia with the infusion of pentastarch. METHODS: Thirty healthy rabbits, weighing 2.5 - 3.5 kg, were evenly divided into three groups during thoracic epidural anesthesia; The control group received normal saline (10 ml/kg/hr), the pentastarch group received pentastarch (10 ml/kg/hr), and the dopamine group received pentastarch (10 ml/kg/hr) and a dopamine infusion (5 microgram/kg/min). Thoracic epidural block was done at T5 level with 0.4 ml/kg of 1% lidocaine. Hepatic blood flow was estimated by measuring the clearance of indocyanine green according to the constant infusion method before and 30 and 60 minutes after epidural anesthesia. The extraction ratio of indocyanine green, heart rate, mean arterial pressure, central venous pressure and splanchnic vascular resistance were also measured at the same time in the three groups. RESULTS: Heart rates, mean arterial pressures, estimated hepatic blood flow and splanchnic vascular resistance were unchanged but central venous pressure increased significantly at 30 and 60 minutes after epidural anesthesia in the dopamine group. The extraction ratio of indocyanine green remained unchanged 30 and 60 minutes after epidural anesthesia in all groups. CONCLUSIONS: Combined therapy with pentastarch and dopamine infusion can keep the cardiovascular stability, hepatic blood flow and splanchnic vascular resistance constant during thoracic epidural anesthesia in rabbits.

Study on Hepatic Injury following Occlusion of Hepatic Inflow in Rabbits / 대한마취과학회지

BACKGROUND: Portal triad clamping was first described by Pringle in 1908 as a mean of reducing bleeding from the cut surface of the liver during parenchymal resection. More recently some studies have reported that one period of portal triad clamping could be well tolerated for a longer duration, 60~90 minutes. The liver, generally, is believed to be very sensitive to anoxic damage and susceptible to ischemia and decreased hepatic energy charge results in decreasing arterial ketone body ratio (AKBR) during portal triad clamping. METHODS: In order to observe an adverse effects to liver in 30 minutes and 60 minutes of portal triad clamping on AKBR and histologic changes,rabbits were divided into thirty minutes of portal triad clamping in one group (Group I) and 60 minutes of that in the other group (Group II). RESULTS: During clamping, the mean AKBR of group I and II were 0.39 and 0.44, and decreased significantly compared with the mean AKBR (1.08 and 1.02) before clamping. Five minute after declamping, the mean AKBR of group II (0.49) was lower (P0.05). Under light microscopic examination of liver biopsy, there was no visible diffrences between two groups during clamping, 5 minutes and 30 minutes after declamping. CONCLUSIONS: It was concluded that there was no difference in hepatic energy change(AKBR) and histologic change under light microscopy after 30 minutes declamping between two groups.