Oxidative Stress and Total Antioxidant Status During Internal Carotid Artery Clamping with or without Shunting: An Experimental Pilot Study.

BACKGROUND The exact role of shunting during carotid endarterectomy remains controversial and unclear. The aim of this experimental study was to investigate to what degree carotid clamping may induce changes in the cerebral oxidative status and to focus on the relation of these changes with shunt insertion. MATERIAL AND METHODS Forty New-Zealand rabbits were randomized into 4 groups: group 1 classifying animals with carotid shunt and patent contralateral carotid artery; group 2 shunt and occlusion of the contralateral carotid artery; group 3 no-shunt and patent contralateral carotid artery; and group 4 no-shunt and occlusion of the contralateral carotid artery. Blood samples were collected from the ipsilateral internal jugular vein, immediately after carotid clamping (time 0), and then at 5, 10, 15, 30, and 60 minutes afterwards. Evaluation of oxidative stress was accomplished by measuring the lag-time, representing the initial phase of oxidation, rate of accumulation (RA), showing concentration of free oxygen radical and total antioxidant status (TAS) representing antioxidant composition of serum. RESULTS Lag-time was significantly different in time points 0, 30 and 60 minutes within each different group. TAS was significantly different in time points 0, 15 and 60 min and RA in time points 0, 5, 10 and 60 min within each different group. 60 minutes after carotid clamping, the rate of accumulation as well as lag-time and TAS were increased in all groups, independently of using or not shunting or the presence of contralateral occlusion. After comparing groups 1, 2 and 3 regarding lag-time, TAS and RA, we did not find statistical difference among the groups at any time point. On the contrary, groups 1, 2 and 3 did show significantly different values comparing to group 4 after 60 min of occlusion. CONCLUSIONS Our experimental work based on cerebral metabolism found a significantly higher oxidative stress in models with contralateral carotid occlusion. The use of shunt in all other models did not have any influence on oxidative response. Future human studies should focus on the relation of oxidative status and shunt insertion to determine the benefit of selective or routine shunting during CEA.

Liver tissue dissection: ultrasonic or RFA energy?

BACKGROUND: Hepatic resection is the only potential curative treatment for a wide variety of conditions. However, liver surgery is technically demanding and closely associated with a number of serious complications. New devices and techniques are currently being applied in practice, which will improve the surgical outcome. METHODS: This retrospective study compares two methods of liver parenchymal division: ultrasound energy, a modern but already widely used technique, and radio-frequency ablation (RFA), a completely novel method. The parameters investigated include the amount of blood transfused, the necessity of the Pringle maneuver, the length of time required for parenchymal division, and postoperative morbidity and mortality. The patients were divided into two groups. In one group (Group A), 15 patients underwent 17 ultrasound-assisted liver resections, in which ten metastatic tumors, six hepatomas, and one cholangiocarcinoma were resected. In Group B, 21 patients underwent 22 RFA-assisted hepatectomies in which 11 metastatic tumors, ten hepatomas, and two cholangiocarcinomas were removed. RESULTS: Thirteen patients (87%) in Group A and 11 (52%) in Group B received a transfusion, with an average of 3.5 and 1.6 units of red blood cells, respectively. The Pringle maneuver was necessary in two cases in Group A but was unnecessary in Group B. The mean length of time required for parenchymal dissection was 124 min in Group A and 93.18 min in Group B. One (6.7%) and four (19%) complications were observed in Group A and B, respectively (statistically not significant). Mortality remained zero in both groups. CONCLUSIONS: RFA energy provides a novel reliable and safe alternative that can be used exclusively or as a supplement to the older techniques. Both resection time and amount of blood transfusion were reduced in the RFA group.