Sympatholytic and Anti-Inflammatory Effects of Ropivacaine and Bupivacaine After Infraclavicular Block in Arterio Venous Fistula Surgery

Various mechanisms have been suggested for analgesic effects of drugs used in infra-clavicular block and each has contributed to pain relief. The aim of this study was to compare the degree of sympathetic block and measure tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-1 levels before and after infra-clavicular block with ropivacaine and bupivacaine in patients undergoing arterio venous fistula (AVF) surgery. Forty-eight patients undergoing AVF surgery were randomly divided to two groups, undergoing infra-clavicular block with ropivacaine and bupivacaine. The bupivacaine group was blocked with 30 mL of 0.5% bupivacaine and in the ropivacaine group, the blockage was done with 30 mL of 0.5% ropivacaine. Infra-clavicular block was carried out by ultrasound in a vertical manner. Blood samples were taken before the block and one hour after the block to measure IL-1, IL-6, and TNF-alpha. Data were analyzed by covariance analysis and correlation t-test. T-correlation analysis showed that in both ropivacaine and bupivacaine groups, the TNF-alpha, IL-6, and IL-1 levels decreased after the block. Also, the increase in arterial diameter was significantly greater in ropivacaine group. The present study showed that peripheral block with any single drug could reduce pre-inflammatory factors. On the other hand, ropivacaine significantly increased the diameter of the artery compared to the bupivacaine group.