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

BACKGROUND: Various mechanisms have been suggested for analgesic effects of drugs used in infra-clavicular block and each has contributed to pain relief. OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.