Anesthesia may influence oxidative stress responses to surgical stress during surgery. We performed a prospective study to investigate the impact of anesthesia on oxidative stress responses between patients receiving ropivacaine-based epidural anesthesia and patients receiving remifentanil-based general anesthesiaPlasma levels of oxidative stress-related substances such as superoxide dismutase (SOD) and myeloperoxidase were measured during anesthesia in patients receiving ropivacaine-based epidural anesthesia (E group) and patients receiving remifentanil-based general anesthesia (R group).SOD, which catalyzes the reduction of superoxide anions to hydrogen peroxide and has anti-oxidative effects, was significantly lower in E group at the end of surgery whereas the levels of myeloperoxydase were not different between the groups. Plasma levels of adrenaline and noradrenaline were significantly higher in R group than E groups after surgery.Although activation of sympathetic nervous system was effectively inhibited by epidural anesthesia. SOD level was low in E group. Remifentanil might directly increase SOD, independent of sympathetic nervous system.
