Study of Different Concentrations of Epidural Bupivacaine for the Effects on Vasodilatation and Sensory Block

This study aims to compare human subjects receiving epidural bupivacaine local anesthetic at different doses and concentrations and to assess the effect on vasodilatation (sympathectomy), sensory and motor block. The hypothesis is that the drug concentration is more important than drug dose in the determination of the extent and intensity of differential sympathetic, sensory and motor block following epidural local anesthetic.