Sympathectomy-mediated vasodilatation: a randomized concentration ranging study of epidural bupivacaine.

Purpose: We tested the hypothesis that the development of sympathectomy-mediated vasodilatation is dependent on the concentration rather than the dose of epidural local anesthetic administered.

Methods: Sixty subjects receiving lumbar epidural bupivacaine were randomised to one of three groups: A: 10 ml 0.5% (50 mg); B: 10 ml 0.