Abstract

A combination or psoas compartment block and sciatic nerve block was performed with a total dose of 731.5 mg mepivacaine (55 ml, 133%) with epinephrine (1:600,000) in patients scheduled for orthopedic surgery on one leg. In 20 patients, arterial blood samples were collected at timed intervals over a 6-hour period to determine the mepivacaine plasma concentration. In all patients, good sensory and motor blocks were obtained and no analgesics were required during surgery. Despite the high dose of mepivacaine, the plasma concentrations stayed below 6.0 μg/ml, with one exception, although no clinical signs of local anesthetic toxicity were observed. Plasma pharmacokinetic variables of mepivacaine were as follows: C_mar 4.22 mg·l^-1 (SD, 1.28); T_max: 0.99 hours (SD, 0.76); T_½: 3.25 hours (SD, 1.12); CL 0.55 l·hour^-1·kg^-1.