Abstract

The onset, spread, and regression of epidural anesthesia following either lidocaine hydrocarbonate with epinephrine or lidocaine hydrochloride with epinephrine were compared in two similar groups of 45 patients each. The mean duration of surgery and the mean dose of local anesthetic were comparable in the two groups. Satisfactory surgical analgesia and muscle relaxation at the operative site were achieved in 96% of patients given the hydrocarbonate and 91% of those given the hydrochloride. Both the upward spread of sensory analgesia and the speed of onset of the motor blockade were significantly faster with the hydrocarbonate. Sensory analgesia at T4 or above was achieved in approximately 90% of patients in the hydrocarbonate group compared to 80% of those in the hydrochloride group. Complete motor blockade in the lower extremities was accomplished in over 62% of the patients given the hydrocarbonate compared to 36% of those given the hydrochloride. Regression of both sensory analgesia and motor blockade was comparable in the two groups, and both lidocaine formulations were free of serious side effects.