Analysis of auditory brain stem response with lidocaine injection into the cerebrospinal fluid in rats.

Auditory brain stem response (ABR) was recorded in 10 rats with total spinal anesthesia induced by injection of 2% lidocaine hydrochloride into the subarachnoid space through the skull. The ABR disappeared immediately (within 4 minutes) after the injection of 13.3 to 40.0 mg/kg lidocaine. The disappearance started with the later waves of the ABR. After cessation of the injection, the ABR reappeared and recovered progressively from wave I to wave IV. The effect of lidocaine on the ABR was reversible and extended in the acoustic nerve to the midbrain.