The effect of volatile anesthetics on EEG, auditory evoked potentials and somatosensory evoked potentials in dogs

Abstract

We compared the changes in EEG and evoked potentials among dogs anesthetized with halothane (H), isoflurane (I) or enflurane (E). The mean frequency of EEG with H was higher than that with I and E at 1 and 2 MAC. The amplitude of the 5th wave of auditory brain stem response with H was larger than that with I and E at 2 MAC. In terms of the Pa wave of auditory middle latency response, the amplitude with H was larger than that with E at 1 MAC, and the incidence of the wave with H was higher than that with I and E at 2 MAC. The amplitudes of N2 and N3 waves of somatosensory evoked potentials with H and I tended to decrease with increasing MAC, whereas those with E increased temporarily at 1 MAC. The inhibitory effects on EEG and evoked potentials were different among three volatile anesthetics.