Study of the effects of ketamine and fentanyl on mid-latency auditory evoked potentials

ABSTRACT

The effects of ketamine and fentanyl on the mid-latency auditory evoked potentials were studied in 28 patients undergoing minor gynecological and surgical procedures. Latencies of the peaks V, Na, Pa, Nb, P1 and amplitudes of Na/Pa, Pa/Nb and Nb/P1 were measured in the awake state and 3 minutes, 6 minutes and 10 minutes after induction of ketamine for 14 patents [group 1] and after induction of fentanyl for 14 patients [group 2]. There was no significant change in peak latencies and amplitudes during anaesthesia with ketamine and with fentanyl compared to that of the awake state. Also, there was no significant change in peak latencies and amplitudes between group 1 [anaesthetised by ketamine] and group 2 [anaesthetised by fentanyl]. Therefore, the primary processing of auditory stimuli in the primary auditory cortex seemed to be preserved during general anaesthesia with ketamine or with fentanyl