The effects of propofol anesthesia on transcortical electric evoked potentials in the rat

The effects of halogenated anesthetic agents on somatosensory and motor evoked potentials (MEP) have been documented previously. Intravenous anesthetic propofol has not yet been used during MEP monitoring. This study investigates the effects of propofol on transcortical MEP in rats during bolus, infusion, and recovery conditions. After baseline MEP recordings, animals received a hetastarch bolus, followed by a propofol (10 mg/kg) bolus dose. A propofol infusion (10 mg/kg/h) and a hetastarch infusion were then begun. MEP recordings were obtained after the propofol bolus, during the infusion, and after a 30-minute recovery phase. Blood pressure readings remained stable. MEP onset latency increased, and amplitude decreased. Response duration diminished. All values returned towards the baseline during recovery. Our results show that the effects of propofol on MEPs are similar to its effects on somatosensory evoked potentials. Propofol seems to be a reasonable agent for use during intraoperative MEP monitoring and should be further investigated for use during spinal cord monitoring in humans.