Differential effects of sevoflurane and propofol on an electroretinogram and visual evoked potentials

The purpose of this study was to simultaneously evaluate the effects of sevoflurane and propofol on an electroretinogram (ERG) and visual evoked potentials (VEPs). Twenty-four patients scheduled for elective surgery under general anesthesia were allocated randomly to receive either sevoflurane (group S) or propofol (group P). An ERG and VEPs were recorded in an awake state and during anesthesia with three different minimum alveolar concentrations (MAC; 0.5, 1.0, and 1.5) of sevoflurane in group S or with three different effect-site concentrations (Ce) of 2, 3, and 4 μg/ml by using a target-controlled infusion technique in group P. Sevoflurane and propofol had little effect on amplitudes of the ERG b-wave. Sevoflurane significantly attenuated the amplitudes of VEP N75-P100 at 0.5, 1.0, and 1.5 MAC. Propofol did not significantly decrease the amplitude of VEPs at Ce of 2 or 3 μg/ml but significantly decreased it at Ce of 4 μg/ml. In summary, propofol and sevoflurane at clinical concentrations had little effect on the amplitude of an ERG. Sevoflurane attenuated the amplitudes of VEPs even at low concentrations. Propofol also attenuated the amplitudes of VEPs to a lesser extent compared to sevoflurane.