[Influence of low concentrations of halogenated anesthetics on the electroretinogram and visual evoked potentials in...

During anaesthesia for neurophysiological investigations, halogen anaesthetics delivered at high concentrations altered visually evoked potentials. Low concentrations of volatile anaesthetics were proposed to avoid these alterations. Thirty young children, with visual or neurological abnormalities, were divided in two groups: the first group (n = 16), mean age of 20 months, was anaesthetized with halothane 0.5%, and the second (n = 14), mean age of 14 months, with enflurane 1.5%. Retinal action potentials (RAP) and visually evoked potentials (VEP) were obtained by computerized methods. The morphology of graphs before anaesthesia and after increasing concentrations of anaesthetics were compared. Height and latencies of the principal waves were measured. Low concentrations of halothane as well as enflurane avoided RAP and VEP disturbances. Nevertheless, no statistically significant data was obtained because of individual variations due to age, pathology and technical conditions.