Abstract
Visual evoked potentials (VEP) during thiopentone-fentanylnitrous oxide anaesthesia were studied in 15 healthy patients undergoing non-neurosurgical procedures. The VEP was recorded before and at 1 and 2 min after induction of anaesthesia with 5–6 mg · kg−1 of thiopentone. After recording the 1 and 2 min VEPs, anaesthesia was maintained with a fentanylnitrous oxideoxygen combination, and further recordings were made at 5, 10, 15 and 20 min after induction. The 1 and 2 min VEPs showed a marked decrease in the amplitudes. Latencies were increased. The amplitudes gradually returned to the control level at 15 min, while the latencies remained increased throughout the study period. In conclusion, thiopentone should be avoided during the critical period of VEP recording. Once it is given, at least 15 min should elapse before an appropriate interpretation of the VEP can be made. Thiopentonefentanylnitrous oxide anaesthesia slightly increases the latencies of the VEP. These effects should be considered in the interpretation of the VEP when thiopentone-fentanylnitrous oxide anaesthesia is used.
Résumé
Nous avons enregistré les potentiels évoqués visuels (PEV) de 15 patients anesthésiés au thiopental-fentanyl-protoxyde d’azote pendant une intervention non neurochirurgicale. Les mesures avaient lieu une et deux minutes après l’injection de 5–6 mg · kg−1 de thiopental puis sous fentanyl et protoxyde d’azote 5, 10, 15 et 20 minutes après l’induction. A une et deux minutes, les PEV avaient une période de latence prolongée et une amplitude réduite. Cette dernière revint progressivement à la normale au bout de 15 minutes mais la période de latence demeura allongée jusqu’ à la fin de l’étude. Ainsi, le thiopental interfère avec l’interprétation des PEV et cet effet dure au moins 15 minutes. L’anesthésie au thiopental-fentanyl-protoxyde d’azote prolonge aussi légèrement la période de latence des PEV. On devra tenir compte de ces effets dans l’ interprétation des PEV.
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Chi, O.Z., Ryterband, S. & Field, C. Visual evoked potentials during thiopentone-fentanylnitrous oxide anaesthesia in humans. Can J Anaesth 36, 637–640 (1989). https://doi.org/10.1007/BF03005414
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DOI: https://doi.org/10.1007/BF03005414