Abstract
Median nerve somatosensory evoked responses (MnSSERs) were recorded in nine neurologically normal adult cardiac patients before and during the administration of high-dose fentanyl. MnSSERs were recorded prior to induction and at t = 20 win and t = 45 min postinduction. Fentanyl was administered as a slow bolus (53.2 ± 9.1 μg·kg-1), followed by a continuous infusion at 10-20 μg·kg-1·hr-1 (total dose 63.6 ± 10.1 μg·kg-1).
All MnSSER waveform components remained recordable and easily identifiable during anaesthesia. The effect of fentanyl was more pronounced on cortical waveform components, leaving subcortical components largely unaffected. There was a significant increase in the latency of the cortical MnSSER at t = 20 min, e.g., for the initial negative cortical wave, N1, the latency was 21.18 ± 1.55 ms preinduction versus 22.18 ± 1.42 ms at t = 20 min. There was also a significant decrease in the amplitude of the cortical response at t = 20 min, i.e., 2.04 ± 1.30 μV preinduction versus 1.31 ± 0.74 μV at t = 20 min. However, the degree of change was quite variable (range = 0-65 per cent). No further changes occurred at t - 45 min.
The authors conclude that MnSSERs can be consistently and reliably monitored during high-dose fentanyl anaesthesia. However, fentanyl produces modest but significant changes in the MnSSER which should be taken into account lest they be ministerpreted as neurologic injury in evolution.
Résumé
Les réponses du potentiel évoqué somatosensoriel du nerf médian (MnSSERs) ont été enregistrées chez neuf patients adultes cardiaques neurologiquement normaux, avant et pendant ľadministration de fentanyl à haute dose. Les MnSSERs ont été enregistrées avant ľinduction au t = 20 minutes et au t = 45 minutes post induction. Le fentanyl a été administré en bolus lentement (53.2 ± 9.1 μg·kg-1), suivi ďune perfusion continue de 10-20 μg·kg-1·heure-1 (dose totale 63.6 ± 10.1 μg·kg-1).
Tous les composants des tracés MnSSER pouvaient être enregistrés et identifiés facilement lors de ľanesthésie. Ľeffet du fentanyl était plus prononcé sur les composantes corticales des tracés laissant les composantes sous corticales en général non affectées. Il y avait une augmentation significative dans la latence du MnSSER cortical à t = 20 minutes, par exemple, pour ľonde corticale négative initiale, N1, la latence était de 21.18 ± 1.55 ms avant ľinduction versus 22.18 ± 1.42 ms à t = 20 minutes. Il y avait aussi une diminution significative de ľamplitude de la réponse corticale à t = 20 minutes, i.e., 2.04 ± 1.30 μV avant ľinduction versus 1.31 ± 0.74 μV at t = 20 minutes. Cependant le degré de changement était assez variable (écart = 0 - 62 pour cent). Aucun autre changement n’est survenu à t = 45 minutes.
Les auteurs concluent que les MnSSERs peuvent être surveillés régulièrement et avec confiance lors ďune anesthésie au fentanyl à haute dose. Cependant le fentanyl produit des changements minimes mais significatifs dans le MnSSER qui doivent être pris en considération afin de ne pas les interpréter comme étant des lésions neurologiques en évolution.
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The opinions expressed herein are those of the authors and are not to be construed as reflecting the views of the U.S. Navy Department, the U.S. Naval Service at large or of the U.S. Department of Defense.
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Schubert, A., Drummond, J.C., Peterson, D.O. et al. The effect of high-dose fentanyl on human median nerve somatosensory-evoked responses. Can J Anaesth 34, 35–40 (1987). https://doi.org/10.1007/BF03007679
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DOI: https://doi.org/10.1007/BF03007679