• Christian Vetter, Eva R Meyer, Kathleen Seidel, David Bervini, Markus Huber, and Vladimir Krejci.
• From the Department of Anaesthesiology and Pain Medicine, Inselspital, University Hospital, University of Bern, Bern, Switzerland (CV, ERM, MH, VK), and Department of Neurosurgery, Inselspital, University Hospital, University of Bern, Bern, Switzerland (KS, DB).
• Eur J Anaesthesiol. 2024 Nov 12.

BackgroundTotal intravenous anaesthesia guided by electroencephalography and neurophysiological monitoring may be used for carotid endarterectomy. Reduction of brain metabolic demand during cross-clamping of the internal carotid artery with propofol titrated to burst suppression requires effect-site concentrations that may delay emergence and interfere with intraoperative neurophysiological monitoring.ObjectiveTo test the hypothesis that dexmedetomidine decreases the effect-site concentration of propofol required for burst-suppression in patients undergoing carotid endarterectomy.DesignRandomised controlled trial.ParticipantsPatients undergoing carotid endarterectomy.SettingUniversity Hospital of Berne, Switzerland, from October 2018 to September 2024.InterventionsPatients were randomised into a control (n = 23) and a dexmedetomidine groups (n = 22). Total intravenous anaesthesia was administered to both groups. Patients in the dexmedetomidine group received an intravenous bolus of dexmedetomidine (0.4 μg kg-1 over 10 min) before induction, followed by a continuous intravenous infusion (0.4 μg kg-1 h-1). The effect-site concentrations of propofol were titrated against frontal electroencephalography parameters. Burst suppression was induced with propofol during cross-clamping of the internal carotid artery.Outcome MeasuresThe primary outcome was the effect-site concentration of propofol required for burst-suppression. The secondary outcomes were the requirement for vasoactive substances, neurophysiological monitoring parameters, and postoperative delirium.ResultsThe effect-site concentration of propofol required for burst suppression was 4.0 μg ml-1 [3.50 to 4.90] (median [interquartile range]) in the dexmedetomidine group compared with 6.0 μg ml-1 [5.5 to 7.3] in the control group (P < 0.001). Less norepinephrine was required in the dexmedetomidine group (total 454 μg [246 to 818] compared with 1000 μg [444 to 1326] (P = 0.015) in the control group). Dexmedetomidine did not affect intraoperative neurophysiological monitoring.ConclusionCo-administration of dexmedetomidine to total intravenous anaesthesia for carotid endarterectomy decreased the effect-site concentrations of propofol required for burst suppression by 33%. The propofol-sparing effect and peripheral alpha-agonism of dexmedetomidine may explain the reduced requirement for vasopressors.Trial RegistrationClinicaltrials.gov identifier: NCT04662177.Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the European Society of Anaesthesiology.

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