Effect of Dexmedetomidine on Hemodynamic Stability in Carotid Endarterectomy: Reduced Norepinephrine Use and Propofol Dosing Via Central Sympatholytic Action

1. Objective and Selection We refer to our research project as the "research project" in this information sheet. If you participate, you will be a participant.

   In this research project, we aim to investigate the effect of the medication dexmedetomidine on blood pressure during surgery on your carotid artery. We are inviting you because all individuals undergoing carotid artery surgery may participate.

2. General Information Due to your narrowing of the carotid artery, you require a planned procedure under general anesthesia. During this, your circulatory system and heart function will be continuously monitored through ongoing measurements to constantly track your condition. At the start of general anesthesia, heart rate, blood oxygen levels, and blood pressure will be monitored. Strong painkillers and anesthetic agents will then be administered for the general anesthesia. Additional medications will be given to maintain the anesthesia. Your condition will be closely and continuously monitored throughout the general anesthesia. At the end of the surgery, the anesthetic agents will be gradually reduced, allowing you to awaken from the anesthesia. In this context, we want to examine whether the additional administration of dexmedetomidine during carotid artery surgery reduces blood pressure fluctuations that may occur during such anesthesia.

   The medication dexmedetomidine is approved for the Swiss market by Swissmedic and is commonly used today in many areas of anesthesia and intensive care medicine. It is even administered to pediatric patients in anesthesia. The goal of continuous dexmedetomidine administration during surgery is twofold: to reduce the need for other anesthetic agents while simultaneously minimizing blood pressure fluctuations that may arise during different surgical phases.

   The scientific question is: Does additional administration of dexmedetomidine influence the intraoperative hemodynamic course and thus the clinical outcome after surgery? The study will be conducted over approximately 24 months at Inselspital Bern (single-center) with 44 patients. We are conducting this study in accordance with Swiss laws and all internationally recognized guidelines. The responsible cantonal ethics committee (KEK Bern, Murtenstrasse, Bern) has reviewed and approved the study. A description of this study is also available on the website of the Federal Office of Public Health: www.kofam.ch.

3. Procedure The planned surgery will be performed independently of this study. Upon the patient's arrival in the operating room, they will be randomly assigned to one of two groups. One group will serve as the control group and receive standard general anesthesia according to our current hospital guidelines. The second group will receive the standard anesthesia plus the study medication dexmedetomidine in a precisely defined dose. Group allocation will be randomized and blinded (not disclosed to participants). The number of patients in both groups will be equal. Both groups will be treated and monitored in accordance with the recommendations and standards of the Department of Anesthesia and Pain Medicine at Inselspital Bern, as well as those of the Swiss Society for Anaesthesiology and Perioperative Medicine (SSAPM). Hemodynamic and cardiac function parameters will be closely monitored and recorded for all study participants. These data will be collected by the attending anesthesiologist.

At a precisely defined time point during the surgery (achievement of "burst suppression"), administration of the study medication will be stopped, and anesthesia will be adjusted according to surgical progress. After emergence from general anesthesia, you will be immediately assessed and then transferred to the recovery unit. During your stay on the recovery unit, circulatory parameters and your neurological status will be assessed at regular intervals.

Prior to transfer to the regular ward the following day, a questionnaire regarding your neurological status will be completed, and all medications administered during your recovery unit stay will be recorded. The study will then be finished for all participating patients.