The Effects of Anaesthesia on Cerebral Oxygenation and Cognitive Function in Carotid Endarterectomy

Background: A transient deterioration of cerebral hemodynamics and oxygenation during CEE might involve both hemispheres of the brain and affects postoperative cognition. Despite some benefits of regional blocks, the majority of procedures of carotid endarterectomy (CEE) are performed under general anaesthesia. Surprisingly, the studies comparing the effects of sevoflurane and propofol on postoperative mental state in CEE are scarce and controversial. While propofol possesses some anti-inflammatory properties, volatile anesthetics can interfere with cerebral blood flow and reperfusion-ischaemia injury via the mechanism of pre- and postconditioning. The goal of this study is to assess the effects of the anesthetics on the perioperative cerebral oxygenation and cognitive functions in CEE.

Methods: The study and informed consent are approved by the Ethical Committee of the Northern State Medical University. Forty patients (males only) who are to undergo elective CEE will be included into a prospective study and randomised to two groups receiving either total intravenous anaesthesia (TIVA group, propofol + fentanyl) or the volatile induction and maintenance of anaesthesia (VIMA group, n = 20, sevoflurane + fentanyl). All patients were operated using temporary carotid bypass. Invasive arterial pressure (AP), gas exchange, and cerebral tissue oxygen saturation (SctO2, ForeSight, CAsMed, USA) over frontal region for ipsilateral (SctO2IPSI) and contralateral (SctO2CONTR) hemispheres were registered during the surgery and up to 20 hrs of the postoperative period. The cognitive changes will be assessed at 12 hrs before as well as on Days 1 and 5 after CEE by blinded investigator using Montreal Cognitive Assessment score (MoCA).

Data will be presented as median (25-75th percentiles). Intergroup comparison will be provided with Mann-Whitney U-test and correlation analysis with Spearman's coefficient (rho). P value below 0.05 was regarded as statistically significant.