The effects of anaesthesia on cerebral oxygenation and cognitive function in elective carotid endarterectomy

Kuzkov VV1, Obraztsov MY1, Ivashchenko OY1, Ivashchenko NY1, Gorenkov VM2,
Kirov MY1

1Northern State Medical University, Dept of Anaesthesiology & Intensive Care, Arkhangelsk,
Russian Federation,
2City Hospital #1 of Arkhangelsk, Dept of Surgery, Arkhangelsk, Russian Federation

Background and Goal of Study: Volatile anaesthetics interfere with cerebral blood flow and reperfusion-ischemia injury via the mechanism known as a preconditioning. A transient deterioration of local hemodynamics and oxygenation during carotid endarterectomy (CEE) might involve both hemispheres of brain and affect postoperative cognitive function. The goal of this study was to assess the effects of anaesthetics on perioperative cerebral oxygenation and cognitive functions.

Materials and Methods: Forty patients (males only; n = 40, age 63 (59–68) yrs, weight 80 (70–90) kg) who underwent elective CEE were included into a prospective study and randomized to two groups receiving either total intravenous anaesthesia (TIVA group, n = 20; 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) over frontal region for ipsilateral (SctO2IPSI) and contralateral (SctO2CONTR) hemispheres (ForeSight, USA) were registered during the surgery and up to 24 hrs of the postoperative period. The cognitive changes were assessed 12 hrs before as well as 1 and 5 days after CEE with blinded investigator using Montreal Cognitive Assessment score (MoCA).

Results and Discussion: We did not find any significant baseline differences between groups. The VIMA demonstrated reduced mean AP compared with TIVA group during the intervention, however SctO2CONTR on the primary carotid clamping was higher during sevoflurane anaesthesia (p=0.05). In contrast, we did not observe any intergroup differences in SctO2IPSI. In both groups, SctO2IPSI decreased at the clamping and unclamping of carotid artery compared with values at start. We observed better cognitive function by Day 5 after sevoflurane compared with the TIVA group: the MoCA values were 24 (20–25) pts. vs. 20 (16–23) pts., respectively, p=0.028). In contrast, the patients of the TIVA group demonstrated significant reduction of MoCA values after the intervention (p < 0.01).

Conclusion(s): In CEE, total inhalational anaesthesia with sevoflurane preserves blood flow and oxygenation of the contralateral hemisphere and is associated with improved postoperative cognition as compared with propofol anaesthesia.

Acknowledgements: we thank the personnel of the Vascular Surgery Dept., Municipal Hospital #1 of Arkhangelsk.