Abstract: Objective To explore the effect of transcranial doppler ultrasound (TCD) combined with neurophysiological monitoring technology sensory evoked potential(SEP) on intraoperative individualized blood pressure management, myocardial oxygen consumption and postoperative cognitive function in patients undergoing carotid endarterectomy (CEA). 
Methods One hundred and twenty elderly patients undergoing elective CEA were enrolled as research subjects, and divided into research group (n=60) and control group (n=60) according to random number table method. The control group was treated with vasoactive drugs to increase blood pressure, and the research group was guided by the combined monitoring results of TCD and SEP during the operation. Mean velocity of middle cerebral artery (Vm) values and peripheral arterial systolic pressure before anesthesia (T00), at 10 min after anesthesia (T0), at 5 min before carotid artery occlusion (T1), immediately before and after carotid artery occlusion (T2), immediately after carotid artery occlusion (T3) and at 1 h after carotid artery occlusion (T4) were collected. The intraoperative general conditions (myocardial oxygen consumption, dosage of vasoactive drugs), the incidence of postoperative cognitive dysfunction (POCD) and the results of ultrasound reexamination at 6 months after operation were compared between the two groups. 
Results The consumption of ephedrine, nicardipine and norepinephrine, myocardial oxygen consumption and the proprtion of patients developing intraoperative bradycardia in the research group were lower than those in the control group (P＜0.05). Vm and peripheral arterial systolic pressure on the surgical side of the two groups showed a downward fluctuation trend, and the fluctuation range of Vm and peripheral arterial systolic pressure in the research group was smaller than that in the control group; The difference of interaction between groups, time points, and time points between groups were statistically significant (P＜0.05). There was no significant difference in the total incidence of POCD between the two groups (P＞0.05). The levels of C-reactive protein (CRP) and malondialdehyde in the two groups increased first and then decreased, while the level of superoxide dismutase decreased first and then increased. The levels of CRP and malondialdehyde in the research group were significantly higher than those in the control group, while the level of superoxide dismutase was significantly lower than that in the control group; There were significant differences in interactions between groups, time points, and time points between groups (P＜0.05). In 60 patients in the research group, TCD monitoring indicated that 25 patients reached the shunting standard after carotid artery occlusion during operation, and 7 patients reached the shunting standard of decreased SEP amplitude simultaneously and were given shunting operation. The positive rate of TCD monitoring was higher than that of SEP monitoring (P＜0.05), and the consistency of the proportion of shunting standards by the two methods was general (Kappa=0.243, P＜0.05). The number of patients with postoperative restenosis and secondary thrombosis in the research group was significantly less than that in the control group (P＜0.05). 
Conclusion TCD combined with SEP has a high guiding value for individualized intraoperative blood pressure management in patients with CEA, which can significantly reduce intraoperative myocardial oxygen consumption and reduce the risk of postoperative adverse events. TCD has a better monitoring effect on cerebral blood flow hyperperfusion during CEA, while SEP has a higher guiding significance for the implementation of intraoperative shunting. 

Key words: carotid endarterectomy, ultrasonography, neuroelectrophysiological monitoring