Effects Of Norepinephrine And Phenylephrine On Cerebral Oxygen Saturation And Postoperative Cognitive Function During Carotid Artery Occlusion During Carotid Endarterectomy

Objective:To explore the effects of two common pressor drugs（norepinephrine and norepinephrine）on cerebral oxygen saturation and postoperative cognitive function during carotid endarterectomy.Methods:Sixty patients who underwent carotid endarterectomy for carotid artery stenosis in Affiliated Hospital of Inner Mongolia Medical University from January 2022 to January 2023were selected and randomly assigned to norepinephrine group（N group,n=30）.Deoxyadrenalin group（P group,n=30）.Patients in the two groups were routinely monitored after entering the room,general anesthesia was performed,and vasopressor was injected 1min before carotid artery occlusion.In group N,norepinephrine（NE）0.01-0.1μg/（kg.min）was intravenously pumped;In group P,phenylephrine（PE）0.1-0.6μg/（kg.min）was pumped intravenously to maintain MAP at about 20%above basic blood pressure during carotid artery occlusion.The mean arterial pressure（MAP）and heart rate（HR）were recorded before anesthesia induction（T0）,after anesthesia induction（T1）,after anesthesia induction correction（T1*）,at carotid artery occlusion（T2）,5min after carotid artery occlusion（T3）,10min after carotid artery occlusion（T4）,at carotid artery opening（T5）and 5min after awake extubation（T6）,cardiac output（CO）,stroke volume variation（SVV）,middle cerebral artery mean velocity（Vm）,bispectral index（BIS）and regional cerebral oxygen saturation（rc St O₂）;End-tidal carbon dioxide（Pet CO₂）at T1-T5;The volume of infusion,urine volume,and blood loss;Total amount of vasopressor,atropine,esmolol,and urapidil used during surgery.Mini-mental State Examination（MMSE）was used to evaluate the cognitive function of the patients 1 day before surgery,3 days,7 days,30 days and 3 months after surgery.Venous blood was collected 24 hours before operation and 24 hours after operation,and serum was separated.The contents of glial fibrillary acidic protein（GFAP）and C-reactive protein（CRP）in serum were detected.Adverse events,cardiac arrest,heart failure and all-cause mortality were recorded within 3 months.Results:1.There was no significant difference in basic data between the two groups,including age,BMI,sex composition,smoking history,preoperative diseases（diabetes,hypertension and coronary heart disease）（P>0.05）.2.During the period of carotid artery occlusion（T2-T4）,rc St O₂and Vm in group N were significantly higher than those in group P（P<0.05）.3.There was no significant difference in MMSE between the two groups at each time point（P>0.05）,but MMSE decreased significantly 3 days after operation（P<0.05）,and MMSE increased significantly 1 month and 3 months after operation in both groups（P<0.05）.4.There was no significant difference in CRP and GFAP between the two groups at each time point（P>0.05）,but the concentration of 24h CRP in both groups increased significantly after operation（P<0.05）,and the concentration of 24h GFAP decreased significantly in both groups（P<0.05）.5.There was no significant difference in adverse events between the two groups（P>0.05）.Conclusion:1.There is a good correlation between 1.TCD monitoring of middle cerebral artery blood flow and NIRS monitoring of rc St O₂,and both have the function of monitoring the risk of cerebral ischemia.2.During CEA carotid artery occlusion,intravenous infusion of norepinephrine can increase cerebral blood flow and increase rc St O₂compared with norepinephrine.3.The change trend of postoperative MMSE in the two groups was similar;the postoperative CRP increased significantly,and the decrease of cognitive function 3 days after operation may be related to inflammatory reaction;the postoperative GFAP decreased significantly,and the increase of cognitive function at 1 and 3 months after operation may be related to the improvement of cerebral blood flow.4.The incidence of adverse events of hoarseness and drinking water cough is higher in the two groups.It is suggested that the nerve monitoring catheter should be used during the operation to avoid unnecessary nerve damage caused by the operation.