A Study On Effect Factors Of Cerebral Oxygen Supply-Consumption Balance And Cerebral Autoregulation In Patients During Open Abdominal Surgery

Background:The incidence of perioperative neurocognitive disorders（PND）in patients undergoing non-cardiac surgery is not optimistic.Maintaining the balance of cerebral oxygen supply-consumption and controlling the mean arterial pressure（MAP）within the range of cerebral autoregulation（CA）can protect brain perfusion and reduce the incidence of PND.Although there are many studies on the balance of cerebral oxygen supply-consumption and the range of CA in the perioperative period,most of them use the cerebral oxygen saturation（regional cerebral oxygenation,rSO₂）indicator to monitor the balance of cerebral oxygen supply-consumption,and by calculating the Pearson correlation coefficient between rSO₂ and MAP to obtain the cerebral oximetry index（COx）indicator for CA range monitoring.There are limited studies on the use of tissue hemoglobin concentration index（THI）,which can also monitor the balance of brain oxygen supply-consumption,and the use of cerebral total hemoglobin reactivity index（THx）derived by calculating the pearson correlation coefficient between THI and MAP,to monitor the balance of brain oxygen supply-consumption and the range of CA.In addition,the previous literature reports that most of the research on the range of CA focused on patients undergoing cardiac surgery,and most of the intraoperative anesthesia was inhalation anesthesia,while there were relatively few studies on non-cardiac surgery patients under intravenous anesthesia.Therefore,in order to provide a clinically reference for taking corresponding brain protection measures to reduce PND as much as possible,this study aims to use rSO₂ and THI as well as their derivative indicators COx and THx to monitor the brain oxygen supply-consumption balance and CA range in patients undergoing open hepatobiliary surgery and analyze the influencing factors.Objective:To investigate the effect factors of cerebral oxygen supply-consumption balance and CA in patients during open hepatobiliary surgery.Methods:A total of 66 patients undergoing open hepatobiliary surgery under propofol Intravenous anesthesia from August 2019 to January 2020 were included.We collected general information of all patients.Patients’rSO₂,THI,MAP,arterial blood gas indexes,and cardiac index（CI）were collected real-timely from entering the operating room to the end of the operation.Then we calculated the pearson correlation coefficient of rSO₂ and MAP to obtain the COx,and calculated the pearson correlation coefficient of THI and MAP to generate the THx to further find out the upper and lower limits of the patient’s CA range.Finally,univariate analysis and multivariate linear regression analysis were used to analyze the general data,intraoperative monitoring data and blood gas indexes to screened out the effect factors for rSO₂,THI,and the upper and lower limits of the CA range defined by COx and THx.Results:The average rSO₂ of 66 patients from entering the operating room to the end of the operation was 61.73%,and the average THI was 0.85.The results of regression analysis showed that the effect factors of rSO₂ included operation time（P=0.003）,total hemoglobin concentration（P=0.001）.And the effect factors of THI included age（P<0.001）.From the operating room to the end of the operation,the lower limit of the CA range defined by COx is83±10mm Hg,and the upper limit is 97±10mm Hg.The effect factors of the upper and lower limits of CA obtained by COx included the history of hypertension（P<0.05）,intraoperative MAP（P<0.05）,Pa O₂（P<0.05）.The lower limit of CA defined by THx is 83±10mm Hg,and the upper limit is 96±10mm Hg.The effect factors of the upper and lower limits of CA obtained by THx included the history of hypertension（P<0.05）and intraoperative MAP（P<0.05）.Conclusion:Age and operation duration were the main effect factors of the balance of cerebral oxygen supply and demand,and the history of hypertension was the main effect factor of cerebral blood flow autoregulation during open hepatobiliary surgery.Therefore,for elderly patients with hypertension during long-term surgery,attention should be paid to monitoring the cerebral oxygen supply-consumption balance and CA related indicators,and corresponding brain protection measures should be taken,which was expected to reduce the damage caused by impaired cerebral perfusion.