The Relationship Between Postoperative Cognitive Dysfunction And Regional Cerebral Oxygen Saturation In Patients Undergoing Gastrointestinal Surgery

Background and Objectives:Postoperative cognitive dysfunction（POCD）is a common serious neurological complications after surgery.It influences patients’postoperative rehabilitation and quality of life,particularly in the elderly patients.However the mechanism and causes of POCD remain so complex that currently there is no effective method that could predict POCD clearly in clinical.In recent years many studies show that POCD may be closely associated with intraoperative regional cerebral oxygen saturation（regional cerebral oxygen saturation,r SO2）.The number of elderly patients suffering from gastrointestinal cancer is rising year by year,and more and more gastrointestinal surgeries are needed.However,gastrointestinal surgeries are always large-scope and combined wih great trauma,which may lead to postoperative cognitive dysfunction in elderly patients.This clinical study was to evaluate incidence and risk factors of POCD in elderly patients with gastrointestinal surgery,and to assess the value of intraoperative regional cerebral oxygen saturation monitoring in predicting the occurrence of POCD.Methods:Patients aged at least 60 years old,ASAⅠI-Ⅲ,scheduled for elective gastrointestinal surgery under general anesthesia were enrolled in the study.Five neuropsychological tests were used to test the patients’cognitive functions on 1～2 days before surgery and one week after surgery.We get severl Z scores for the results of the tests,and patients were defined as presenting POCD if his two or more Z scores were≥1.96.Postoperative delirium（POD）is tested 3 days after surgery by Confusion Assessment Method-Chinese Reversion（CAM-CR）.Record patients’demographic characteristics（including age,sex,education,height,weight,BMI,surgery,anesthesia,smoking,ASA classification,etc.）,past medical history（diabetes,hypertension,coronary heart disease,past history of stroke）.Monitor r SO2from the awaken time to the end of the surgery.Narcotrend monitor is used to keep the depth of anesthesia and temperature monitor is used to prevent intraoperative hypothermia.Relevant informations（such as surgery name,whether laparoscopic surgery,total time of surgery,intraoperative hypotension,infusion,blood transfusion,blood loss,urine output and postoperative analgesia pumps,etc.）are collected during surgery.Such informations（laboratory before and after surgery,complications during the postoperative hospital stay,postoperative hospital stay,or whether POD or POCD）.Data was analyzed by chi-square test,t test and wilconxon test to analyze the relationship between the various factors and POCD,then Logistic regression analysis of risk factors POCD.Results:54 patients were enrolled in the study,and 48 of them complete the investigation.POCD was present in 8（16.7%）patients on one week after surgery,and their postoperative hospital stay was significantly longer.Logistic regression analyses showed that second surgery,postoperative delirium and△r SO₂were independent predictors for POCD.Conclusions:POCD incidence in elderly patients accepted gastrointestinal surgery is 16.7%.POCD is closely related with patients’surgery history,postoperative delirium,and r SO₂decreasing number during surgery.Intraoperative r SO₂monitor can be used as a predictor of POCD.