Correlation Of Postoperative Cognitive Dysfunction And Plasma B-Amyloid Protein And RSO2

1introductionPostoperative cognitive dysfunction (post operative cognitive disfunction, POCD) refers to the nervous system complications after operation anesthesia often appears, showed impaired mental disorder, anxiety, personality change and memory, the postoperative changes in personality, ability and social ability and cognitive skills called postoperative cognitive dysfunction. The incidence of early postoperative cognitive dysfunction (POCD) can reach as high as40%-50%, which adversely affects quality of life and rehabilitation of patients. The underlying pathophysiological mechanism of POCD remains unclear.Recent studies have shown that prolonged POCD increases the incidence of dementia. Some others thought that the pathological mechanism of POCD is similar to that of AD. Also, the type of operation and anesthesia, differences in genes, Central cholinergic system, β-amyloid, cholinergic system, elderly and junks may also have impact on the development of POCD.Recent studies showed that amyloid protein (β-amyloid, protein, Aβ) is one potential markers of nervous system injury and persistent inflammation. Increased brain A β may be related to cognitive deficits closely, brain Aβ aggregation or cerebrospinal fluid concentration reflected in the plasma Aβ generation increases, and vice versa, the plasma concentration of Aβ concentration can reflect the change of cerebrospinal fluid Aβ. The plasma levels of Aβ and POCD potential relationship, there may be sensitive marker of biological to predict the occurrence and continuous of POCDRecent studies show that the development of CABG patients in POCD and regional cerebral oxygen saturation (regionalcerebral oxygen saturation, rSO2) had a significant relationship. Study on the application of NIRS display, anesthesia for abdominal operation and CABG patients, and rSO2and nervous system complications, cognitive function, hospitalization time saturated extension have significant relationship.2Objective2.1To search for the risk factors leading to POCD.2.2To investigate the correlation of POCD with rSO2and Aβ2.3To investigate the predictive value of rSO2monitoring in the occurrence of POCD.2.4To search for the ideal and sensitive biochemical marker of POCD.3MethodsThis study is divided into two parts. The first part of the study is to investigate the relationship between postoperative cognitive dysfunction and plasma beta-amyloid protein level. The second part studies on the predictive value of rSO2monitoring of postoperative cognitive dysfunction.3.1Study on the relationship between postoperative cognitive dysfunction and rSO2and plasma beta amyloid levels.This study was approvaed by the ethics committee of hospital and abtained informed consent of all patients.50cases were collected in our hospital undergoing laparoscopic pancreatoduodenectomy from December2010to May2013. There were29males and21females. The span of age was40to80years old, ASA class Ⅰ to Ⅲ. They were received five groups of neuropsychological tests1day pre-operatively and on postoperative day7respectively, the following tests:Mini-mental state examination (MMSE), Digit symbol substitution test (DSST), Trail making test (part A), Verbal fluency test, and Word recognition memory tests.Before anesthesia induction (To), at the beginning of laparoscopy (Ti), and at the time of pneumoperitoneum120min (T2), pneumoperitoneum240min (T3), pneumoperitoneum480min (T4), end of pneumoperitoneum (T5) and24h after surgery, extraction of internal jugular vein blood5ml,2ml is used for blood gas analysis,3ml determination of amyloid beta protein content by using the method of ELISA.Using near infrared spectroscopy technology (near infrared spectroscopy, in NIRS) on regional cerebral oxygen saturation (regional cerebral oxygen saturation, rSO2) continuous monitoring, and the calculation of average rSO2value (rSO2), with the minimum value of rSO2maximum percentage (rS02min) and rSO2than the base value drops (rSO2%max):Narcotrend electrodes placed on the patient’s forehead, and can record data. Record the blood loss, urine volume, volume of transfusion, anesthesia time, operation time, anesthesia drug dosage.3.2rSO2monitoring for value prediction of postoperative cognitive dysfunction50patients were selected in our hospital who were required for OLV thoracic operation (lung, esophagus) from December2011to May2012. ASA class Ⅰ-Ⅲ. There were30males and20females. OLV last more than30min, preoperative cardiopulmonary function is normal. In10cases of normal people and age, gender and selected patients were matched as normal control.A battery of neuropsychological test for1days before operation and7th day after operation were enderwent respectively, the same cognitive evaluation at the same time interval control. Neuropsychological test content includes:(1) MMSE;(2) the digit span test, digit symbol test;(3);(4) tracking trail making test A;(5) vocabulary fluency test;(6) the word identification task. Learning effects were defined as mean variation of each test from baseline among control subjects. A Z score for each individual test was calculated via comparing with baseline scores and with test results1week after surgery, by subtracting the average learning effect from these changes, and dividing by the standard deviation of control group. POCD was defined as Z scores equal to or greater than1.96on at least two testsThe establishment of ECG, HR, SpO2, PetCO2and other routine monitoring were continuously monitored after the patients entered operating room. A radial artery catheter was inserted to measure invasive blood pressure and blood gas.The double lumen endotracheal was intubated under general anesthesia, fiberoptic bronchoscopy confirmed the position of the catheter.Three electrodes connected with Narcotrend(?) monitor were placed on the skin of the forehead region to record the values of Narcotrend throughout surgery. By adjusting anesthetic sevoflurane concentration or supplementary intravenous anesthetics to keep Narcotrend index between D1and E1. During anesthesia were taken during volume controlled ventilation, lung ventilation, VT8～10ml/kg, OLV, VT6～8ml/kg, respiratory ratio of1:1～2, FiO2100%. Using near infrared spectroscopy technology (NIRS) in continuous monitoring of rSO2, recorded before induction of anesthesia (T1), OLV (T2), OLV (T3) rSO2over time, and the calculation of average rSO2value (2), with the minimum value of rSO2(rSO2min) and the percentage of rSO2compared with the basic value drop (rSO2%max)-Intraoperative blood loss, urine volume, fluids input quantity were recorded routinely.4Results4.1The incidence of POCD50cases of patients with laparoscopic pancreatoduodenectomy, a total of21patients had POCD, the incidence was45.7%.50cases of single lung ventilation patients,14cases had POCD, the incidence was28%.4.2Europsychological testPOCD group patients with laparoscopic pancreatoduodenectomy, MMSE, VFT scores of postoperative7day were significantly lower than that in non POCD group (P<0.05). The POCD group,MMSE, DST scores were lower than preoperative (P <0.05), non POCD group, the test results were no significant difference than preoperative (P<0.05).One-lung ventilation patients in group POCD, MMSE, digit span (reverse) and digit symbol test scores of postoperative7day were significantly lower than the preoperative (P<0.05). MMSE and verbal fluency scores were significantly lower than non POCD group (P<0.05).4.3Comparison of rSO2Laparoscopic pancreaticoduodenectomy patients of POCD group,rSO2%max was significantly higher than that in non POCD group (P<0.05), two groups of6time points, rSO2value、rSO2、rSO2min had no significant difference; but the POCD group rSO2o/omax was significantly higher than that in non POCD group (P<0.001).The value of rSO2T1～T4in non POCD group was significantly higher than that in To (P<0.05), T5had no significant difference in rSO2value than To. POCD group Ti was significantly higher than that in To (P<0.05), T5were lower than that of To (P <0.05), but there were no significant differences between the rest of the time points and To.One-lung ventilation patients in group POCD, the rSO2value of T2and T3moment, was significantly higher than that of T1moment (P<0.05).In non POCD group, the rSO2value of T2moment was also higher than Tl. POCD group, rSO2%max was significantly higher than that in non POCD group (P<0.05). RSO2%max>10.2%may be the early warning indicators of nerve injury.4.4Beta amyloid protein levelsPOCD group of laparoscopic pancreaticoduodenectomy, postoperative24h plasma levels of A β in before induction of anesthesia (To) increased significantly (166.97±80pg/ml vs77.9±16.03pg/ml, P<0.01); but no significant changes in non POCD group at each time point of the plasma levels of A β. After24h, plasma Aβ in POCD group was significantly higher than that in non POCD group, there was statistically significant difference (166.97±80pg/ml vs70.30±21.26pg/ml, P<0.01). Postoperative24h plasma levels of Aβ in POCD group increased significantly compared with the preoperative levels (P<0.01).4.5Risk factors of POCDMultivariate analysis of variance revealed, advanced age, education level, basal temperature, rSO2%max, PaCO2, Aβ might be associated risk factors of perioperativePOCD.5Conclusions5.1The occurrence of POCD is associated with β-amyloid protein and rSO2%max-5.2Risk factors of perioperative POCD might be older, low educational level high temperature, rSO2decreased, CO2accumulation, plasma levels of amyloid beta protein higher et al.5.3Plasma beta amyloid protein may be one of POCD sensitive biochemical marker; it provides a theoretical basis for the prevention, early intervention for POCD.5.4The value of rSO2%max might have predictive value for the occurrence of POCD; rSO2monitoring may be one of the useful monitoring tools to predict the occurrence of POCD.