Relationship Between Personality Dimensions And Postoperative Cognitive Dysfunction In Elderly Patients Undergoing Gastrointestinal Surgery

Objective:To discuss the relationship between personality dimensions and postoperative cognitive dysfunction（POCD）．Methods:Sixty five elderly patients, aged65to70years old,undergoing gastrointestinal surgery under general anesthesia, were included.All patients were under general anesthesia, and without preoperative drug. Radial artery was punctured under local anesthesia, heart rate（HR）,electrocardiogram（ECG）, pluse oxygen saturation（SpO2）, bispectral index（BIS）, arterial blood pressure were monitored. Central venous waspunctured and catheterized under local anesthesia. Patients were infusedfentanyl at4μg/kg, etomidate at150~300μg/kg until BIS down to40~60, of cisatracurium were infused at0.2mg/kg. three minutes later,tube was inserted into teachea. Tidal volume was6~8ml/kg, respiratory frequency adjustment maked partial pressure of carbon dioxide in endexpiratory gas(PETCO2) was maintained at35~40mmHg. Patients were given2-3％sevoflurane inhalant and infused with remifentanil at4~8μg kg-1h-1and intermittent injection of cisatrucurium during surgery to maintain anesthetic status. BIS value was maintained between40to60during thesurgery.30minutes before the end of operation, patients was injectedfentanyl at1μg/kg, at the end of operative, all drugs were stopped. Avoid using drugs which may cause postoperative cognitive dysfunction, such as isoflurane, atropine, midazolam etc. Patients were extubated afterthe operation and returned to the ICU whose vital signs were stable. Visual analogue scale(VAS) was record at4h and24h after surgery. If VAS score≥3, patients were injected tramadol50mg.After15minutes VAS score was reappraised until VAS score was less than3. At1day b efore operative personality was assessed by Eysenck Personality Questionnaire (EPQ) and the scores in patients with different personality dimensions were recorded. At1day before operative and the7days after surgery cognitive dysfunction was assessed by neuropsychological tests. Thegeneral data of patients, complications,duration of operation and anesthesia, education, smoking history, drinking history, application of neo-adjuvant chemotherapy, postoperative delirium were recorded. All the factors were analyzed using multivariate logistic regression analysis.Results:Fifty seven patients completed tests,ten patients developedPOCD（17.86%）. The results of logistic regression analysis showed that there was no significant difference in age, sex ratio, the time of anesthesia, operation time between two group. P grade, L grade, sex, standard of culture, anemia, smoking, drinking, blood transfusion, whether application of neoadjuvant chemotherapy, delirium were no associated withrisk for POCD. E grade and N grade were the risk of POCD. Every increased of one grade in E grade and N grade meant the risk of POCDwas4.76and8.17times greater, and the regression coefficient was0.681and0.716, respectively. Logistic regression equation was Log (P)=-10.772+2.101N+1.561E. The equation was used as predictor for POCD, the Positive Predictive Value (PPV) was100%, the Negative PredictiveValue (NPV)was92.3%, the sensitivity was60%, the specificity was100%.Conclusion:The patients with emotional instability and extroversionmore easily developed POCD.