Effects Of General Anesthesia And Epidural Anesthesia On Early Postoperative Cognitive Function In Elderly Patients Undergoing Transurethral Resection Of Prostate

Objective To compare the effects of general anesthesia with epidural anesthesia on early postoperative cognitive function in elderly patients undergoing transurethral resection of prostate (TURP).To provide the clinical reference for the selection of anesthetic methods in this kind of patients. Meanwhile, to explore the relation between POCD and the expression of S-100β protein、 IL-6 and TNF-α in the serum, to discover the possible pathogenesis of POCD.Methods Sixty patients aged from 66 to 86 years old, American Society of Anesthesiology (ASA) Ⅰ-Ⅲ, scheduled for TURP were randomly divided into general anesthesia group and epidural anesthesia group, thirty patients in each group. Exclusion criteria:pre-existing alcoholism or drug dependence, Alzheimer’s disease (AD), Parkinson’s disease, illiteracy, Mini-mental state examination score below 20. General anesthesia group use intravenous inhalation general anesthesia. Intravenous induction before tracheal intubation and mechanical ventilation (IPPV). Keep PETCO2 within 35-45mmHg. Maintenance of anesthesia:intravenous infusion:Propofol, Remifentanil and Cisatracurium Besylate; continuous inhalation 1%～2% Sevoflurane. Epidural anesthesia group: select L2～3 or L3～4 intervertebral space to do epidural puncture. Local anesthetic:lidocaine and Ropivacaine. Keep the level of anesthesia below T8. All patients were intravenous infused phenylephrine, ephedrine, atropine or nitroglycerin if necessary to keep the fluctuation range of MAP and HR do not exceed 25% of the basic value. Keep oxygen saturation no less than 96%. During the operation use variable temperature blanket to insulate, maintain the nasopharyngeal temperature at the target 36～37℃. According to the results of blood gas analysis, correct the disorder of water and electrolyte and acid-base imbalance.50 hours after operation, use intravenous infusion of 0.03～0.04% of morphine (2ml/h) to ease pain. Monitor and record mean arterial pressure and heart rate at 10min before anesthesia(To), operation begin(T1), the end of operation(T2) and after the operation end 20 minutes(T3). Record operation time, the infusion volume, bladder irrigation fluid volume, Visual Analogue Score and serum sodium level at 1day after the surgery (T4). Extract peripheral venous blood 3ml at anesthesia before(To), the end of operation(T2) and lday after the surgery(T4). Enzyme-linked immunosorbent assay(ELISA) was used to detect the concentration of S-100 β protein、 IL-6 and TNF-a in the serum. Their cognitive function was assessed before and lday after operation using comprehensive neuro-psychological tests and scored. Calculate the difference between the score after operation and basic value. To calculate Z score of single test project and the compound Z score. Z score of two single test or compound Z≥1.96 was classified as postoperative cognitive dysfunction. Based on whether have POCD at T4, patients were divided into non-POCD group(group NP) and POCD group (group P),and IL-6. S-100β protein and TNF-a serum concentration levels were compared between the two groups. Statistical analyses were performed using the SPSS statistical software package (SPSS17.0), the quantitative data were signified by x±s, comparison of within group and between group by t test, the incidence in%, count data using chi square test, with P<0.05 considered statistically significant..Results 1. There was no significant difference in age, weight, years of education, ASA classification, MMSE basic value, operation time, the infusion volume, the prostate weight, MAP, HR during the operation, VAS score and serum sodium level at lday after the surgery between the two groups (P>0.05).2. Neuro-psychological tests score:The scores of accumulation test at T4 was significantly lower than those at To in the general anesthesia group and epidural group (both P< 0.05).| To-T4 | value of the epidural anesthesia group was significantly lower than that of the general anesthesia group (P< 0.05). In digit span-backward test, general anesthesia group had a significantly fewer digits at T4 than that at T0 (P<0.05). POCD occurred in 9 patients (15.0%,9/60). Of them,5 patients (16.7%) come from the general anesthesia group and the other four (13.3%) from the epidural anesthesia group. There was no significant difference in the incidence of POCD between the two groups (P> 0.05).3. S-100βprotein、IL-6 and TNF-a concentration:The concentrations of S-100βprotein, IL-6 and TNF-α at T2 were significantly higher than those at To in both general anesthesia group and epidural anesthesia group(all P<0.05). The concentrations of S-100 β protein, IL-6 and TNF-α at T2 were also significantly higher than those at To in both POCD subgroup and non POCD subgroup(all P< 0.05). The concentration of S-100 β protein, IL-6 and TNF-α at T2 and IL-6 at T4 in the POCD subgroup were significantly higher than those in the non-POCD subgroup (all P< 0.05).Conclusions 1. Compared with general anesthesia, epidural anesthesia cannot reduce the incidence rate of POCD in elderly patients undergoing transurethral resection of prostate, can provide a variety of choices for clinical anesthesia in such patients.2. Patients with POCD are companied with high expressions of S-100β protein, IL-6 and TNF-a, speculate that the increase of S-100 β protein, IL-6 and TNF-a in the serum of patients maybe one of mechanism for POCD occurrence.