Depth Of Anesthesia, As Assessed By The Narcotrend Index Influence Postoperative Cognitive Dysfunction In Elderly Patients After Abdominal Surgery

Background:Aging society is an indispensable part of the progress of civilization. If the elderly population aged65and above accounted for the total population ratio reached7%or more, then the region seen as an aging society. China has entered the aging society as early as2002. With age, older people with its unique physiological characteristics become an object which a variety of diseases easily penetrated, which makes our health care and social security industry facing more challenges. How to guarantee the quality of life of the elder, how to reduce the incidence of the elder’s illness, how to improve the cure rate of the disease in elderly patients, and how to treatment of disease and the same time to detection and timely treatment toxicity, medical workers should seriously consider about these issues. Which postoperative cognitive dysfunction in elderly patients due to its specific occurrence cause anesthesiologist’s attention.POCD was first reported in the fifty’s of last century, Professor Bedfond found that some elderly patients with some cognitive obstacles such as the memory ability damage in anesthesia, and continued for several months, and some even cause permanent damage. The main manifestations of the central nervous system complications were anxiety, depression, memory loss, personality changes and take leave of one’s senses. After cardiovascular surgical operation, especially for coronary artery bypass graft surgery (CABG) in the patients with postoperative one week,33%patients had cognitive impairment, three months after operation in29%of the patients returned to normal, but there are still4%of patients with cognitive impairment suffering from postoperative inconvenience. There are other about this kind of research data shows, the incidence rate of POCD is up to50-60%a week after heart operation, after three months of rehabilitation13-20%still exists in the patients with postoperative cognitive dysfunctionIn addition to cardiovascular operation, other big operation such as bone and joint operation, surgical operation, burn and plastic operation, summarizes the research on the data of cognitive dysfunction after non cardiac operation, found in these types of operation in elderly patients with postoperative cognitive dysfunction probability is similar, these data suggest that, in elderly patients with about20%the occurrence of POCD in non cardiac operation after operation, but after three months of recovery period patient tends to heal. However, coincidentally, another part of the research results of cognitive dysfunction after non cardiac operation is different, there are still50%patients discharged after three months of POCD, only fell to30%. The main reason for this two conclusion data results in large differences in research methods are not consistent, because the cognitive function is the subjective feelings, in order to make these subjective into the objective data to facilitate studies, usually using the cognitive function assessment scale, different scale in varying degrees of difficulty, the emphasis on cognitive function test is not the same, so easily lead to the obvious differences.Age is an independent risk factor for cognitive impairment patients with postoperative, patients age, the possibility of postoperative patients with POCD more. Similarly, whether cardiovascular operation or non cardiac operation, if patients have impaired cognitive function, patients with lower levels of education before operation, preoperative anxiety or depression, even if it is a cognitive dysfunction in adult patients after surgery may also exist. In operation of the danger of sudden events such as a lot of blood or blood pressure fluctuation, intraoperative cerebral hypoperfusion and stress response in the operation, operation trauma, postoperative pain are likely to cause or aggravate postoperative cognitive dysfunction. Although the research on POCD is very extensive, researchers and doctors agree that POCD is a clinical phenomenon, any cardiac and non cardiac operation in elderly patients, we must be aware that they may have mild to moderate cognitive deficits after surgery, although not one hundred percent, but these cognitive deficits will gradually decline until it disappeared after months of recovery, but the POCD seriously affect the patient’s quality of life after surgery, prolonged hospital stay, increased costs, so we need to reduce the incidence of POCD by reasonable research.Along with the social aging process is accelerated ceaselessly, economy and the improvement of living standards, a large operation, complex operation in elderly patients also grow with each passing day, the incidence of POCD has increased. This kind of risk for POCD in elderly patients, impaired memory, orientation ability, language communication capability, severely reducing the quality of life of patients, and even delay healing patients, caused by the increase of medical expenses. Therefore the research of POCD has important clinical significance. The old I old as well as old person, young people and the young, for our medical workers, we all hope that every elderly patient can recover smoothly, settle old age, enjoy the happiness of a family union, so we attach great importance to the study of postoperative cognitive dysfunction, hope can through clinical research, laboratory testing, fully to understand the possible causes and conditions of postoperative cognitive dysfunction during anesthesia and operation, so as to guide the clinical anesthesia and operation, reduce the incidence of POCD in elderly patients, in order to improve the quality of life of elderly patients, reduce hospitalization time.As mentioned above, old age is the most directly relevant factors of POCD, in addition, there is also some other may cause an effect on cognitive function of patients with factor. Research has shown that patients have some degree of impaired cognitive function after operation are more prone to POCD, some preoperative medication such as anticholinergics atropine, reduce CNS acetylcholine (Ach) levels, and acetylcholine (Ach) involved in learning and memory, sleep, play an important role in cognitive impairment in Ach induced anesthesia and in the operation, preoperative application of anticholinergic drugs may cause postoperative cognitive dysfunction. The size and type of operation is also correlated with the presence of POCD, POCD Department of neurosurgery operation was the highest, followed by cardiovascular operation, and other operation such as Department of orthopedics operation, surgical operation has occurred POCD reports. The current study on postoperative cognitive dysfunction of the main trend in two directions, one is associated with the pathogenesis, molecular mechanism of cognitive dysfunction in elderly patients with postoperative, such as neurotransmitters, receptors, reaction channel, many of these studies involve the immune, endocrine and central nervous system. Another kind is the factors associated with the pathogenesis of POCD, such as the elderly, cardiovascular and cerebrovascular diseases, endocrine system diseases, anesthesia, operation history in pathological and physiological reaction operation etc.. The main research direction of this article is related to anesthesia depth and occurrence of postoperative cognitive dysfunction of elderly patients.At present, the judgment about the depth of anesthesia are mainly based on acquisition of EEG, waveform analysis. EEG signal is recorded by instrumentation of nerve cells in the cerebral cortex of spontaneous, rhythmic electrical activity group. Because of anesthesia is through the composite use of sedative and analgesic drug, drug to achieve the balance between the site of action effect concentration and operation of stimulus intensity of the brain, and to meet the requirements of the operation effect, in the process of cortical electrical activity affected by anesthesia drugs inhibit, performance for the amplitude, frequency change and burst suppression, therefore the acquisition and analysis of EEG changes can be used for monitoring the depth of anesthesia. The main use of the anesthesia depth monitoring index of bispectral index (Bispectral, index, BI), entropy index contains the common state entropy and SE entropy of reaction RE (Electroencephalographic Entropy Monitors, EEM), Narcotrend index (Narcotrend, index, NI), cerebral state index (cerebral state index, CSI), auditory evoked potential (Auditory evoked potential, AEP) and patient state index (Patient State Index, PSI) and a series of anesthesia depth monitoring index, experiments using Narcotrend as an indicator to judge the depth of anesthesia, and using BIS parallel control, to investigate the effect of depth of anesthesia on cognitive function in elderly patients after abdominal operation, in order to find the reasonable depth of anesthesia the.Objectivs:Narcotrend anesthesia EEG monitoring system is a new type of EEG monitoring system, the EEG in6stages and15levels as quantitative indices, such as A, BO-2, CO-2, DO-2, EO-2, FO-1. Stage A signifies awake; B signifies a shallow sedation; C signifies the routine sedation; D signifies the general anesthesia; E signifies the depth of anesthesia; F stage (level0, level1) signifies the excessive anesthesia (burst suppression), brain electrical activity gradually disappear. The purpose of this experiment was to observe the propofol remifentanil anesthesia, general anesthesia, different grades (D0, D1, D2) on postoperative cognitive and recovery effect, to find a reasonable depth of anesthesia.Methods:150patients who undergoing general surgery, ASA grade I-II grade, age above65, abdominal surgery under general anesthesia, according to PASS15.0software randomly divided into three groups A/B/C. When the patient got into the operation room, begin Narcotrend monitoring BIS monitoring. Record Narcotrend grade (NT) and index (NI) five minutes later as the basic value before surgery (time TO). Induction of anesthesia:midazolam0.05mg/kg, propofol1.0mg/kg, remifentanil2μg/Kg. When the patient consciousness disappears, Intravenous injection rocuronium0.6mg/Kg. Control patient breathing, muscle relaxants after the satisfaction after tracheal intubation for patients. Record NT, NI value intubation (time T1). Intraoperative maintained:intraoperative infusion rate of propofol to make the depth of anesthesia were maintained grades D0/D1/D2. Analgesic maintained infusion with remifentanil0.15μg/(Kg-min). Intermittent injection of cis-atracurium ammonium maintain the degree of muscle relaxation required surgery, recording the NT, NI value when incision (time T2), intraoperative1h (time T3), intraoperative2h (time T4). End of the surgery:Stop infusion of propofol remifentanil, record NT, NI value at the end of surgery. The patients were transferred to the PACU monitoring extubation, record the time when the patient awake eyes (time T5), extubation (time T6). Record heart rate, blood pressure at each time point.Evaluation of the patient’s cognitive state respectively at the day before operation, the day after operation, and the seventh day after operation, using a simple cognitive function rating scale and the Montreal Cognitive Function Scale for patient eight neuropsychological tests and record score, the results were repeated measures analysis of variance to determine postoperative cognitive dysfunction study group recommended the adoption of international POCD composite Z-score method. If the test compound Z-score is greater than1.96, or there are two individual tests Z-score greater than1.96, the patient appeared postoperative cognitive dysfunction.Results:1. General situation comparison of the three groups of patients before surgery, the difference was not statistically significant (P>0.05).2. Comparison of the three groups of patients on cognitive function score, group A POCD occurred10cases, group B POCD occurred7cases, group C POCD occurred in6cases, there is no significant difference between two or three groups.3. Comparison of the three groups of patients on analepsia and extubation time, group B is shorter than the other two groups, but the difference was not significant.4. Three groups of patients during operation to maintain the target depth of anesthesia time percentage difference operation time without statistical significance.Conclusion:In elderly patients with abdominal operation in the application of Narcotrend monitoring in general anesthesia condition, different classification has no significant effect on early postoperative cognitive function of patients. Patient in D1grade depth of anesthesia is awake and extubation early, steady bloodstream dynamics.