| lintoductionPostoperative cognitive dysfunction has no uniform definition. POCD is generally considered a group of central nervous system complications after anesthesia and surgery, more common in elderly patients. The patients are disorder with memory, attention, learning ability, abstract thinking and orientation. Other aspects of the disorder include loss of social activities and the ability of personality, social skills and techniques changing. The process lasts several weeks or months, even a few years or a lifetime. Postoperative cognitive dysfunction (POCD) is a common complication in elderly patients after surgery. With the development of economy and society, Chinese society is entering the aging society. The patients complicated with POCD are prolonged hospitalization with expense increased and more complications.The application of EEG in the rehabilitation of elderly patients is currently under study by professor weifu lei of qilu hospital.Therefore, strengthening the research on POCD is in line with the trend of social development, and also has great social and economic significance.Diagnosis of POCD at present, are commonly used with neuropsychological methods. This method has the same difficulty. Neuropsychological tests are made for surgical patients in preoperative and postoperative. By measuring the value changing we infer whether POCD happens or not. Due to the neuropsychological test for the assessment of brain function are sufficient, solving ability, information processing speed, flexibility and memory, It is becoming current clinical studies of POCD in the most commonly used method.The pathogenesis of POCD is not clear. The mechanism and neuroinflammatory mechanisms is one of the most important theory, there are other theory including neurotransmitter and gene changing. Neuroinflammation is led by the systemic inflammatory. Systemic inflammation can increase the permeability of blood brain barrier and inflammatory mediators in the blood will directly go into the cerebrospinal fluid. Main point of view,POCD are caused in the elderly patients with cerebral degenerativing and other disorders in organs and systems.It is trigged by anesthesia and operation.IL-6 plays an important role in defense, immune and inflammatory responses in the body, and affects cell growth and differentiation of the central nervous system (CNS). IL-6 also affects brain functions, including learning and memory ability. Intracranial IL-6 expresses mainly in microglia, neurons and astrocytes, and is involved in brain injury. Normal concentration of IL-6 participates in neuron protection and repair.In contrast, higher concentration of IL-6 exacerbates the damages of microglia and neuron.These effects may be mediated by influencing synaptic plasticity and neural developmentTNF-ais a cytokine secreted by macrophages. It possesses wide bioactivity,and plays an important role in immune regulation, inflammation regulation, and neural, endocrine and many other systems. TNF-a participates in a variety of life activities including eating, sleeping,and autonomic activities. Recent investigations showed that TNF-a may also participate in learning and memory process, and exert important effects on the pathological process of POCD [10]. The possible mechanisms of TNF-a in POCD include affecting synaptic plasticity and inhibiting the growth and differentiation of neuronal processes.Dexmedetomidine is a kind of efficient, high selective alpha-2 adrenergic receptor agonist. It has a wide effect, including sedation, anti-anxiety, anti-sympathetic nerve. It may reduce the amount of anesthetic medication. Dexmedetomidine is a clinically commonly used drugs, the study found that dexmedetomidine can well reduce the amount of inflammatory mediators after surgery. Since it can inhibit the inflammatory reaction and inevitabley has some role in prevention and treatment of POCD.2 objective:2.1 To evaluate the effect of dexmedetomidine on postoperative cognitive function.2.2 To observe the effects of dexmedetomidine on inflammatory mediators after surgery.2.3 To analyze the correlation between the inflammatory mediators and the postoperative cognitive dysfunction.3 Methods:In this retrospective study,148 patients in Linyi City People’s Hospital, 2012.01-2013.06, were selected,All these patients received time-selection surgery under Ⅰ～Ⅲ grade of general anesthesia according to the grading of American Society of Anesthesiologists. No patients had history of psychosis. These cases included 75 cases of fracture surgery,36 cases of prostate removal,31 cases of gallbladder surgery, and 6 cases of radical resection of rectal carcinoma. These research subjects were divided into dexmedetomidine (Dex) group and control group.In Dex group,there were 87 cases, including 56 males and 31 females. The ages were 61-89 years (average 70.6±4.2). The body weights were 45-95 kg (average 65.8± 5.8). The educational levels of these patients included illiteracy (11), elementary education (21), secondary education (35) and above (20). In ASA grading, there were 31 cases of Grade 1,47 cases of II and 9 cases of Grade III. There were 61 cases in control group, including 38 males and 23 females. The ages were 61～92 years (average 71.4±4.9). The body weights were 47-94kg (average 66.2±5.5). The educational levels of these patients included illiteracy (8), elementary education (16), secondary education (23) and above (14). In ASA grading, there were 22 cases of Grade 1,32 cases of II and 7 cases of Grade III.Neuropsychological tests are made with mini mental scale, digit span test, digit symbol test, captivity experimental connection, verbal fluency test. In order to eliminate the learning effect, we select 10 normal cases for control group. The Z score is accepted.The method we get it is that,the score before surgery minus that of after operation, minus that of learning effects score. the difference divided by the normal population of preoperative score standard deviation, z score is, then, done. If two or more Z score are greater or equal to 1.96, the patient is agreed to have postoperative cognitive dysfunctionThree milliliter elbow vein blood is taken one day before and after surgery, before the test is done. It is staticly placed in sealed dry tube in vitro for 1H. When the blood coagulates, it is centrifuged with 2000r/min, then 1.5ml blood serum was taken. Put the serum into Eppendorf tubes. They are stored in-70 DEG C. Measure the concentration of plasma IL-6, TNF alpha according to the guidance of manufacturers ellsa reagent.4. Results:The rate of POCD forexperimental group is 9.20%, the control group 21.31%.It has statistical significance (P< 0.05) Between the two groups. For both group,the concentration of IL-6 and TNF-a surgery is significantly increased (P< 0.05) after surgery than before. Compared with the control group, The increasing of dexmedetomidine group was significantly inhibited (P< 0.05). By quartile division method, the incidence of POCD significant difference (P< 0.05) in different levels of inflammatory mediators. Pearson method is used to evaluate the relationship between two kinds of inflammatory medium relation and POCD. For IL-6,the correlation coefficient R=0.689, P=0.043;For TNF alpha R= 0.711,P=0.038.5 conclusions:5.1 dexmedetomidine can reduce the incidence of POCD in elderly patients for surgery.5.2 dexmedetomidine can significantly reduce the increase of IL-6 and TNF-alpha after surgery.5.3 There was a significant correlation between the increase of IL-6 and TNF-after operation and the increase of POCD. |
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