Neuroprotective Effect Of Dexmedetomidine In The Intracranial Aneurysm Surgery

Background and ObjectiveIn cerebral aneurysm surgery，blocking tumor artery or clamping tumor easily happen vascularrupture and cerebral artery spasm.The pull,oppression or hemostatic to brain all can result in differentdegree and range of cerebral ischemic damage in operation process. How to reduce brain damage, protectbrain function more and more to be value. dexmedetomidine is a new type of alpha2adrenergic receptoragonist,. In animal studies, it has been reported that the dexmedetomidine have hippocampus neuronprotective. In the animal short cerebral ischemia experiments,dexmedetomidine can prevent ischemicneurological damage.NSE（neuron specific enolase）is a kind of intracellular proteins, specific consist in nerve cellsand neuroendocrine cells, glial cells and other cranial nerve tissue contains no NSE, so it is the markenzyme of neuron damage.Under normal circumstances, NSE content of body fluids is very low.Whenbrain is ischemic anaerobic damage,neurons degeneration necrosis, nerve demyelination, disintegration,the blood brain barrier damaged,NSE leak out from the neurons into peripheral blood and cerebrospinalfluid, it can be detected concentration increases in the blood, the quantity can reflect the damage degree ofneurons.S100β proteins are found in the astrocytes, oligodendrocytes of central nervous system andperipheral nerve schwann cells, are mark protein of glial cells.When cerebral ischemia damage the glialcells, β S100protein through the intercellular fluid into the cerebrospinal fluid, through the failure of theblood brain barrier-into the blood circulation. Therefore, the blood appear S100β protein can reflect glialcell injury and death, concentration and the damage degree of the brain.In the brain,distribution of NSE and β S100protein is different, combining detection can reflect neurons and glial cell damaged inbrain.NSE and β S100protein content can reflect the degree of brain injury.This study was to observe the dexmedetomidine have has brain protection in clinic,to providetheoretical basis for clinical application.Materials and methodsNinety patients,scheduled for brain Hemangioma surgery under general anesthesisa，wererandomly divided into three groups：dexmedetomidine group1（groupD1n=30），dexmedetomidine group2（groupD2n=30），normal saline control group（group C n=30）。When three groups patients got into the operating room, some Indexes such as electrocardiogram（ECG）, heart rate （HR）,Immediate arterial blood pressure （IBP）,Pulse oxygen saturation （SpO2）and centralvenous indwelling （internal jugular vein）.Then, give sufentanil,cisatracurium besylate, etomidateanesthesia induction intubation, intraoperative anesthesia. with remifentanil, propofol,cisatracuriumbesylate maintenance anesthesia.Group D1was administered dexmedetomidine （200mg diluted to50ml）intravenously at0.5μg/kg.h after a bolus infusion at1μg/kg.h for ten min。Group D2wasadministered intravenously at0.3μg/kg.h after a bolus infusion at0.5μg/kg.h for ten min。Group C wasgiven the same normal saline。Recording heart rate、 mean arterial pressure changes at seven timepoint:In to operation home T₀、after anesthesiaT₁, beginning of operation T₂、 blocking the artery ofIntracranial aneurysm T₃, blocking the Intracranial aneurysm T₄、 cancel the blocking T₅、end of thesurgery T₆。 Recording the operation time and blocking the artery of Intracranial aneurysm time.Monitoring the concentration of S100β protein and neuron specific enolase（NSE）at five time points:,In tooperation home T₀after surgery T₆, after surgery six hours T₇, after surgery12hours T₈, after theoperation24hours T₉.All of the patients in the preoperative one day and postoperative six day use mini-mental state examination（MMSE） test cognitive function and record score.With SPSS11.5software to carry on the analysis, the results use x sto show, measurementdata is used t test, p <0.05have statistical significance.ResultsThe heart rate within the groupD1and D2at T₂、T₃、T₄、T₅、T₆time point is decreased obviously，compared with T₀、T₁time point，have statistical significance （p <0.05）, compared with C group hasstatistical significance （p <0.05）. Comparison of mean arterial pressure of three groups at different timepoints: D1, D2group have no changing significantly （p>0.05）， fluctuating significantly in group C attime point preoperative （T₀）, intraoperation（T₁、T₂、T₃、T₄、T₅）, postoperative （T₆）。 Comparing withgroupD1, D2at the each time point of intraoperation and postoperation，GroupD1, D2have obviouschanges （p <0.05）. Comparison between group D1and groupD2has no statistical significance （p>0.05）.The concentration of S100β protein of groupD1and D2at four time pointsT₆,T₇,T₈,T₉and theconcentration of neuron specific enolase（NSE）at tine point T₉compared to the group C havestatistically significant（p<0.05）。Group D1compared to D2have no statistically significant （p>0.05）. Scoreof MMSE record at postoperative six day of group D1and D2compared to the group C have nostatistically significant（p>0.05）.GroupD1compared to D2have no statistically significant （p>0.05）.Conclusions1、 Dexmedetomidine can reduce the concentration of S100β protein and NSE in theIntracranial aneurysm surgery，have neuroprotection.2、 Dexmedetomidine can maintain hemodynamic stability, maintain intracranial bloodsupply,provide the help of neuroprotective effect in the intracranial aneurysm surgery.3、MMSE test score，Dexmedetomidine group compared with control subjects have no obvious difference, that suggest dexmedetomidine has no apparent effect to postoperative cognitive dysfunction.