| Objective: The Present study was designed to investigate the effect ofDexmedetomidine on brain injury in Patients undergoing Carotid ArteryEndarterectomy.Methods: Twenty-nine consecutive Patients, including23males and6females, aged45-65yr, weighting50-85kg, undergoing Carotid ArteryEndarterectomy were enrolled in this study. The patients were randomlydivided into two groups: Control group（group C, n=14）and Dexmedetomidinegroup（group D,n=15）. On arrival in the operating suit, intravenous infusionwas carried out and the patients received oxygen at6L/min via facemask.Radial artery was punctured and cathetered under local anesthesia, formonitoring radial arterial pressure and drawing the blood samples. Routinemonitoring included radial arterial pressure, pulse oximetry （SpO2） andelectrocardiogram by fully functional anesthesia monitor. The end-tidal carbondioxide pressure（PetCO2） were monitored by Anesthetic gases monitor; Thedepth of anesthesia were monitored by Narcotrend monitor. Five minutes later,all basic data of mean arterial pressure（MAP）, heart rate（HR）, SpO2, andanesthetic depth were recorded. Anesthesia was induced with midazolam0.1-0.15mg/kg, sufentanil0.5μ g/kg, etomidale0.15-0.3mg/kg androcuronium0.6mg/kg. All Patients were infused constantly with Propofol atthe rate of2-6mg/kg/h and remifentanil at the rate of0.1-0.3μg/kg/min formaintance until the end of the operation. Rocuronium （0.1-0.15mg/kg）wasgiven intermittently in the duration of surgey. In group D,Dexmedetomidinewas continuously infused at the rate of0.5μg/kg/h from the starting of theoperation until the end. In group C,normal saline（NS） was continuouslyinfused as placebo control to the corresponding capacity to the end of theoperation. The dosage of anesthetic drugs were adjusted to maintain the depthsof anesthesia in the range of37to64.The respiratory parameters were adjusted to maintain the pressure of end-tidal cardon dioxide（PetCO2） in the range of35to45mmHg. All patients received intravenous instillation of dezocine0.1mg/kg and tropisetron hydrochloride0.1mg/kg30minutes before the endof surgery. Intraoperatively, when systolic pressure dropped up to20%orelevated up to20%of the basic value, and when heart rate（HR） was lowerthan50times per minute,or higher than100times per minute,vasoactive drugwas infused to maintain hemodynamic stability. Anesthesia recovery: whenpatients were up to the standard of extubated,the endotracheal tube wereextubated under deep anesthesia, and patients were sent to post anesthesia careunit, PACU.Then the Patients were sent back to the ward after they werecompletely conscious.The mean artery pressure（MAP）, heart rate（HR） before induction ofanesthesia （T0）, the operation starting （T1）,before cross-clamping（T2）,themoment of cross-unclamping（T3）,as well as1h after unclamping （T4）,6hafter unclamping （T5） and24h （T6），36h（T7）after unclamping were recorded.The number of Tachycardia and/or Hypertension and Bradycardia and/orHypotension were recorded. Arterial blood samples of29Patients were drawnfrom the right or left radial artery at T0, T1, T2, T3, T4, T5, T6, T7. They werecentrifuged （3000r/min,5min）, then the supernatants were extacted and storedat-80℃until analysis for S-100β and neuron specificity enolizationenzyme（NSE）by ELLISA assay. The dosage of propofol and remifentanyl,the duration of carotid artery clamping, the duration from the end of operationto extubation, the duration of PACU, the hospitalization days were recorded.The scores of Mini-Mental State Examination, MMSE Preoperative, on thefirst day Postoperative, the third and seventh day postoperative were recorded.Postoperative The survival rate for six months after the surgery were recorded.Results:1There was no significant difference among the sex, age, weight, yearsof educated, ICA stenosis, duration of cross-clamping, the duration ofextubation, the duration of PACU, and the hospitalization days,the survivalrate for six months after the surgery（p>0.05）. 2Compared with T0,in C and D group, concentrations of S-100βwerehigher at T2, T3, T4, T5,there were significant difference（p<0.05）. Comparedwith C group, concentrations of S-100βat T0, T1, T2,T3,T6, T7,there were nosignificant difference（p>0.05）, but at T4,T5, they were significant lower.there were significant difference（p<0.05）.3In C group, compared with T0,concentrations of the NSE were higherat T1, T2, T3, T4, T5, T6, T7. There were significant difference（p<0.05）. In Dgroup, compared with T0,concentrations of the NSE were higher at T1, T3, T4,T5, T6,, T7.There were significant difference（p<0.05）. Compared with C group,concentrations of NSE at T4, T5, T6, T7were significant lower （p <0.05）; andat T0, T1, T2, T3, there were no significant difference（p>0.05）.4Compared with C group, MAP were lower at T2,T3,T4, there weresignificant difference（p <0.05）, and heart rate （HR） were lower at T2,T3,T4,there were significant difference（p <0.05）. Compared with C group,thenumber of Tachycardia and/or Hypertension was fewer, there were significantdifference（p <0.05）, and there were no significant difference for the numberof Bradycardia and/or Hypotension（p>0.05）.5Compared with C group, the consumption of Propofol and redfentanylreduced in D group intraoperatively, there were significant difference（p<0.05）.6The scores of MMSE Preoperative, on the first day postoperative,thethird day and seventh day postoperative, there were no significant difference（p>0.05）. Compared with preoperative, the scores of the first daypostoperative were lower, there were significant difference（p<0.05）.Compared with the first day postoperative, the scores of the third day andseventh day postoperative were higher, there were significant difference（p<0.05）. Compared with preoperative, there were no significant difference onthe third day and seventh day postoperative（p>0.05）.Conclusions: Dexmedetomidine plays a protective role on the braininjury in patients undergoing Carotid Artery Endarterectomy, but it doesn’thave significant effect on the postoperative cognitive and the survival rate for six months after the surgery. |
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