Abstract: Effects of Sedation of Dexmedetomidine in Cervical Plexus Block for Thyroid Surgery GAO bin,CHEN xuejun,LI deqiang,JI hongbo,ZHANG shoulin,GAO shunli,PENG qiuping,TIAN yingjie Baodi Clinical college of Tianjin Medical University , Tianjin301800,China Abstract Objective：To investigate the effect of sedation of dexmedetomidine (Dexmedetomidine, Dex) in cervical plexus block for thyroid surgery.Methods：Sixty patients performed unilateral thyroid gland surgery ,were divided into tow groups randomly ，group Dex (D) and group NS (N), group D 30 cases continuous intravenous infusion of Dex, group N 30 cases continuous intravenous infusion of NS before cervical plexus block。The same of loading dose 、maintain dose and time of withdrawal amount two groups. SP、DP、HR、SpO2、Ramsay、BIS were recorded after patient in the operating room at times ：10mins before nerve block (T0) ，after blocked 5 (T1), 10 (T2), 15 (T3), 30 (T4) min and the time of separating the upper pole of thyroid (T5) .Results： The level of SP, DP, HR were significantly increased every times in group N, change nosignificantly in group D.in each group compared with T0((P>0.05); group D compared with N ( P < 0.01). SpO2 were not changes in two groups. BIS and Ramsay were significantly different at T0 compared with T1, T2, T3, T4, T5 in group D (P<0.01). BIS gradually decreased compared with Group D after the block 10min. Conclusion：good effect of Sedation 、BP and HR were stable in the thyroid gland surgery under the cervical plexus nerve block coadministed with Dex. Key words cervical plexus nerve block thyroid surgery dexmedetomidine