关键词: Narcotrend, LC, 脑电功率, 术后躁动, 脑电图, 脑电频率, 右旋美托咪定

Abstract: Methods This study was performed by two kinds of classification methods. Firstly, 60 patients were assigned to dexmedetomidine group （group D, n=30） and contral group （group C, n=30）. The patients in the group D received dex with a dose of 0.5 μ g/kg after the regular introduction of general anesthesia, while those in group C were treated with equal amount of 0.9% NaCl. EEG spectrum was collected by the Narcotrend monitor during the period before patients receiving general anesthesia till 30 minutes after removal of the endotracheal tube（including the EEG of preoperative waking state ：T Base and the period from washing out to extubation：T0）. The outcomes of RASS at the moment of T1（the right time when patients were removed of the endtracheal tube），T2（10 min after T1），T3（20 min after T1），T4 （30 min after T1）. Sedation score and the EEG spectrum were compared between two groups. Secondly，according to the RASS sedation score of awakening period, all patients were grouped into two groups： Awakening period calm state group（AC；in T1，T1，T3，T4 moment RASS score all negative）and Emergence Agitation group （EA；in T1，T1，T3，T4 moment at least one RASS score positive）. By comparing the EEG in T0 moment between group AC and group EA，observe whether the change of EEG before extubation can predict emergence agitation. Results 1）The comparation of the Intraoperative vital signs of group D and group C ：Comparison of the the mean arterial pressure MAP （mmHg）；Heart rate HR （times/min）；end?tidal CO2 tension EtCO2 ；Pulse oxygen saturation SpO2 （% ）between two groups is not statistically significant difference （P>0.05）. 2） The comparation of the status of the RASS results during awakening period of group D and group C ：there was significant difference of two groups .The negative value of RASS of group D is bigger than group C at the four moment which contains T1（the moment that patients removed of the endotracheal tube），T2（10 minutes after T1），T3（20 minutes after T1），T4（30 minutes after T1）respectivily（P<0.05）. The incidence of postoperative agitation of group C is higher than group D （P>0.05）. 3） The comparation of the EEG spectrum collected by Narcotrend monitor of group D and group C ：The total Power value of EEG in patients of group D collected by Narcotrend monitor is less than that in group C at the moment of T0 and T1 ；the percentence of Delta wave in group D is larger（P<0.05）at the moment of T1；while the other EEG data have no significance difference （P>0.05）. 4） The power and the percent of β wave in the EEG during the T0 period of EA group is bigger than that of AC group, the percent of δ wave is less than that of AC group， which can be used to predict the occurrence of emergence agitation. Conclusion DEX can provide a better postoperative sedation in patients suffering LC surgery with general anesthesia. DEX can decrease the power value of EEG spectrum and increase the percent of δ wave，which maybe the electrophysiological mechanism of the inhibitory effect on emergence agitation of DEX. The EEG changes including increasing the percent of β wave and decreasing the percent of δ wave before extubation can predict the occurrence of emergence agitation.

Key words: dexmedetomidine , frequency pectrum, narcotrend , LC , emergence agitation , power spectrum, EEG