Then Dexmedetomidine were maintained at @ microg x kg ( -@ ) x h ( -@ ) and @ microg x kg ( -@ ) x h ( -@ ) in group D@ and group D@ and were withdrawed @ min before the end of operation , the same maintained speed of normal saline was given in group C. BIS value was maintained at @-@ by adjusting the inhaled concentration of sevoflurane .