Then Dexmedetomidine were maintained at 0.2 microg x kg ( -1 ) x h ( -1 ) and 0.7 microg x kg ( -1 ) x h ( -1 ) in group D1 and group D2 and were withdrawed 5 min before the end of operation , the same maintained speed of normal saline was given in group C. BIS value was maintained at 40-60 by adjusting the inhaled concentration of sevoflurane .