Compare with propofol group , the highest score of NRS decreased ( 1.8 1.12 vs 3.1 1.24 , P < 0.05 ) , the total dosage of fentanyl significantly decreased ( 427.6 14.1 vs 658.4 27.3 g , P < 0.05 ) and recovery time became significantly shortened ( 0.3 0.02 h vs 1.1 0.3 h , P < 0.05 ) in dexmedetomidine group .