The propofol dosage required for anesthetic maintenance was 29 % ( with a 95 % confidence interval , 18-40 ) lower in patients given dexmedetomidine ( 2.2 [ 1.5-3 .0 ] vs 3.1 [ 2.4-4 .5 ] mg/kg/h , P = 0.005 ) , whereas the remifentanil dosage was not significantly different ( 0.16 [ 0.09-0 .17 ] vs 0.14 [ 0.13-0 .21 ] g/kg/h with P = 0.3 ) .