Ninety patients were randomized to receive either intermittent midazolam boluses ( 1-2 mg ) with 3.6-7 .2 g/kg/h of remifentanil ( MR group ) or dexmedetomidine 0.2-0 .7 g/kg/h after a loading dose of 1 g/kg with 1.2-2 .4 g/kg/h of remifentanil ( DR group ) .