Explorative age-stratified analysis demonstrated that in stratum I ( n = @ ) the clonidine group had a significantly lower consumption of fentanyl ( clonidine : @ @ g/kg/hr , placebo : @ @ g/kg/hr ; p = @ ) and midazolam ( clonidine : @ @ g/kg/hr , placebo : @ @ g/kg/hr ; p = @ ) .