The subgroup was part of a randomized trial in 167 patients initially allocated to continuous norepinephrine administration starting with 2 g/kg per hour combined with 1 ml/kg per hour initially and 3 ml/kg per hour crystalloid infusion after cystectomy ( norepinephrine/low volume group of 51 ) or a standard crystalloid infusion of 6 ml/kg per hour throughout surgery ( 42 controls ) .