In this randomized , controlled trial , 48 patients scheduled for hip arthroplasty with spinal anesthesia were randomized into two groups : 24 patients were allocated to receive a preload of 15 mL.kg ( -1 ) of HES 130/0 .4 and 24 patients received a preload of 30 mL.kg ( -1 ) lactated Ringer solution before surgery .