Compared with placebo , low-dose dopamine had no significant effect on 72-hour cumulative urine volume ( dopamine , 8524 mL ; 95 % CI , 7917-9131 vs placebo , 8296 mL ; 95 % CI , 7762-8830 ; difference , 229 mL ; 95 % CI , -714 to 1171 mL ; P = .59 ) or on the change in cystatin C level ( dopamine , 0.12 mg/L ; 95 % CI , 0.06-0 .18 vs placebo , 0.11 mg/L ; 95 % CI , 0.06-0 .16 ; difference , 0.01 ; 95 % CI , -0.08 to 0.10 ; P = .72 ) .