Surgical patients. (A): Serum creatinine baseline values; random effect pooled d+ = −0.021 (95% CI = −0.261 to 0.219), Z (test d+ differs from 0) = −0.172, P = 0.86. (B): Serum creatinine extreme values; random effects (DerSimonian-Laird), pooled d+ = 0.068, (95% CI = −0.227 to 0.362), Z (test d+ differs from 0) = 0.45, P = 0.65. No significant differences were found between extreme values and baseline. d+ effect size = difference; DL = DerSimonian-Laird; FK = Fresenius Kabi; HES = hydroxyethyl starch; N = number of patients.