Fig. 4

ROC curves for the prediction of postoperative AKI. At the threshold of 32.5 LSPU, the peak amplitude of acetylcholine (ACh) had a sensitivity of 62% and a specificity of 71% to predict postoperative AKI. In the subgroup of patients with a preoperative iontophoresis of ACh peak > 32.5 LSPU, the proportion of organ injury was 84% compared to 59% in the subgroup of patients with a smaller ACh response (p = 0.045). LTH, local thermal hyperemia