Fig. 3

Comparisons among receiver-operating characteristic curves. Panel a: Comparison of receiver-operating characteristic (ROC) curves between initial lactate, maximum lactate and normalized lactate load in all included patients. The AUC of normalized lactate load was significantly greater than the initial lactate and maximum lactate (all p <  0.001). There was no difference between initial lactate and maximum lactate (p = 0.207). Panel b: Comparison of ROC in patients with a maximum lactate ≥4 mmol/L. The AUC of normalized lactate load was significantly greater than both initial lactate and maximum lactate (p <  0.001 and p = 0.005, respectively). There was no difference between initial lactate and maximum lactate (p = 0.124)