Fig. 4

Prediction of effect of TPE on norepinephrine dose by baseline lactate concentration. Shown are estimated norepinephrine (NE) doses for both the standard of care (SOC) and therapeutic plasma exchange (TPE) group stratified by different lactate concentrations at randomization. Estimated values were calculated using a triple interaction model with TPE/ SOC and time, as well as all simple interaction terms between fixed effects. The model indicated that patients with increasing baseline lactate levels experienced diminishing NE dose reductions over 24 h when under SOC, in contrast to patients under TPE which experienced sustained NE reductions across all levels of lactate (p = 0.004). At baseline lactate concentrations of 2 mmol/l, both groups showed a reduction in NE (left panel). Above 4.5 mmol/l, patients under SOC experienced no NE dose reduction, whereas NE reduction in the TPE group remained conserved (middle panel). Above 7 mmol/l, patients in the SOC group showed increasing NE doses over time, while NE reduction was conserved in the TPE group (right panel). The thresholds for baseline lactate concentration employed were chosen post hoc in order to best illustrate the continuous effect of lactate within the model