Application of Predilution Plasma Exchange, a new plasmapheresis method for self-anticoagulation, in liver failure

Introduction: For patients with severe liver failure, citrate accumulation is prone to occur, which increases the risk of death in critically ill patients. To reduce this risk, we created a self-anticoagulation protocol, predilution plasma exchange ( pre-PE ), in which exogenous plasma is replenished into the circuit before the plasma separator. This new method uses citrate in exogenous plasma as an anticoagulant to avoid the use of additional citrate, which would reduce the occurrence of citrate accumulation during PE. We performed pre-PE in patients with liver failure to verify its effect and safety. Methods: Severe liver failure patients who met the inclusion and exclusion criteria were prospectively enrolled in our study from ICUs of two hospitals. Because patients with liver failure often need multiple PE treatments, we did not group the patients but divided the PE treatments into two groups, the pre-PE group and the postdilution PE ( post-PE ) group, by random table method. Neither citrate (4%) nor any other anticoagulant was used in pre-PE group. 4% citrate anticoagulant was used in post-PE group. Results: 13 patients were included in this experiment, and 46 cases were treated with plasma exchange. Among them, 22 cases were treated with pre-PE , and 24 cases were treated with post-PE. This study showed that the clearance of bilirubin each session in the predilution PE group was 17.23% lower than that in the postdilution PE group ( 567.79± 155.16 µmol vs. 685.99± 181.03 µmol ) . At the end of the PE, the incidence of citrate accumulation ( Catot/Caion>2.5 ) in the predilution PE group was significantly lower than that in the postdilution PE group ( 13.6% vs. 62.5%, p<0.001 ) . Conclusion: This new method of pre-PE has higher safety than traditional post-PE, although it decreases the solute clearance efficiency slightly. It is most suitable for patients with severe liver failure.