Application of Predilution Plasma Exchange: A New Plasmapheresis Method for Self-Anticoagulation, in Liver Failure

For patients with severe liver failure, citrate administration during plasma exchange (PE) may be associated with accumulation and increases the risk of death in the critically ill. To reduce this risk, we created a self-anticoagulation protocol, using predilution plasma exchange (pre-PE) with exogenous plasma and the included citrate.

Severe liver failure patients who met inclusion criteria were prospectively enrolled in our study from ICUs of two hospitals. Multiple PE treatments in enrolled patients were divided into two groups; the pre-PE group and the post-dilution plasma exchange (post-PE) group, using random table method. Therefore, anticoagulation for our PE was either included citrate (4%) within exogenous donated plasma at 750 mL/h in the pre-PE or citrate (4%) infusion at 120 mL/h and donated plasma at 1,000 mL/h routinely used in the post-PE group. Parameters such as bilirubin, coagulation function, and electrolytes were measured for analysis.

A total of 13 patients were included in this study, and 46 PE treatments assigned as pre-PE, n = 22, and post-PE, n = 24. At the end of the PE, the incidence of citrate accumulation (tCa/iCa>2.5) in the pre-PE group was significantly lower than that in the post-PE group (13.6% vs. 62.5%, p < 0.001). This study showed that the clearance of bilirubin each session in the pre-PE group was 17.23% lower than that in the post-PE group (567.79 ± 155.16 µmol vs. 685.99 ± 181.03 µmol, p = 0.022). The reduction rate of bilirubin in the pre-PE group was significantly lower than that in the post-PE group (16.49 ± 5.00 µmol/L vs. 26.00 ± 10.60 µmol/L, p < 0.0001).

This new method of pre-PE has higher safety than post-PE using exogenous donated plasma and a 4% citrate infusion, although it decreases the solute clearance efficiency slightly. It is most suitable for patients with severe liver failure.