Super High Flux Hemodialysis at High Dialysate Flows: An Ex Vivo Assessment

Abstract

Background and objectives

The removal of cytokines by standard hemofiltration is limited. Super high flux membranes may significantly improve removal even when used in dialysis mode. We sought to measure cytokine clearance using a large surface super high-flux membrane and a standard hemodialysis setting.

Setting

ICU laboratory of a tertiary institution.

Subjects

Six healthy volunteers.

Methods

Blood form healthy volunteers was incubated for 4 hours with E. coli endotoxin to stimulate cytokine production. Cytokine containing blood was then circulated through a dialysis circuit at 3 different dialysate flow rates. Blood and dialysate were sampled for cytokine and albumin measurements and calculation of clearances.

Results

Super high-flux dialysis achieved high median cytokine clearances (IL-1 clearance of 106 ml/min, IL-6 clearance of 66.8 ml/min, IL-8 clearance of 61.7 ml/min and TNF clearance of 36.1 ml/min). Increasing dialysate flow rate from 300 to 500 ml/min did not significantly increase cytokine clearances. Albumin clearances however were between 2.7 and 5.4 ml/min.

Conclusions

Cytokine dialysis is feasible at high dialysate flow rates yielding high cytokine clearances. Albumin loss, however, is appreciable and may require separate supplementation in the clinical setting.