Controlled ultrafiltration during single-pass dialysis with the RP-6 dialyzer and evaluation of its time-dependent ultrafiltration index.

A simple and inexpensive method is described for controlling ultrafiltration when using the high flux RP-6 dialyzer. When th RP-6 is operated in the co-current mode and with single-pass dialysate delivery, (PBo-PDo) can be used to accurately and safely control ultrafiltration. Combined results from ten dialyses indicate there is a pressure-dependent concentration polarization which affects ultra-filtration as reported previously, and in addition, a time-dependent effect indicating a more complex dialyzer/blood interaction. The ultrafiltration index decreases linearly with time. The ultrafiltration can be adequately predicted by (Formula: see text).