A Kinetic Model for Peritoneal Dialysis and Its Application for Complementary Dialysis Therapy

Kinetic models have been used in both hemodialysis (HD) and peritoneal dialysis (PD) therapies. Since many different theoretical models are available, users should choose one of these models along with the purpose of their studies. In general, simple models are useful for clinical investigations as well as clinical research, while rigorous models may be useful for engineers and cannot be utilized without an aid of computers. Several pieces of commercial software that include rigorous models are available for evaluation of peritoneal permeabilities as well as for constructing prescriptions. One of these pieces was clinically evaluated and high correlations with correlation coefficients >0.98 were found between clinical and recalculated values of total Kt/V for urea, total creatinine clearances and the ultrafiltration volume. Although the overall mass transfer-area coefficients (MTAC) of the peritoneal membrane is a diffusive parameter, it may become a useful tool for predicting peritoneal ultrafiltration by defining an index for peritoneal diffusive selectivity, the ratio of MTAC for urea to that for creatinine. It is recommended to use super high-flux dialyzers in PD+HD (complementary) combined therapy because it is the opportunity in a week to remove much middle and/or large molecules greater than β(2)-microglobulin. Kinetic models are especially useful in treatments with relatively complex prescriptions such as PD+HD combined therapy, and may be a key to the further success of these modalities performed at home.