The effect of convection on bidirectional peritoneal solute transport: predictions from a distributed model.

A distributed model of the peritoneum has been proposed as an alternative to the standard membrane model for describing peritoneal solute transport. The effect of convection on bidirectional peritoneal solute transport is studied theoretically using the distributed model. Approximate analytical and exact numerical solutions to the distributed model yield predictions similar to those when using a membrane model of peritoneal solute transport. Difficulties in interpretation of the membrane transport parameters may arise, however, when interstitial tissue, not the capillary wall, is the dominant diffusive solute transport resistance. Under such conditions the effect of convection on peritoneal solute transport is dependent on the transport direction. Moreover, predictions from the distributed model are similar to those for a membrane model containing two transport barriers in series. Thus, both the distributed model and a membrane model containing two serial transport barriers equivalently describe the effect of convection on bidirectional peritoneal solute transport.