The importance of the interstitium in peritoneal transport.

The peritoneal capillary exchange vessels are located within all the tissues which surround the peritoneal cavity and are separated from the peritoneal dialysis fluid by the tissue interstitium. The interstitium adds an additional barrier to transcapillary transport resistance and slows the diffusion of solutes from the blood to the dialysis fluid. The interstitium also alters the pressure environment of the blood capillary and has profound effects on water transport, causing fluid loss from the cavity to the body during dialysis.