PERITONEAL PERMEABILITY
COMPARISON OF SEVERAL SUBSTANCES
1968 Volume 59 Issue 3 Pages 222-231
Details
1968 Volume 59 Issue 3 Pages 222-231
Apparent permeability constants of peritoneum and artificial kidney twin-coil were determined by the multiple tracer method using 24NaCl, 42KCl, 14C-urea, THO and 14C-mannitol in the way previously reported. The experimental data shown in Tables 3 and 6 were obtained from 9 adult patients, consisting of 6 patients examined by 24NaCl, 42KCl, THO, and 14C-urea, and 3 by 24NaCl and 14C-mannitol, and from 3 twin-coils examined by 24NaCl, 42KCl, THO and 14C-urea.
From these data, the following conclusions were obtained.
1) The apparent permeability constants of H2O, urea, K and mannitol are in average 2.42, 1.44, 1.40 and 0.656 times as large as that of Na respectively. Those of K, Na and mannitol are in proportion to their diffusion constants in water. On the other hand, peritoneal permeability of urea and H2O is greater than expected from their diffusion constants in water.
2) On the assumption that, mannitol does not penetrate the cell-wall and that, it passes through the intercellular space of the peritoneal membrane by simple diffusion, it is considered that, H2O, urea, K and Na pass for the most part through the intercellular space of the peritoneal membrane by simple diffusionn and that a small amount of H2O and urea is transported through the peritoneal cell-wall. It is strongly suggested that, the transfer of these substances through the peritoneal membrane is carried out by “passive transport”.
3) Peritoneal clearance and dialysance of an artificial kidney can be calculated at any flow rate from apparent permeability constants of the peritoneum and twin-coil. Their relationships are shown in Fig. 5 and 6. Peritoneal clearance and dialysance of an artificial kidney increase in accordance with the increase of the flow rate, and approach their apparent permeability constants at the infinite flow rate. These maximum urea and K dialysances of an artificial kidney are about 7 times as large as those of peritoneal clearance.
4) When intermittent peritoneal dialysis is done using a liter of dialysate at a time, average 28.4 minutes are required for the inflow and outflow of the dialysate. To get maximum efficacy, it is desirbale to perform one peritoneal dialysis by an intermittent technique about 40 minutes from the beginning of inflow to the end of outflow of the dialysate.
