PERITONEAL-FLUID AND SOLUTE TRANSPORT WITH DIFFERENT POLYGLUCOSE FORMULATIONS

Objective: To study peritoneal fluid and solute transport characterist ics using different polyglucose solutions with and without the additio n of glucose. Design: Thirty-one rats were divided into three groups. A 4-hour dwell study with frequent dialysate and blood samples was per formed in each rat using 25 mL of 7.5% polyglucose solution (PG, n = 1 1), 7.5% polyglucose + 0.35% glucose solution (PG1, n = 12), or 3.75% polyglucose + 1.93% glucose solution (PG2, n = 8). Radio-labeled human albumin (RISA) was added to the solutions as an intraperitoneal volum e (IPV) marker. In addition, polyglucose degradation was evaluated ex vivo over 24 hours. Experimental Animals: Thirty-one male Sprague-Dawl ey rats (300 g) were used. Main Outcome Measures: Fluid and solute (gl ucose, urea, sodium, potassium, and total protein) transport character istics as well as changes in dialysate osmolality were evaluated. Resu lts: The IPV was higher in the PG1 and PG2 groups than in the PG group during the first 2 hours of the dwell. The IPV, in fact, decreased du ring the first hour of the dwell in the PG group. However, the net ult rafiltration at 4 hours tended to be lower in the PG2 (3.2 +/- 1.5 mL) group compared to the PG (5.1 +/- 2.3 mL) and the PG1 groups (5.2 +/- 2.1 mL) (p = 0.07), and no significant difference was found between t he PG and PGI groups. Adding glucose to the PG solution increased the RISA elimination rate (K-E, representing the fluid absorption rate fro m the peritoneal cavity): 25.5 +/- 8.2, 37.5 +/- 12.2, and 42.5 +/- 8. 9 mu L/min for the PG, PG1, and the PG2 group, respectively, p < 0.01. Dialysate osmolality (D-os) increased with the dwell time in the PG a nd PG1 groups but decreased in the PG2 group. The increase in D-os was partially due to the degradation of glucose polymer, which was suppor ted by the marked increase in osmolality over 24 hours of incubation o f PG solution with peritoneal fluid, ex vivo. The diffusive mass trans port coefficient for the investigated solutes did not differ among the three groups (except for glucose, which was significantly lower in th e PG group). The sieving coefficient for sodium was significantly high er in the PG group compared to the PG1 group (p < 0.05). Conclusion: O ur results suggest that, although there was an initial decrease in the intraperitoneal dialysate volume, significant amounts of fluid can be removed by polyglucose solution during a single 4-hour dwell in rats, despite the low osmolality of the solution. The positive fluid remova l induced by the PG solution is partially due to the lower fluid absor ption rate associated with this solution and may, to some extent, also be due to the degradation of glucose polymer within the peritoneal ca vity, resulting in increased dialysate osmolality. The addition of glu cose to the polyglucose solution does not seem to improve ultrafiltrat ion in a 4-hour dwell in the rat model. However, the peritoneal fluid absorption rate may be increased, and peritoneal transport of glucose and sodium may be altered, by adding glucose to the polyglucose soluti on.