Effect of Alternative Osmotic Agents on Peritoneal Transport

Waniewski, Jacek; Weryński, Andrzej; Heimbürger, Olof; Park, Min Sun; Lindholm, Bengt

doi:10.1159/000170121

Cited by 30 publications

(17 citation statements)

References 15 publications

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“…Therefore, it cannot be excluded that active transport of glucose into cells and utilization of glucose mediated by insulin in the liver [30] may influence the transport characteristics. The low values of S| and Sm found in the rat studies were also dif ferent from the values of Sm close to 0.5 which were estimated for the glucose transport from blood to dialysate in clinical studies with alternative osmotic agents [19].…”

Section: Discussioncontrasting

confidence: 77%

Sieving Coefficients for Small Solutes during Experimental Peritoneal Dialysis in Rats

et al. 1995

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A single 4-hour experimental peritoneal dialysis was performed in 6 normal Sprague-Dawley rats to investigate sieving coefficients (S) for small solutes during peritoneal dialysis. A modified 3.86% Dianeal solution with approximately the same concentrations of urea, sodium, and potassium as in the rat plasma (isochratic solution) was used to avoid diffusion of investigated solutes and to achieve sufficient ultrafiltration. As a control, a 4-hour peritoneal dialysis in 7 normal Sprague-Dawley rats was performed using the conventional 3.86% Dianeal solution. The infusion volume was 30 ml. A dilution of radioiodinated serum albumin was used to determine the intraperitoneal dialysate volume. S was calculated (1) from the mass and volume balances for the initial 30 min of the exchange with the isochratic solution (S_I, isochratic method) and (2) by using a membrane model based on the thermodynamic theory of mass transport (Sm)· The diffusive mass transport coefficient K_BD for the solutes investigated was estimated using the membrane model. The S_I values for urea, sodium, and potassium were similar with the isochratic solution. For urea and sodium, the S values were within the physiological range 0-1 whereas the S values for glucose were close to 0 and for potassium were negative. S_M for glucose, urea, and sodium using the conventional solution did not differ from the values obtained with the isochratic solution; however, S_M for potassium was significantly lower than with the isochratic solution. S_I and S_M for potassium and sodium were correlated. The K_BD values for glucose, urea, and sodium using the isochratic solution did not differ from the values obtained with the conventional solution, whereas the K_BD values for potassium were significantly higher with the isochratic solution as compared with the conventional solution. We conclude that the net sieving coefficients S_I and S_M for urea and sodium were lower than unity in the rats dialyzed with the two solutions and did not differ from the previously reported S values measured in continuous ambulatory peritoneal dialysis patients with the isochratic solution. However, the transport of potassium was abnormal with the isochratic solution, suggesting mechanisms other than passive diffusive and convective potassium transport.

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Section: Discussioncontrasting

confidence: 77%

Sieving Coefficients for Small Solutes during Experimental Peritoneal Dialysis in Rats

et al. 1995

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“…In previous studies on this subject, equilibration patterns between dialysate and plasma levels of urea, creatinine, and potassium were similar for glucose and glycerol solutions — De Paepe et al (15), Lindholm et al (16), and Waniewski et al (17) — although Heaton et al . (14) found decreased equilibration rates for small solutes.…”

Section: Discussionmentioning

confidence: 74%

Peritoneal Transport Characteristics with Glycerol-Based Dialysate in Peritoneal Dialysis

et al. 2000

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Background Glycerol is a low molecular weight solute (MW 92 D) that can be used as an osmotic agent in continuous ambulatory peritoneal dialysis (CAPD). Due to its low molecular weight, the osmotic gradient disappears rapidly. Despite the higher osmolality at the beginning of a dwell, ultrafiltration has been found to be lower for glycerol compared to glucose (MW 180 D) when equimolar concentrations are used. Previous studies have shown glycerol to be safe for long-term use, but some discrepancies have been reported in small solute transport and protein loss. Objective To assess permeability characteristics for a 1.4% glycerol dialysis solution compared to 1.36% glucose. Design Two standardized peritoneal permeability analyses (SPA), one using 1.4% glycerol and the other using 1.36% glucose, in random order, were performed within a span of 2 weeks in 10 stable CAPD patients. The length of the study dwell was 4 hours. Fluid kinetics and solute transport were calculated and signs of cell damage were compared for the two solutions. Setting Peritoneal dialysis unit in the Academic Medical Center, Amsterdam. Results Median values for the 1.4% glycerol SPA were as follows: net ultrafiltration 251 mL, which was higher than that for 1.36% glucose (12 mL, p < 0.01); transcapillary ultrafiltration rate 2.12 mL/min, which was higher than that for glucose (1.52 mL/min, p = 0.01); and effective lymphatic absorption rate 1.01 mL/min, which was not different from the glucose-based solution. Calculation of peritoneal reflection coefficients for glycerol and glucose showed lower values for glycerol compared to glucose (0.03 vs 0.04, calculated with both the convection and the diffusion models). A marked dip in dialysate-to-plasma ratio for sodium was seen in the 1.4% glycerol exchange, suggesting uncoupled water transport through water channels. Mass transfer area coefficients for urea, creatinine, and urate were similar for both solutions. Also, clearances of the macromolecules P2-microglobulin, albumin, IgG, and α2-macroglobulin were not different for the two osmotic agents. The median absorption was higher for glycerol, 71% compared to 49% for glucose ( p < 0.01), as could be expected from the lower molecular weight. The use of a 1.4% glycerol solution during a 4-hour dwell caused a small but significant median rise in plasma glycerol, from 0.22 mmol/L to 0.45 mmol/L ( p = 0.02). Dialysate cancer antigen 125 and lactate dehydrogenase (LDH) concentrations during the dwell were not different for both solutions. Conclusions These findings show that glycerol is an effective osmotic agent that can replace glucose in short dwells and show no acute mesothelial damage. The higher net ultrafiltration obtained with 1.4% glycerol can be explained by the higher initial net osmotic pressure gradient. This was seen especially in the first hour of the dwell. Thereafter, the osmotic gradient diminished as a result of absorption. The dip in dialysate-to-plasma ratio for sodium seen in the glycerol dwell can also be explained by this high initial osmotic pressure gradient, implying that the effect of glycerol as an osmotic agent is more dependent on intact water channels than is glucose.

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“…In particular, S values for glucose were negative and for urea and potassium greater than 1, independent of the applied glucose solution and the assumed value of peritoneal reabsorption, Q, ( Table 2). Recently it has been found that unphysical values of S appear to be specific for glucose-based peritoneal dialysis and are not observed for dialysis fluids with alternative osmotic agents, as amino acids or glycerol (8).…”

Section: Transport Parameters Versus Dialysis Fluid and Peritoneal Rementioning

confidence: 99%

Diffusive and Convective Solute Transport in Peritoneal Dialysis with Glucose as an Osmotic Agent

et al. 1995

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To investigate possible effects of glucose concentration, dwell time, and peritoneal reabsorption on the combined diffusive and convective peritoneal solute transport, dialysate to plasma concentration ratios (D/P) and solute clearances were evaluated for 6-h peritoneal dwell studies with 1.36, 2.27, and 3.86% glucose solutions. The diffusive mass transport coefficient, KBD, and sieving coefficient, S, were estimated using the Babb-Randerson-Farrell model of peritoneal transport. Dialysate volumes over time and peritoneal reabsorption rates, KE, were assessed using radiolabeled iodinated serum albumin (RISA). The transport parameters were estimated with and without peritoneal reabsorption of solutes taken into account. To test the stability of the transport parameters throughout a single peritoneal dwell, KBD and S values were estimated for the initial 3-120 min, the final 120-360 min, and the entire 3-360 min dwell period for dialysis with 3.86% glucose solution. The transport parameters did not differ between the three dialysis fluids although clearances of small solutes were higher with the 3.86% solution. Values of KBD, but not S, were dependent on the correction for peritoneal reabsorption of solutes. Computer simulations showed that S could be estimated even with the 1.36% glucose solution. A significant change of the transport parameters, with increased values of KBD during the initial period of the dwell, was found for urea, potassium, sodium, and total protein during dialysis with the 3.86% solution. S values for urea and potassium were close to 1 during the initial period whereas unphysical (higher than 1) S values were found for the whole dwell period. The transient increase of KBD during the initial part of the dwell may reflect changes in the peritoneal barrier possibly induced by fresh dialysis fluid. In conclusion, the transport parameters KBD and S are not influenced by the concentration of glucose in the dialysis fluid. Moreover, the estimation of KBD but not of S is dependent on the assumed rate of peritoneal reabsorption. Finally, the current results challenge the assumption that KBD and S are constant throughout a peritoneal dialysis exchange.

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Effect of Alternative Osmotic Agents on Peritoneal Transport

Cited by 30 publications

References 15 publications

Sieving Coefficients for Small Solutes during Experimental Peritoneal Dialysis in Rats

Sieving Coefficients for Small Solutes during Experimental Peritoneal Dialysis in Rats

Peritoneal Transport Characteristics with Glycerol-Based Dialysate in Peritoneal Dialysis

Diffusive and Convective Solute Transport in Peritoneal Dialysis with Glucose as an Osmotic Agent

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