MO687FREE WATER TRANSPORT AND ABSOLUTE DIP OF DIALYSATE SODIUM CONCENTRATION: EARLY CLINICAL PARAMETERS FOR PERITONEAL FIBROSIS IN PD PATIENTS?

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Marisa Roldão ◽  
Rachele Escoli ◽  
Hernâni Gonçalves ◽  
Francisco Ferrer ◽  
Karina Lopes
Keyword(s):  
Peritoneal Dialysis ◽  
Water Transport ◽  
Pearson Correlation ◽  
Statistical Significance ◽  
Sodium Concentration ◽  
Ca 125 ◽  
Sodium Removal ◽  
Small Pore ◽  
Dialysate Sodium ◽  
Sodium Sieving

Abstract Background and Aims Reduction of peritoneal salt and water removal is an important cause of shortened patient and technique survival in peritoneal dialysis (PD). The aim of this study was to longitudinally analyze changes in fluid and solute transport parameters in PD patients during the first year of treatment, using peritoneal equilibration test (PET). Method Retrospective observational study of incident PD patients who underwent 4-hour 3.86% glucose PET with additional measurement of ultrafiltration at 1 hour, 1 month after PD initiation and 12 months later. Parameters of peritoneal transport such as dialysate-to-plasma ratio of creatinine (D/Pcreat), ultrafiltration at 1 and 4 hours, small-pore ultrafiltration (SPUF), free water transport (FWT), sodium removal and absolute dip of dialysate sodium concentration (ΔDNa) at 1 hour (as an expression of sodium sieving), were calculated. Serum cancer antigen 125 (CA-125) was also assessed. Clinical, analytical and demographic data were analyzed. Statistical analysis was performed using SPSS (Version 23 for Mac OSX). Results The average age of 16 incident PD patients was 58.69 ± 8.51 years, 10 (62.5%) were male and 5 (31.8%) were diabetic. Ten patients (62.5%) were on automated peritoneal dialysis (APD). One month after PD initiation, membrane characteristics were: D/P = 0.684 ± 0.589, total UF at 4h = 0.696 ± 0.283L, UF at 1h = 0.487 ± 0.162L, SPUF = 0.303 ± 0.359L, FWT = 0.207 ± 0.738L, %FWT = 51.855 ± 11.828%, sodium removal = 38.048 ± 16.087mmol/L and ΔDNa = 11.125 ± 3.34mmol/L. Average serum CA-125 was 51.206 ± 22.6U/mL. A paired sample t-test was performed to compare these parameters 1 and 12 months after PD initiation and revealed a statistically significant increase of 0.11± 0.196L (p=0.042) on SPUF and 18.607 ± 7.1mmol/L (p=0.019) on sodium removal. ΔDNa showed a decrease of 2.5 ± 0.743mmol/L (p=0.005) and % FWT of 11.782 ± 12.831% (p=0.002). FWT also showed a decrease of 0.168 ± 0.019L, total UF at 4h of 0.206 ± 0.142L and UF at 1h of 0.114 ± 0.243L, however did not reach statistical significance. D/Pcreat remained stable. CA-125 showed a mild decrease of 3.644 ± 22.364U/mL although not statistically significant. Pearson correlation revealed a positive correlation between the variation of total UF at 4h and the variation of FWT (r=0.553, p=0.026) and ΔDNa (r=0.503, p=0.047), but not with SPUF, sodium removal, D/Pcreat or CA-125, during the study follow-up period. Conclusion The reduction of FWT through aquaporins and, particularly, the reduction of ΔDNa as a sodium sieving measure, appear to be the first functional changes in peritoneal membrane, suggesting that fibrosis may begin soon after PD initiation. Our results indicate that FWT and ΔDNa can be used to access fibrotic peritoneal alterations earlier than other conventional parameters such as D/Pcreat.

Validation by Computer Simulation of Two Indirect Methods for Quantification of Free Water Transport in Peritoneal Dialysis

2005 ◽  
Vol 25 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Daniele Venturoli ◽  
Bengt Rippe
Keyword(s):  
Peritoneal Dialysis ◽  
Water Transport ◽  
Free Water ◽  
Hydraulic Permeability ◽  
Nephrol Dial Transplant ◽  
Peritoneal Equilibration Test ◽  
Simple Method ◽  
Sodium Removal ◽  
Relative Contribution ◽  
Small Pore

Background In peritoneal dialysis, approximately 40% of the total osmotic ultrafiltration (UF) induced by glucose can be predicted to be due to “free” water transport across aquaporin-1 (APQ-1). Theoretically, it would be possible to assess the fraction of free water transport in the early phase of a hypertonic dwell, when UF rate is high and the relative contribution of Na+ diffusion is low. La Milia et al. [La Milia V. et al. Fast-fast peritoneal equilibration test (FAST-FAST-PET): a simple method for peritoneal hydraulic permeability study [Abstract]. Nephrol Dial Transplant 2002; 17 (Suppl 1):17–18] suggested a technique to assess sodium-associated water transport based on sodium removal (Na+R) divided by the plasma Na+ concentration during a “fast-fast” (60 minute) peritoneal equilibration test (PET) for 3.86% glucose, yielding an estimate of the UF passing through the small pores (UFSP). Free water transport (UF through ultrasmall pores; UFUSP) was obtained by subtracting UFSP from total UF. Although peritoneal Na+ transport is almost totally convective, this technique will slightly overestimate small-pore UF due to the presence of some small-pore Na+ diffusion from the circulation during the dwell. A way of dealing with this problem was presented recently by Smit (Smit W. et al. Quantification of free water transport in peritoneal dialysis. Kidney Int 2004; 66:849–854). Methods In the present study we used the three-pore model of peritoneal transport to predict the degree of overestimation of UFSP for the technique presented by La Milia et al., and any potential deviations from theory for the technique presented by Smit et al. Simulations were performed under ordinary conditions and during simulated UF failure for 3.86% glucose. The fractional UF coefficient accounted for by APQ-1 was set at 2%. Results Estimating the UFSP from the sodium-associated water transport according to the method by La Milia et al. consistently overestimated UFSP and underestimated UFUSP. These errors were, however, minimal for dwells lasting between 30 and 80 minutes. The technique by Smit et al. to calculate aquaporin-mediated water flow (UFUSP), using an elaborate correction for Na+ diffusion from the circulation during the dwell, seemed accurate in most situations but, in general, tended to moderately overestimate UFUSP at early dwell times (<30 minutes) and underestimate UFUSP at long dwell times (4 hours). Conclusions The technique presented by La Milia et al. to calculate free water transport during a fast-fast PET was found to be surprisingly accurate, although the procedure would further improve by the introduction of a correction algorithm. The technique by Smit is even more accurate for dwells up to 4 hours’ duration. However, since the Smit technique is elaborate, it is less practical for routine determinations of aquaporin-mediated water transport in peritoneal dialysis.

scholarly journals Peritoneal Water Transport Characteristics of Diabetic Patients Undergoing Peritoneal Dialysis: A Longitudinal Study

2017 ◽  
Vol 46 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Ana Fernandes ◽  
Roi Ribera-Sanchez ◽  
Ana Rodríguez-Carmona ◽  
Antía López-Iglesias ◽  
Natacha Leite-Costa ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Water Transport ◽  
Free Water ◽  
Volume Overload ◽  
Diabetic Patients ◽  
Longitudinal Analyses ◽  
Cross Sectional ◽  
Sodium Removal ◽  
Essential Stability ◽  
Stability Of Water

Background: Volume overload is frequent in diabetics undergoing peritoneal dialysis (PD), and may play a significant role in the excess mortality observed in these patients. The characteristics of peritoneal water transport in this population have not been studied sufficiently. Method: Following a prospective, single-center design we made cross-sectional and longitudinal comparisons of peritoneal water transport in 2 relatively large samples of diabetic and nondiabetic PD patients. We used 3.86/4.25% glucose-based peritoneal equilibration tests (PET) with complete drainage at 60 min, for these purposes. Main Results: We scrutinized 59 diabetic and 120 nondiabetic PD patients. Both samples showed relatively similar characteristics, although diabetics were significantly more overhydrated than nondiabetics. The baseline PET disclosed lower ultrafiltration (mean 439 mL diabetics vs. 532 mL nondiabetics, p = 0.033) and sodium removal (41 vs. 53 mM, p = 0.014) rates in diabetics. One hundred and nine patients (36 diabetics) underwent a second PET after 12 months, and 45 (14 diabetics) underwent a third one after 24 months. Longitudinal analyses disclosed an essential stability of water transport in both groups, although nondiabetic patients showed a trend where an increase in free water transport (p = 0.033) was observed, which was not the case in diabetics. Conclusions: Diabetic patients undergoing PD present lower capacities of ultrafiltration and sodium removal than their nondiabetic counterparts. Longitudinal analyses disclose an essential stability of water transport capacities, both in diabetics and nondiabetics. The clinical significance of these differences deserves further analysis.

Fluid and Solute Transport using Different Sodium Concentrations in Peritoneal Dialysis Solutions

2001 ◽  
Vol 21 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Hui-Hong Cheng ◽  
Tao Wang ◽  
Olof Heimbürger ◽  
Jonas Bergström ◽  
Bengt Lindholm
Keyword(s):  
Peritoneal Dialysis ◽  
Sodium Transport ◽  
Concentration Gradient ◽  
Peritoneal Fluid ◽  
Glucose Solution ◽  
Sodium Concentration ◽  
Transport Rate ◽  
Diffusive Transport ◽  
Sodium Removal ◽  
Dialysis Solutions

Background Fluid and sodium balance is important for the success of long-term peritoneal dialysis. Convective transport is the major determinant for sodium removal during peritoneal dialysis using conventional dialysis solutions. However, recent studies showed that lower sodium concentration in dialysate could significantly increase sodium removal by increasing the diffusion gradient, thereby increasing diffusive transport. In the present study, we investigated the influence of the sodium concentration gradient on the diffusive transport coefficient, KBD for sodium. Methods A 4-hour dwell study was done in Sprague–Dawley rats using 25 mL 5% glucose (NS), 5% glucose + 0.3% NaCl (LS), 5% glucose + 0.6% NaCl (MS), or 5% glucose + 0.9% NaCl (HS), with frequent dialysate and blood sampling. Radiolabeled human albumin (RISA) was added to the solution as an intraperitoneal volume marker. The peritoneal fluid and sodium transport characteristics were evaluated. Results Significant ultrafiltration (both net ultrafiltration and transcapillary ultrafiltration) was observed in each group despite the osmolality of the 5% glucose solution being slightly lower than the plasma osmolality. There was no difference in peritoneal fluid absorption rate and direct lymphatic absorption among the four groups. With the sieving coefficient for sodium set to 0.55, a significantly higher KBD for sodium was found in the NS compared to the HS group. The KBD for sodium was 0.21 ± 0.01, 0.20 ± 0.01, 0.17 ± 0.01, and 0.09 ± 0.01 mL/min for the NS, LS, MS, and HS groups, respectively. The KBD values for glucose were significantly lower in the NS and LS groups compared to the MS and HS groups. Conclusions Our results suggest that ( 1 ) sodium concentration may affect peritoneal sodium KBD — as the sodium concentration gradient increased, the KBD decreased; ( 2 ) 5% glucose solution could induce significant peritoneal ultrafiltration in normal rats despite its initial hypo-osmotic nature, this was due to the significantly lower glucose transport rate than sodium transport rate; and ( 3 ) a lower dialysate sodium concentration may decrease peritoneal glucose absorption.

scholarly journals The contribution of free water transport and small pore transport to the total fluid removal in peritoneal dialysis

2005 ◽  
Vol 68 (4) ◽  
pp. 1849-1856 ◽  
Author(s):  
Alena Parikova ◽  
Watske Smit ◽  
Dirk G. Struijk ◽  
Machteld M. Zweers ◽  
Raymond T. Krediet
Keyword(s):  
Peritoneal Dialysis ◽  
Water Transport ◽  
Free Water ◽  
Fluid Removal ◽  
Small Pore ◽  
Total Fluid

scholarly journals How Would You Prescribe the Dialysate Sodium Concentration for Your Patients?

2021 ◽  
Vol 2 (1) ◽  
pp. 1-3
Author(s):  
Friedrich K. Port
Keyword(s):  
Blood Pressure ◽  
Recent Trend ◽  
Sodium Concentration ◽  
Intradialytic Hypotension ◽  
Sodium Removal ◽  
Low Sodium ◽  
Interdialytic Weight Gain ◽  
Increased Risk ◽  
Dialysate Sodium ◽  
Intradialytic Symptoms

Low sodium dialysate was commonly used in the early year of hemodialysis to enhance diffusive sodium removal beyond its convective removal by ultrafiltration. However, disequilibrium syndrome was common, particularly when dialysis sessions were reduced to 4 h. The recent trend of lowering the DNa from the most common level of 140 mEq/L has been associated with intradialytic hypotension and increased risk of hospitalization and mortality. Higher DNa also has disadvantages, such as higher blood pressure and greater interdialytic weight gain, likely due to increased thirst. My assessment of the evidence leads me to choose DNa at the 140 level for most patients and to avoid DNa below 138. Patients with intradialytic symptoms may benefit from DNa 142 mEq/L, if they can avoid excessive fluid weight gains.

scholarly journals Analysis of Ultrafiltration Failure Diagnosed at the Initiation of Peritoneal Dialysis with the Help of Peritoneal Equilibration Tests with Complete Drainage at Sixty Minutes. A Longitudinal Study

2016 ◽  
Vol 36 (4) ◽  
pp. 442-447 ◽  
Author(s):  
Daniela Machado Lopes ◽  
Ana Rodríguez-Carmona ◽  
Teresa García Falcón ◽  
Andrés López Muñiz ◽  
Tamara Ferreiro Hermida ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Water Transport ◽  
Time Course ◽  
Free Water ◽  
Control Group ◽  
First Year ◽  
Study Group ◽  
Ultrafiltration Failure ◽  
Small Pore

BackgroundUltrafiltration failure (UFF) diagnosed at the initiation of peritoneal dialysis (PD) has been insufficiently characterized. In particular, few longitudinal studies have analyzed the time course of water transport in patients with this complication.ObjectiveTo investigate the time course of peritoneal water transport during the first year on PD in patients presenting UFF since the initiation of this therapy (study group).MethodProspective, observational, single-center design. We analyzed, at baseline and after 1 year of follow-up, peritoneal water transport in 19 patients incident on PD with UFF. We used incident patients without UFF as a control group. Water transport was characterized with the help of 3.86/4.25% dextrose-based peritoneal equilibration tests (PETs) with complete drainage at 60 minutes.ResultsThe study group revealed a disorder of water transport affecting both small-pore ultrafiltration (SPUF) ( p = 0.054 vs incident without UFF) and free water transport (FW T) ( p = 0.001). After 1 year of follow-up, FWT displayed a general increasing trend in the study group (mean variation 48.9 mL, 95% confidence interval [CI] 15.5, 82.2, p = 0.012), while the behavior of SPUF was less predictable (-4.8 mL, 95% CI -61.4, 71.1, p = 0.85). These changes were not observed in incident patients without UFF. Neither initial clinical characteristics, baseline PET-derived parameters, or suffering peritoneal infections during the first year predicted the time course of the capacity of UF in the study group. Recovery from incident UFF was apparently linked to improvement of SPUF.ConclusionsPatients with UFF at the start of PD suffer a disorder of peritoneal water transport affecting both FWT and SPUF. Free water transport increases systematically in these patients after 1 year of follow-up. The evolution of SPUF is less predictable, and improvement of this parameter marks reversibility of this complication.

Sodium removal and sodium concentration during peritoneal dialysis: effects of three methods of sodium measurement

2004 ◽  
Vol 19 (7) ◽  
pp. 1849-1855 ◽  
Author(s):  
V. La Milia ◽  
S. Di Filippo ◽  
M. Crepaldi ◽  
S. Andrulli ◽  
L. Del Vecchio ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Sodium Concentration ◽  
Sodium Removal

scholarly journals Ultrafiltration Failure and Impaired Sodium Sieving during Long-Term Peritoneal Dialysis: More than Aquaporin Dysfunction?

2016 ◽  
Vol 36 (2) ◽  
pp. 227-231 ◽  
Author(s):  
Johann Morelle ◽  
Amadou Sow ◽  
Nicolas Hautem ◽  
Olivier Devuyst ◽  
Eric Goffin
Keyword(s):  
Peritoneal Dialysis ◽  
Water Transport ◽  
Free Water ◽  
Peritoneal Fibrosis ◽  
Osmotic Water ◽  
Ultrafiltration Failure ◽  
Normal Expression ◽  
Initial Hypothesis ◽  
Sodium Sieving

Fifteen years ago, our group reported the case of a 67-year-old man on peritoneal dialysis for 11 years, in whom ultrafiltration failure and impaired sodium sieving were associated with an apparently normal expression of aquaporin-1 (AQP1) water channels in peritoneal capillaries. At that time, AQP1 dysfunction was suggested as the cause of impaired free-water transport. However, recent data from computer simulations, and structural and functional analysis of the peritoneal membrane of patients with encapsulating peritoneal sclerosis, demonstrated that changes in the peritoneal interstitium directly alter osmotic water transport. In light of these insights, we challenge the initial hypothesis and provide several lines of evidence supporting the diagnosis of encapsulating peritoneal sclerosis in this patient and suggesting that severe peritoneal fibrosis accounted for the loss of osmotic conductance developed during the course of peritoneal dialysis.

scholarly journals What Is the Optimal Dialysate Sodium Concentration?

2021 ◽  
Vol 1 (2) ◽  
pp. 157-160
Author(s):  
Elizabeth Lindley ◽  
James Tattersall
Keyword(s):  
Fluid Balance ◽  
Serum Sodium ◽  
Sodium Intake ◽  
Sodium Concentration ◽  
Sodium Removal ◽  
Lower Fluid ◽  
Dialysate Sodium

In haemodialysis, sodium and fluid balance (where intake matches loss) is achieved by ultrafiltration and by diffusion between the plasma water and dialysate. If a patient’s sodium intake does not change, any reduction in fluid gain obtained by lowering dialysate sodium concentration will result in less sodium removal by ultrafiltration. The corresponding change in diffusion to achieve balance may mean the benefit of lower fluid gain is offset by morbidity caused by a fall in serum sodium during dialysis. The standard dialysate sodium should minimise harm caused by both high ultrafiltration rates and osmotic disequilibrium. For most units, this is likely to be 138 to 140 mmol/L.

Sodium Sieving in Children

2005 ◽  
Vol 25 (3_suppl) ◽  
pp. 141-142 ◽  
Author(s):  
Esther Rusthoven ◽  
Raymond T. Krediet ◽  
Hans L. Willems ◽  
Leo A. Monnens ◽  
Cornelis H. Schröder
Keyword(s):  
Peritoneal Dialysis ◽  
Water Transport ◽  
Minor Role ◽  
Peritoneal Membrane ◽  
A Minor ◽  
Sodium Sieving

Sodium sieving is a consequence of dissociation between the amount of water and sodium transported over the peritoneal membrane. This dissociation occurs in the presence of aquaporin-mediated water transport. Sieving of sodium can be used as a rough measure for aquaporin-mediated water transport. Icodextrin contains glucose polymers, inducing ultrafiltration by colloid osmosis. Therefore, aquaporins play a minor role in ultrafiltration, which is confirmed by the absence of sodium sieving. Icodextrin is very suitable for the daytime dwell in children on a nightly intermittent peritoneal dialysis regimen. Ultrafiltration obtained with icodextrin is similar to ultrafiltration obtained with 3.86% glucose after a 12-hour dwell. When using icodextrin in children, it is also confirmed by the absence of sodium sieving that the aquaporins play a minor role in ultrafiltration.

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