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 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.

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 Customization of Peritoneal Dialysis in Cardiorenal Syndrome by Optimization of Sodium Extraction

2019 ◽  
Vol 9 (2) ◽  
pp. 117-124 ◽  
Author(s):  
Amir Kazory ◽  
Abhilash Koratala ◽  
Claudio Ronco
Keyword(s):  
Peritoneal Dialysis ◽  
Patient Population ◽  
Therapeutic Option ◽  
Free Water ◽  
Volume Overload ◽  
Cardiorenal Syndrome ◽  
Waste Products ◽  
Specific Patient ◽  
Fluid Removal ◽  
Sodium Removal

Background: Peritoneal dialysis (PD) has emerged as a mechanistically relevant therapeutic option for patients with heart failure (HF), volume overload, and varying degrees of renal dysfunction (i.e., chronic cardiorenal syndrome). Congestion has been identified as a potent ominous prognostic factor in this patient population, outperforming a number of established risk factors. As such, excess fluid removal is recognized as a relevant therapeutic target in this setting. Methods: Accumulating evidence points to the importance of sodium removal as part of any decongestive strategy because extraction of sodium-free water has little or no impact on the outcomes of these patients. Hence, optimization of sodium removal by PD should be the primary focus in the setting of HF and cardiorenal syndrome, especially if PD is started when the patient still has adequate residual renal function for clearance of waste products. Results: Herein, we provide an overview of approaches that can tailor PD treatment to the patients’ characteristics and clinical needs (e.g., choice of PD modality) to fully exploit its decongestive properties. Other methods that could prove helpful in the future will also be briefly discussed. Conclusion: While these strategies could help with efficient sodium extraction and volume optimization, future studies are needed to evaluate their impact on the outcomes of this specific patient population.

scholarly journals The cellular contribution to effluent potassium and its relation to free water transport during peritoneal dialysis

2007 ◽  
Vol 22 (12) ◽  
pp. 3593-3600 ◽  
Author(s):  
A. M. Coester ◽  
D. G. Struijk ◽  
W. Smit ◽  
D. R. de Waart ◽  
R. T. Krediet
Keyword(s):  
Peritoneal Dialysis ◽  
Water Transport ◽  
Free Water

scholarly journals Time Course of Peritoneal Function in Automated and Continuous Peritoneal Dialysis

2012 ◽  
Vol 32 (6) ◽  
pp. 605-611 ◽  
Author(s):  
Wieneke M. Michels ◽  
Marion Verduijn ◽  
Alena Parikova ◽  
Elisabeth W. Boeschoten ◽  
Dirk G. Struijk ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Repeated Measures ◽  
Time Course ◽  
Fluid Transport ◽  
Free Water ◽  
Transport Parameters ◽  
Lymphatic Absorption ◽  
Small Pore ◽  
Year 2000 ◽  
Over Time

♦ Background and ObjectivesIn automated peritoneal dialysis (APD), a patient's peritoneal membrane is more intensively exposed to fresh dialysate than it is in continuous ambulatory peritoneal dialysis (CAPD). Our aim was to study, in incident peritoneal dialysis (PD) patients, the influence of APD—compared with that of CAPD—on peritoneal transport over 4 years.♦ Design, Setting, Participants, and MeasurementsPatients were included if at least 2 annual standard permeability analyses (SPAs) performed with 3.86% glucose were available while the patient was using the same modality with which they had started PD (APD or CAPD). Patients were followed until their first modality switch. Differences in the pattern of SPA outcomes over time were tested using repeated-measures models adjusted for age, sex, comorbidity, primary kidney disease, and year of PD start.♦ ResultsThe 59 CAPD patients enrolled were older than the 47 APD patients enrolled (mean age: 58 ± 14 years vs 49 ± 14 years; p < 0.01), and they had started PD earlier (mean start year: 2000 vs 2002). Over time, no differences in solute ( p > 0.19) or fluid transport ( p > 0.13) were observed. Similarly, free water transport ( p = 0.43) and small-pore transport ( p = 0.31) were not different between the modalities. Over time, patients on APD showed a faster decline in effective lymphatic absorption rate (ELAR: p = 0.02) and in transcapillary ultrafiltration (TCUF: p = 0.07, adjusted p = 0.05). Further adjustment did not change the results.♦ ConclusionsCompared with patients starting on CAPD, those starting on APD experienced a faster decline in ELAR and TCUF. Other transport parameters were not different over time between the groups.

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.

Free Water Transport and its Association with Cardiovascular Status in Children on Peritoneal Dialysis

2019 ◽  
Vol 39 (4) ◽  
pp. 323-329
Author(s):  
Lilian Bolte ◽  
Maria Jose Ibacache ◽  
Iris Delgado ◽  
Francisco Cano
Keyword(s):  
Peritoneal Dialysis ◽  
Left Ventricular Hypertrophy ◽  
Water Transport ◽  
Ventricular Hypertrophy ◽  
Roc Analysis ◽  
Characteristic Curve ◽  
Negative Relationship ◽  
Free Water ◽  
Inverse Correlation ◽  
Left Ventricular

BackgroundVolume overload is one of the most important factors associated with left ventricular hypertrophy (LVH) and cardiovascular disease in chronic peritoneal dialysis (PD) patients. MiniPET is a reliable tool to evaluate free water transport (FWT). In a clinical setting, the significance of FWT has not been evaluated in terms of outcome in children on PD. The objective was to define a FWT value of clinical significance in children on PD, fixing its relationship to left ventricular mass index (LVMI) as a well-known outcome parameter.MethodsMiniPET was performed with 3.86% glucose, 1-h long, to measure FWT in PD patients > 6 years old. An echocardiogram (ECG) was performed within 2 months of the MiniPET. Left ventricular hypertrophy was defined as LVMI ≥ 38.6 g/height2.7(95th percentile). Receiver operating characteristic curve (ROC) analysis was used to determine the cut-off value of FWT searching the highest sensitivity and specificity to differentiate patients with normal/abnormal LVMI. A p < 0.05 was considered significant.ResultsForty-six studies were performed on 32 patients, 16 males; mean age 11.59 ± 3.07 years. Mean normalized FWT (nFWT) was 144.4 ± 84.8 mL/m2, corresponding to 46.7% of total ultrafiltration. Mean LVMI was 42 ± 11.3 g/m2.7with a negative correlation to nFWT ( p < 0.01). Eighteen out of 32 patients had LVH. The ROC analysis (nFWT vs LVMI) showed an area under the curve of 0.71 (95% confidence interval [CI], 0.53 – 0.89; p = 0.04), allowing a cut-off nFWT value of 110 mL/m2to be defined, dividing the population into 2 groups of patients according to the LVMI cut-off value of 38,6 g/m2.7.ConclusionsThe nFWT showed an inverse correlation to LVMI. A nFWT value < 110 mL/m2was significantly associated with LVH. The negative relationship observed between nFWT and LVMI, and the cut-off level for nFWT according to the 95th percentile of LVMI, suggest that the regular evaluation of nFWT could become a useful tool in assessing the capacity of PD treatment to keep patients’ volume status under control, avoiding cardiovascular impairment.

scholarly journals Measuring Peritoneal Absorption with the Prolonged Peritoneal Equilibration Test from 4 to 8 Hours Using Various Glucose Concentrations

2014 ◽  
Vol 34 (6) ◽  
pp. 605-611 ◽  
Author(s):  
Josep Teixidó–Planas ◽  
Maria Isabel Troya–Saborido ◽  
Guillermo Pedreira–Robles ◽  
Milagros Del-Rio–Lafuente ◽  
Ramon Romero–Gonzalez ◽  
...  
Keyword(s):  
Water Transport ◽  
Peritoneal Fluid ◽  
Glucose Solution ◽  
Free Water ◽  
Random Order ◽  
Practical Method ◽  
University Hospital ◽  
Transport Parameters ◽  
Peritoneal Equilibration Test ◽  
Small Pore

BackgroundPeritoneal fluid flows such as small-pore ultrafiltration and free water transport can now be calculated by means of the modified peritoneal equilibration test (PET). To calculate peritoneal fluid absorption, volume markers have been used, but that method is not easily applicable in clinical practice. Alternatively, absorption can be estimated using the personal dialysis capacity test. However, a method of measuring overall peritoneal absorption together with the PET is lacking. The aim of the present study was to assess whether overall peritoneal absorption was different when measured from the 4th to 8th hour in a prolonged PET using three different glucose solutions.MethodsThe study enrolled 32 stable peritoneal dialysis (PD) patients from a tertiary university hospital, who underwent three 8-hour prolonged PETs with 1.36%, 2.27%, and 3.86% glucose solution. The PETs were performed in random order over a period of less than 1 month. During the prolonged PET, the peritoneal volume was emptied and reinfused at 60 and 240 minutes and drained at 480 minutes. Peritoneal absorption was calculated as the volume difference between the 4th and the 8th hour.ResultsThe dialysate-to-plasma ratio (D/P) of urea, the D/P creatinine, and the mass transfer area coefficient (MTC) of creatinine at 240 minutes were not significantly different with the three glucose solutions. The end-to-initial (D/D0) glucose, MTC urea, and MTC glucose were significantly different. All water transport parameters were significantly different, except for the 4- to 8-hour absorption volumes and rates. The peritoneal absorption rates were, for 1.36% solution, 1.03 ± 0.58 mL/min [95% confidence interval (CI): 0.83 to 1.24 mL/min]; for 2.27% solution, 0.86 ± 0.71 mL/min (95% CI: 0.61 to 1.11 mL/min); and for 3.86% solution, 1.05 ± 0.78 mL/min (95% CI: 0.77 to 1.33 mL/min). Peritoneal absorption volumes and rates from the 4th to the 8th hour showed good correlations for the various solutions.ConclusionsUsing any glucose solution, the prolonged PET with voiding and reinfusion at the 4th hour could be a practical method for calculating overall peritoneal absorption from the 4th to the 8th hour in PD patients.

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