Urea Peritoneal Transfer Evaluated Using Plasma Water Urea Concentrations

1994 ◽  
Vol 14 (3) ◽  
pp. 243-247 ◽  
Author(s):  
Alicja E. Grzegorzewska
Keyword(s):  
Peritoneal Dialysis ◽  
Dwell Time ◽  
Transport Coefficients ◽  
Urea Concentration ◽  
Transport Parameters ◽  
Dialysis Unit ◽  
Blood Samples ◽  
Peritoneal Transport ◽  
Transfer Parameters ◽  
Water Values

Objective To quantify differences in evaluation of urea peritoneal transport parameters according to the expression of urea concentration in whole plasma and plasma water. Design Prospective study in which the dialysate samples for urea determinations were taken at short dwell times (2.5 45 minutes) during three consecutive exchanges of intermittent peritoneal dialysis (IPD). Blood samples were drawn at the beginning and at the end of the study period. Urea peritoneal transport parameters were calculated using urea concentration in whole plasma and plasma water. The results were then compared. Setting Peritoneal dialysis unit of a nephrology de partment. Patients Ten stable patients on IPD. Interventions Dialysateand blood sample collections.. Main Outcome Measures: Dialysate-to-plasma ratios (DIP), peritoneal clearances (Cp)’ and diffusive mass transport coefficients (KBD) of urea. Results At short dwell times, uncorrected (whole plasma) DIP and Cp of urea values were higher than the corrected (plasma water) values by 5.7% -5.9%. Uncorrected urea KBD’ calculated using the simplified two sample model of Garred et al., yielded an overestimation that significantly increased with prolongation of dwell (8.5±0.5% at 2.5 minutes vs 13.0±0.8% at 45 minutes). Urea KBD’ assessed by the linear regression model of Garred and Spencer, was 9.4±0.3% higher for uncorrected values. Conclusions The expression of urea concentration in whole plasma instead of plasma water overestimates urea peritoneal transfer parameters. The percent overestimation (y) of urea KBD’ calculated using the simplified model of Garred et al., can be predicted with the equation y = 0.131x+ 7.563, wherex is the dwell time (in minutes).

On the change of transport parameters with dwell time during peritoneal dialysis

2020 ◽  
pp. 089686082097151
Author(s):  
Jacek Waniewski ◽  
Joanna Stachowska-Pietka ◽  
Bengt Lindholm
Keyword(s):  
Peritoneal Dialysis ◽  
Clinical Data ◽  
Dwell Time ◽  
Dialysis Fluid ◽  
Transport Parameters ◽  
Satisfactory Description ◽  
Pore Model ◽  
Vasodilatory Effect ◽  
Peritoneal Transport ◽  
Molecular Radius

The transitory change of fluid and solute transport parameters occurring during the initial phase of a peritoneal dialysis dwell is a well-documented phenomenon; however, its physiological interpretation is rather hypothetical and has been disputed. Two different explanations were proposed: (1) the prevailing view—supported by several experimental and clinical studies—is that a vasodilatory effect of dialysis fluid affects the capillary surface area available for dialysis, and (2) a recently presented alternative explanation is that the molecular radius of glucose increases due to the high glucose concentration in fresh dialysis fluid and that this change affects peritoneal transport parameters. The experimental bases for both phenomena are discussed as well as the problem of the accuracy necessary for a satisfactory description of clinical data when the three-pore model of peritoneal transport is applied. We show that the correction for the change of transport parameters with dwell time provides a better fit with clinical data when applying the three-pore model. Our conclusion is in favor of the traditional interpretation namely that the transitory change of transport parameters with dwell time during peritoneal dialysis is primarily due to the vasodilatory effect of dialysis fluids.

How Accurate is the Description of Transport Kinetics in Peritoneal Dialysis According to Different Versions of the Three-Pore Model?

2008 ◽  
Vol 28 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Jacek Waniewski ◽  
Malgorzata Debowska ◽  
Bengt Lindholm
Keyword(s):  
Peritoneal Dialysis ◽  
Solute Transport ◽  
Peritoneal Fluid ◽  
Dwell Time ◽  
Transport Kinetics ◽  
Transport Parameters ◽  
Pore Model ◽  
Peritoneal Transport ◽  
Endogenous Protein ◽  
Dialysate Volume

Objective The three-pore model of peritoneal transport is used extensively for modeling peritoneal fluid and solute transport, but the currently used versions include certain modifications of the transport parameters that have not been validated quantitatively versus detailed data on fluid and solute kinetics. The aim of this study was to evaluate different versions of the three-pore model. Method Detailed clinical peritoneal fluid and solute transport data were obtained from 40 peritoneal dwell studies in clinically stable continuous ambulatory peritoneal dialysis patients in whom the dialysate volume was measured using a macromolecular volume marker (RISA). Results Using a new version of the three-pore model with several adjusted transport parameters, good agreement between the measured and the simulated values of dialysate volume and concentrations of small solutes and RISA (but not of endogenous protein) versus dwell time was obtained; however, the predicted peritoneal absorption for longer than the investigated dwell time would be too high. Conclusion The three-pore model, with some adjustments proposed in this study, may be used for detailed description of peritoneal transport kinetics, but it should be pointed out that, even after these adjustments, it still does not provide the correct description of peritoneal fluid absorption and transport of macromolecules.

Results of Peritoneal Equilibration Test during Treatment with Polyglucose Dialysis Solution

2002 ◽  
Vol 22 (3) ◽  
pp. 357-364 ◽  
Author(s):  
Alicja E. Grzegorzewska ◽  
Danuta Antczak-Jȩdrzejczak ◽  
Magdalena Leander
Keyword(s):  
Peritoneal Dialysis ◽  
Dwell Time ◽  
Control Period ◽  
University Hospital ◽  
Control Group ◽  
Peritoneal Equilibration Test ◽  
Dialysis Unit ◽  
Dialysis Solution ◽  
Glucose Ratio ◽  
Peritoneal Permeability

Background Results of peritoneal equilibration test (PET) suggest prolonged effect of polyglucose dialysis solution (PG-DS) on peritoneal permeability. Objectives An evaluation of dialysate-to-plasma ratio (D/P) of urea, D/P creatinine, and D/D0 glucose (ratio of dialysate glucose at designated dwell time to dialysate glucose at 0 dwell time), and mass transfer area coefficients (KBD) of these solutes in PET before introduction, during administration, and after discontinuation of PG-DS in patients treated with continuous ambulatory peritoneal dialysis (CAPD). Design Single-center prospective study with PG-DS; retrospective selection of the control group. Setting Peritoneal dialysis unit in a university hospital. Patients Fourteen patients (11 males; age 45.1 ± 8.5 years) treated with CAPD for 17.5 ± 9.9 months. 7.5% PG-DS was used for the overnight exchange. After discontinuation of the PG-DS, standard dialysis solutions, as previously used, were reintroduced. The control group was selected to match both CAPD duration and peritoneal permeability of the patients in the PG-DS group at the start of the study. Methods Standard PET was carried out at 1.6 ± 0.8 months before the introduction of PG-DS (study period I, n = 14), after 1.2 ± 0.6 months’ use of PG-DS (study period II, n = 14), after 4.4 ± 0.8 months’ use of PG-DS (study period III, n = 11), after 8.8 ± 2.2 months’ use of PG-DS (study period IV, n = 9), and at 2.0 ± 0.6 months after PG-DS discontinuation (study period V, n = 11). Patients in the control group underwent PET at similar time intervals (control periods I – V). Results In the PG-DS group, a tendency toward increased peritoneal permeability for urea and creatinine was shown during the consecutive study periods. D/D0 glucose was significantly higher only in the PET performed during use of PG-DS (periods II – IV) compared to results obtained in period I. In the control group, both D/P and KBD of both urea and creatinine remained unchanged, but KBD glucose was higher in the first 2 hours of the PET in control period V compared to respective values in control period III. Conclusion Changes in peritoneal permeability are observed in CAPD patients treated with PG-DS. These changes may be at least partially related to the administration of polyglucose.

Evaluation of the Peritoneal Equilibration Test in Children on Chronic Peritoneal Dialysis

1993 ◽  
Vol 13 (2_suppl) ◽  
pp. 260-262 ◽  
Author(s):  
Alberto Edefonti ◽  
Marina Picca ◽  
Raffaele Galato ◽  
Sophie Guez ◽  
Marisa Giani ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Dwell Time ◽  
Glucose Solution ◽  
Transport Rate ◽  
Chronic Peritoneal Dialysis ◽  
Automated Peritoneal Dialysis ◽  
Peritoneal Equilibration Test ◽  
Blood Samples ◽  
Mean Values ◽  
Significant Difference

The peritoneal equilibration test (PET) is routinely performed in adults treated with chronic peritoneal dialysis to assess the peritoneal transport rate and to optimize treatment prescription. Only a few and not well-standardized studies on the PET have been reported in children. Twenty-six PETs were performed In 16 children, mean age 10.9±4.9 years, mean body weight (BW) 26.8±11.9 kg, treated with nightly intermittent peritoneal dialysis (NIPD). The PET was performed according to Twardowski. Forty mL/kg BW of 2.27% glucose solution were Infused at a rate of 10 mL/kg BW every 2 minutes. In the simplified test, dialysate samples were taken at dwell times 0, 2 and 4 hours for glucose and creatinine. A blood sample was taken after a 2-hour dwell time for the same parameters. The standard PET (8 patients) consisted of dialysate samples at 0, 15, 30, 60, 120, and 240 minutes and blood samples at 0 and 240 minutes. Mean DIP ratio for corrected creatinine and DIDo ratio for glucose at 2 hours were 51.6±11.6 and 50.4±9, respectively; at 4 hours 69.6± 12 and 34.4±9.8, respectively. There was good correlation between DIP creatinine and DIDo glucose at 4 hours (p<0.0001). Patients were classified as high (3 cases), high-average (5), low-average (6), and low (2) transporters. A statistically significant difference was found between the curves obtained by the simplified PET and those of the standard PET In the first hour (r=0.66; p<0.05). In conclusion, the PET, modified for use in children, gave reliable and reproducible results. Mean values of DIP creatinine for children were higher and DIDo glucose lower than those of adults as reported by Twardowskl. A consistent percentage of children had, nevertheless, a low-average or low transport rate. Standard PET is required in case of automated peritoneal dialysis prescription.

Efficacy of Peritoneal Dialysis during Infusion and Drainage Procedures

2010 ◽  
Vol 30 (6) ◽  
pp. 633-637 ◽  
Author(s):  
Daniel Baczyński ◽  
Stefan Antosiewicz ◽  
Jacek Waniewski ◽  
Zbigniew Nowak ◽  
Zofia Wańkowicz
Keyword(s):  
Peritoneal Dialysis ◽  
Kinetic Modeling ◽  
Dwell Time ◽  
Uremic Toxin ◽  
Dialysis Fluid ◽  
Fluid Exchange ◽  
Peritoneal Transport ◽  
Toxin Removal ◽  
Technique Failure ◽  
Precise Assessment

BackgroundInadequate dialysis is still a major cause of technique failure in peritoneal dialysis (PD). Mathematical models provide the possibility of direct and precise assessment of peritoneal transport of urea and creatinine throughout the dwell and allow calculation of optimal schedules, dwell times, and predicted adequacy of a prescribed regimen. Kinetic modeling is particularly important for automated PD. If the effectiveness of uremic toxin removal that takes place during infusion and drainage of dialysis fluid is not taken into account, the predicted adequacy of the whole PD session may be underestimated.AimsTo estimate the efficacy of urea and creatinine removal during the dialysis fluid exchange procedure.Material and Methods17 patients treated with PD were included in the study. PD effectiveness during dialysate exchange was defined as the quotient k of removed amount of creatinine/BUN during the infusion and drainage of dialysate and during a dwell of the same duration as the dialysate exchange.ResultsThe effectiveness of creatinine and urea removal was reduced during the exchange procedure ( kcreat= 0.68 ± 0.43 and kBUN= 0.87 ± 0.44) and differed between these 2 solutes ( p = 0.0009). The k coefficients for urea and creatinine were well correlated ( R2= 0.83).ConclusionsThe effectiveness of peritoneal transport of creatinine and BUN during the inflow/outflow phase was relatively high compared to that during the same dwell time (68% and 87% respectively). This real effectiveness of the dialysate exchange procedure should be taken into account in the process of planning automated PD sessions, otherwise the predicted overall efficacy of creatinine and urea removal throughout the session may be underestimated. This underestimation is proportional to the number of dwells per day.

Peritoneal Fluid Transport in CAPD Patients with Different Transport Rates of Small Solutes

2004 ◽  
Vol 24 (3) ◽  
pp. 240-251 ◽  
Author(s):  
Danuta Sobiecka ◽  
Jacek Waniewski ◽  
Andrzej Weryński ◽  
Bengt Lindholm
Keyword(s):  
Peritoneal Dialysis ◽  
Solute Transport ◽  
Osmotic Pressure ◽  
Absorption Rate ◽  
Fluid Transport ◽  
Transport Coefficients ◽  
Dialysis Fluid ◽  
Transport Parameters ◽  
Ultrafiltration Rate ◽  
Small Solute

Background Continuous ambulatory peritoneal dialysis (CAPD) patients with high peritoneal solute transport rate often have inadequate peritoneal fluid transport. It is not known whether this inadequate fluid transport is due solely to a too rapid fall of osmotic pressure, or if the decreased effectiveness of fluid transport is also a contributing factor. Objective To analyze fluid transport parameters and the effectiveness of dialysis fluid osmotic pressure in the induction of fluid flow in CAPD patients with different small solute transport rates. Patients 44 CAPD patients were placed in low ( n = 6), low-average ( n = 13), high-average ( n = 19), and high ( n = 6) transport groups according to a modified peritoneal equilibration test (PET). Methods The study involved a 6-hour peritoneal dialysis dwell with 2 L 3.86% glucose dialysis fluid for each patient. Radioisotopically labeled serum albumin was added as a volume marker. The fluid transport parameters (osmotic conductance and fluid absorption rate) were estimated using three mathematical models of fluid transport: ( 1 ) Pyle model (model P), which describes ultrafiltration rate as an exponential function of time; ( 2 ) model OS, which is based on the linear relationship of ultrafiltration rate and overall osmolality gradient between dialysis fluid and blood; and ( 3 ) model G, which is based on the linear relationship between ultrafiltration rate and glucose concentration gradient between dialysis fluid and blood. Diffusive mass transport coefficients (KBD) for glucose, urea, creatinine, potassium, and sodium were estimated using the modified Babb–Randerson–Farrell model. Results The high transport group had significantly lower dialysate volume and glucose and osmolality gradients between dialysate and blood, but significantly higher KBD for small solutes compared with the other transport groups. Osmotic conductance, fluid absorption rate, and initial ultrafiltration rate did not differ among the transport groups for model OS and model P. Model G yielded unrealistic values of fluid transport parameters that differed from those estimated by models OS and P. The KBD values for small solutes were significantly different among the groups, and did not correlate with fluid transport parameters for model OS. Conclusion The difference in fluid transport between the different transport groups was due only to the differences in the rate of disappearance of the overall osmotic pressure of the dialysate, which was a combined result of the transport rate of glucose and other small solutes. Although the glucose gradient is the major factor influencing ultrafiltration rate, other solutes, such as urea, are also of importance. The counteractive effect of plasma small solutes on transcapillary ultrafiltration was found to be especially notable in low transport patients. Thus, glucose gradient alone should not be considered the only force that shapes the ultrafiltration profile during peritoneal dialysis. We did not find any correlations between diffusive mass transport coefficients for small solutes and fluid transport parameters such as osmotic conductance or fluid and volume marker absorption. We may thus conclude that the pathway(s) for fluid transport appears to be partly independent from the pathway(s) for small solute transport, which supports the hypothesis of different pore types for fluid and solute transport.

Changes in Peritoneal Transport during the First Month of Peritoneal Dialysis

1995 ◽  
Vol 15 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Michael V. Rocco ◽  
Jean R. Jordan ◽  
John M. Burkart
Keyword(s):  
Peritoneal Dialysis ◽  
Medical Center ◽  
Group Versus ◽  
Dialysis Patients ◽  
Dialysis Unit ◽  
Peritoneal Transport ◽  
Time Period ◽  
Initiation Of Dialysis ◽  
Calculated Mass

Objective To determine if peritoneal transport characteristics change during the initial month of peritoneal dialysis. Design Retrospective review of peritoneal equilibration test (PET) results in patients who received their first PET during the first two weeks of peritoneal dialysis (early PET group) versus patients who received their first PET between four and 28 weeks after the initiation of dialysis (late PET group). The initial PET values were compared to subsequent PET results obtained approximately seven months after the initial PET. Setting Peritoneal dialysis unit of a tertiary medical center. Outcome Measures PET results and calculated mass transfer area coefficient (MT AC) values. Patients Thirty-four peritoneal dialysis patients in the early PET group and 17 peritoneal dialysis patients in the late PET group. Results In the early PET group, there was a statistically significant increase from the initial to follow-up values for both dialysate-to-plasma (DIP) creatinine and MTAC creatinine (p < 0.01) as well as a significant decrease for four-hour dialysate to initial dialysate ratios (DID) glucose (p = 0.08) and MTAC glucose (p < 0.05). In the late PET group, there was no significant change in any of these parameters with time. However, in the late PET group, there was a significant decrease in DIP urea values with time (p < 0.01), but not with MTAC urea. In addition, there were no differences over time in either group for serum albumin or hematocrit values. Conclusion During the first two weeks of peritoneal dialysis, there tends to be a change in peritoneal transport characteristics in some patients. PET data obtained during this time period should be interpreted as preliminary.

Peritoneal Sclerosis in Chronic Peritoneal Dialysis Patients: Analysis of Clinical Presentation, Risk Factors, and Peritoneal Transport Kinetics

1997 ◽  
Vol 17 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Pascale M.E.M. Hendriks ◽  
Marja M. Ho-Dac Pannekeet ◽  
Thomas M. Van Gulik ◽  
Dirk G. Struijk ◽  
Saphire S.K.S. Phoa ◽  
...  
Keyword(s):  
Risk Factors ◽  
Peritoneal Dialysis ◽  
Bowel Obstruction ◽  
Control Group ◽  
Academic Medical Centre ◽  
Dialysis Unit ◽  
Presenting Symptoms ◽  
Peritoneal Transport ◽  
Number Of Patients ◽  
Glucose Exposure

Objective To analyze clinical features of peritoneal sclerosis (PS) in a group of peritoneal dialysis (PD) patients, and to compare potential risk factors and peritoneal transport characteristics with a control group matched for duration of PD. Design Study 1: Retrospective study of 16 PD patients with PS. Study 2: Case-control study comparing 10 patients with evident PS to 30 control patients who were matched for duration of PD. Setting Continuous Ambulatory Peritoneal Dialysis unit in the Academic Medical Centre in Amsterdam. Results The incidence of PS was 3.5 per 1000 patient years. PS was diagnosed either during PD (n = 10), in patients on hemodialysis (n = 2), or after successful transplantation (n = 4). Presenting symptoms were bowel obstruction, ascites, blood-stained effluent, and impaired net ultrafiltration. Macroscopic confirmation of the diagnosis was possible in 13 patients. Sclerotic encapsulation was present in 8 of them. Patients with PS were divided into three groups based on clinical symptoms and typical macroscopical findings. In category I the diagnosis PS was obvious (10 patients), in category II the diagnosis was highly suggestive (3 patients), and in category III it was doubtful (3 patients). Treatment was conservative in most patients. Surgical treatment was only possible in four and immunosuppressive therapy was given in 5 patients. Peritoneal sclerosis was the direct cause of death in 1 patient. Five patients died during follow-up due to other causes. At present, 7 patients are well and 3 patients (all from category I) still have recurrent bowel obstruction. Compared to matched controls, no difference existed in peritonitis incidence, or in the percentage of patients with former renal transplantations. The number of patients treated with β-blocking agents and the number of previous abdominal surgeries were not different. The number of catheter-related surgical procedures was higher in the PS patients than in the control group. The mass transfer area coefficient (MTAC) of creatinine was higher in PS patients and net ultrafiltration with 1.36% glucose was lower. The estimated cumulative glucose exposure until the diagnosis of PS was made was larger in PS patients than in their controls. This difference was already present in the first year of PD treatment in 8 of 10 patients. The initial values for the MTAC creatinine were similar in both groups. Conclusions The presenting symptoms of PS were bowel obstruction, ascites, and blood-stained effluent, often in combination with loss of net ultrafiltration. Peritoneal sclerosis is a complication of long-duration PD and could also become manifest after a successful renal transplant. Treatment should be conservative unless complications require surgical intervention. Patients with PS had lower net ultrafiltration and higher transport rates compared to controls who were matched for duration of PD. Although peritonitis incidence was similar, a relation of PS with severe peritonitis may be present in some patients. Glucose exposure is likely to be an important risk factor for PS.

Effects of Oral Paricalcitol and Calcitriol Treatment on Peritoneal Membrane Characteristics of Peritoneal Dialysis Patients — A Pilot Study

2018 ◽  
Vol 38 (3) ◽  
pp. 220-228 ◽  
Author(s):  
Karima Farhat ◽  
Andrea W.D. Stavenuiter ◽  
Marc G. Vervloet ◽  
Pieter M. ter Wee ◽  
Robert H.J. Beelen ◽  
...  
Keyword(s):  
Vitamin D ◽  
Peritoneal Dialysis ◽  
Parathyroid Hormone ◽  
Pilot Study ◽  
Peritoneal Membrane ◽  
Transport Parameters ◽  
Active Vitamin ◽  
Active Vitamin D ◽  
Markers Of Inflammation ◽  
Peritoneal Transport

BackgroundLong-term peritoneal dialysis (PD) is frequently complicated by technique failure preceded by peritoneal remodeling. Vitamin D has potent immunomodulatory characteristics: anti-inflammatory, anti-angiogenic, anti-fibrotic properties, and influences on the macrophage phenotype. Little is known about the relation between pleiotropic effects attributed to vitamin D3and the peritoneal membrane and what is the most appropriate vitamin D sterol in prevention of peritoneal remodeling in PD patients. Animal studies have suggested that paricalcitol has advantageous effects: decrease in plasma markers of inflammation, less peritoneal fibrosis, less pronounced PD-induced omental angiogenesis, and prevention of loss of ultrafiltration. We investigated whether paricalcitol is advantageous over calcitriol in PD patients.MethodA multicenter open-label 1:1 randomized non-blinded clinical pilot study enrolled prevalent continous ambulatory PD (CAPD) patients for a period of 6 months comparing paricalcitol with calcitriol. All patients were treated with biocompatible PD fluids. The primary endpoint was peritoneal transport parameters, exploratory endpoints were biomarkers of peritoneal damage and cell analysis (including M1/M2 macrophages), and safety endpoints were metabolic parameters.ResultsTwenty-seven patients were included. Fourteen were randomized to treatment with paricalcitol. There was no difference in peritoneal transport parameters between the groups. We found similar Kt/V, D/P creatinine, D/D0 glucose, ultrafiltration, residual renal function and 24-h urine volume during the study. There was no difference in biomarker concentrations in peritoneal effluents, and no difference in leucocyte differentiation or mesothelial cells between the groups at any time point. Parathyroid hormone (PTH) levels decreased after administration of calcitriol after 12 and 24 weeks compared with baseline ( p = 0.001; p = 0.025). Parathyroid hormone levels in the paricalcitol group did not change significantly.ConclusionIn this pilot study we investigated the effect of active vitamin D in PD patients. We found no specific benefit of active vitamin D3in vitamin D3-sufficient PD patients. Additional studies in preferably incident patients, with an adequate PTH suppression in the intervention groups and during a longer period, are required to test the beneficial effects of active vitamin D3over no treatment and to investigate whether in 25(OH)D3-deficient PD patients the type of active vitamin D3matters.

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