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Goffin E, Becker D, Lievens M. Discrepancy between Measured and Pd Adequest-Calculated Albumin Loss. Perit Dial Int 2020. [DOI: 10.1177/089686089701700424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
| | | | - M.M. Lievens
- Department of Nephrology Department of Biochemistry Louvain Medical School 1200 Brussels, Belgium
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2
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Abstract
Four mathematical models and for the description of peritoneal transport of fluid solutes are reviewed. The membrane model is usually applied for (1) separation of transport components, (2) formulation of the relationship between flow components and their driving forces, and (3) estimation of transport parameters. The three-pore model provides correct relationships between various transport parameters and demonstrates that the peritoneal membrane should be considered heteroporous. The extended threepore model discriminates between heteroporous capillary wall and tissue layer, which are assumed to be arranged in series; the model improves and modifies the results of the three-pore model. The distributed model includes all parameters involved in peritoneal transport and takes into account the real structure of the tissue with capillaries distributed at various distances from the surface of the tissue. How the distributed model may be applied for the evaluation of the possible impact of perfusion rate on peritoneal transport, as recently discussed for clinical and experimental studies, is demonstrated. The distributed model should provide theoretical bases for the application of other models as approximate and simplified descriptions of peritoneal transport. However, an unsolved problem is the theoretical description of bi-directional fluid transport, which includes ultrafiltration to the peritoneal cavity owing to the osmotic pressure of dialysis fluid and absorption out of the peritoneal cavity owing to hydrostatic pressure.
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Affiliation(s)
- Jacek Waniewski
- Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland, and Divisions of Baxter Novum and Renal Medicine, Department of Clinical Sciences, Huddinge University Hospital, Karolinska Institute, Stockholm, Sweden
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Amici G, Viglino G, Virga G, Gandolfo C, Da Rin G, Bocci C, Cavalli PL. Compliance Study in Peritoneal Dialysis Using Pdadequest Software. Perit Dial Int 2020. [DOI: 10.1177/089686089601601s33] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Poor compliance in peritoneal dialysis (PD) is a significant cause of dropout and morbidity. PD Adequest software, which, through a mathematical model, predicts the effect of the dialysis prescription on the basis of the peritoneal transport, may be used to identify the noncompliant patient. Fifty patients from two dialysis centers, aged 65.9±1.5 years and on PD for 28.6±4.7 months, were studied. A peritoneal equilibration test (PET) was carried out and 24hour urine and dialysate were collected. Total weekly creatinine clearance (CrCI, L/week/1.73 m2) was calculated, as well as the glomerular filtration rate [(GFR), mL/min, mean CrCI and urea nitrogen clearance (UNCI)]. The dialytic schedules used were then introduced into the program and the parameters were recalculated using the software model. Nine patients considered noncompliant from their case histories were used to assess the differences of reference between expected and measured values. The control group was significantly different from the noncompliant group in the percentage of the CrCI and the serum creatinine (sCR) differences. The noncompliance threshold value was calculated from the mean of the lower 95% confidence interval of the compliant group and the higher one of the noncompliant group (-5.3%) for CrCI and vice versa for sCR (+10%), which behaved to the contrary. Reassessing the patients, 11 (22%) were identified as probably noncompliant.
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Affiliation(s)
- Gianpaolo Amici
- Nephrology Division and Laboratory,’ Regional Hospital “S. Maria dei Battuti,” Treviso
| | | | | | | | - Giorgio Da Rin
- Nephrology Division and Laboratory,’ Regional Hospital “S. Maria dei Battuti,” Treviso
| | - Carlo Bocci
- Nephrology Division and Laboratory,’ Regional Hospital “S. Maria dei Battuti,” Treviso
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Keshaviah P. Establishing Kinetic Guidelines for Peritoneal Dialysis Modality Selection. Perit Dial Int 2020. [DOI: 10.1177/089686089701703s15] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Blake P, Burkart JM, Churchill DN, Daugirdas J, Depner T, Hamburger RJ, Hull AR, Korbet SM, Moran J, Nolph KD, Oreopoulos DG, Schreiber M, Soderbloom R. Recommended Clinical Practices for Maximizing Peritoneal Dialysis Clearances. Perit Dial Int 2020. [DOI: 10.1177/089686089601600507] [Citation(s) in RCA: 124] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Data from the Canada-U.S.A. (CANUSA) Study have recently confirmed a long-suspected linkage between total clearance and patient survival in peritoneal dialysis (PD). Recognizing that what we have historically accepted as adequate PD simply is not, the Ad Hoc Committee on Peritoneal Dialysis Adequacy met in January, 1996. This committee of invited experts was convened by Baxter Healthcare Corporation to prepare a consensus statement that provides clinical recommendations for achieving clearance guidelines for peritoneal dialysis. Through an analysis of 806 PD patients, the group concluded that adequate clearance delivered with PD can be achieved in almost all patients if the prescription is individualized according to the patient's body surface area, amount of residual renal function, and peritoneal membrane transport characteristics. Use of 2.5 L to 3.0 L fill volumes, the addition of an extra exchange, and giving automated peritoneal dialysis patients a “wet” day are all options to consider when increasing weekly creatinine clearance and KTN. Rather than specify a single clearance or KTN target, the recommended clinical practice is to provide the most dialysis that can be delivered to the individual patient, within the constraints of social and clinical circumstances, quality of life, life-style, and cost. The challenge to PD practitioners is to make prescription management an integral part of everyday patient management. This includes assessment of peritoneal membrane permeability, measurement of dialysis and residual renal clearance, and adjustment of the dialysis prescription when indicated.
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Affiliation(s)
| | - John M. Burkart
- Bowman Gray School of Medicine, Winston-Salem, North Carolina,
| | | | | | | | | | - Alan R. Hull
- University of Texas Southwestern Medical Center, Dallas, Texas
| | | | - John Moran
- Baxter Healthcare Corporation, 10 McGaw Park, Illinois
| | | | | | | | - Robert Soderbloom
- Lorna Linda University School of Medicine, Loma Linda, California, U.S.A
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Jenkins SB, Wilkie ME. An Exploratory Study of a Novel Peritoneal Combination Dialysate (1.36% Glucose/7.5% Icodextrin), Demonstrating Improved Ultrafiltration Compared to Either Component Studied Alone. Perit Dial Int 2020. [DOI: 10.1177/089686080302300513] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Objective Concerns regarding the impact of ultrafiltration failure on peritoneal dialysis and the effect of hypertonic glucose on the peritoneal membrane have lead to a search for alternative dialysates. Computer simulations based on the three-pore theory suggest that a combination of 1.36% glucose and 7.5% icodextrin (glucose polymer) offers an improved ultrafiltration profile. The aim of the present study was to investigate the ultrafiltration profile of this combination fluid. Design Prospective open study comparing 1.36% glucose, 3.86% glucose, 7.5% icodextrin, and the combination fluid (1.36% glucose/7.5% icodextrin). Setting Sheffield Kidney Institute, Northern General Hospital, Sheffield, UK. Patients 11 patients currently using peritoneal dialysis not previously exposed to icodextrin. Main Outcome Measure Intraperitoneal volume was measured using a radioisotope dilution method. Results The combination fluid showed a biphasic ultrafiltration profile, with a steep initial increase in intraperitoneal volume, then a maintained plateau phase for the duration of the study dwell (7 hours). The final volume was greater than that with the 1.36% glucose dwell and the 7.5% icodextrin dwell. The fluid was well tolerated by the patients. Conclusions These findings are in keeping with computer simulations using the three-pore model. The combination fluid offers an improved ultrafiltration profile, with a final volume similar to 3.86% glucose, while avoiding exposing the peritoneal membrane to high glucose concentrations. It may have a role as a long dwell to optimize ultrafiltration and possibly prolong peritoneal dialysis technique survival.
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Affiliation(s)
- Sarah B. Jenkins
- Sheffield Kidney Institute, Northern General Hospital, Sheffield University Hospital Trust, Sheffield, South Yorkshire, United Kingdom
| | - Martin E. Wilkie
- Sheffield Kidney Institute, Northern General Hospital, Sheffield University Hospital Trust, Sheffield, South Yorkshire, United Kingdom
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Zakaria ELR, Rippe B. Peritoneal Fluid and Tracer Albumin Kinetics in the Rat. Effects of Increases in Intraperitoneal Hydrostatic Pressure. Perit Dial Int 2020. [DOI: 10.1177/089686089501500206] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objectives To study the peritoneal fluid loss rate, the clearance (CI) of radioactive tracer albumin (RISA) eliminated from the peritoneal cavity (PC), as well as the peritoneal-to-plasma RISA clearance (CI -+ P) during acute peritoneal dialysis (PD) at large elevations in intraperitoneal hydrostatic pressure (IPP). Design Experimental study in anesthetized Wistar rats. Methods The intraperitoneal volume (IPV) was assessed using RISA dilution, correcting for the RISA CI from the PC. Volume recovery at termination of the dwells was obtained using graduated cylinders and preweighed gauze tissues. Measurements of CI and CI -+ P were obtained by repeated micro-sampling of dialysate and plasma, respectively. The IPP was continuously measured, and could be varied by external concentric abdominal compression using an inflatable cuff. On termination of the experiments, samples from tissues lining the PC were analyzed with respect to their content of RISA and edema, the latter being assessed from wet/dry weight ratios. Results At 2 mm Hg of IPP (control) the RISA CI was 27.1:1:2.0(:1:SE)μL.min-l, whereas CI→ Pwasonly 8.07:1:0.67 μL.min-l, at a total fluid loss rate of 10.1:1:5.4μL.min-1 for 1.36% Dianeal. At an IPP of 14 mm Hg, the CI increased to 55.3±4.1 μL.min -1 and the peritoneal fluid absorption rate was 34.4±5.6 μL.min -l, whereas CI -+ P was just moderately increased as compared to control (11.2:1:1.4 μL. min -I). Furthermore, a pleural effusion of 1.16:1:0.08 mL was detectable at elevated IPPs. The degree of edema formation in the anterior abdominal muscles (AAM) and the diaphragm (DIA) was largely insignificant during 150 min at 2 mm Hg of IPP, but increased markedly at 14 mm Hg, as did the RISA uptake to the AAM and DIA. The discrepancy between CI and CI -+ P was largely accounted for by tracer entrance into tissues lining the peritoneal cavity, mainly the AAM. Conclusions At a nearly unchanging capillary Starling equilibrium, the losses of fluid and of RISA from the PC were markedly elevated at increased IPPs. However, the RISA clearance to the plasma appeared to be only moderately altered at elevated IPP and represented only a minor fraction of the RISA clearance out of the PC. Tissues lining the PC apparently act as a variable ‘sink’ for intraperitoneal proteins and fluid during peritoneal dialysis (PD).
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Affiliation(s)
- EL Rasheid Zakaria
- Departments of Nephrology and Physiology, University Hospital of Lund, S-221 85 Lund, Sweden
| | - Bengt Rippe
- Departments of Nephrology and Physiology, University Hospital of Lund, S-221 85 Lund, Sweden
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8
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Affiliation(s)
- Bengt Rippe
- Department of Nephrology, University Hospital of Lund, Lund, Sweden
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9
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Ronco C, Kliger AS, Amici G, Virga G. Automated Peritoneal Dialysis: Clinical Prescription and Technology. Perit Dial Int 2020. [DOI: 10.1177/089686080002002s14] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Claudio Ronco
- Renal Research Institute, Division of Nephrology and Hypertension, Beth Israel Medical Center, Albert Einstein College of Medicine, New York, U.S.A
| | - Alan S. Kliger
- Renal Research Institute, Yale University School of Medicine, New Haven, Connecticut, U.S.A
| | - Gianpaolo Amici
- Nephrology Division, S. Maria dei Battuti Hospital, Treviso, Italy
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Burkart JM, Tzamaloukas AH, Bunting D. A 100-kg Man on Peritoneal Dialysis (PD) with a Borderline Kt/V: To PD or Not to PD. Perit Dial Int 2020. [DOI: 10.1177/089686080302300220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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11
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Parry RG, Johnson DW, Carey DG, Hibbins M, Chang W, Purdie D, Rigby RJ. Serum Leptin Correlates with Fat Mass but not Dietary Energy Intake in Continuous Ambulatory Peritoneal Dialysis Patients. Perit Dial Int 2020. [DOI: 10.1177/089686089801800603] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objectives In view of previous studies demonstrating hyperleptinemia in uremic and hemodialysis patients, the aims of the present study were to determine whether serum leptin levels are elevated in peritoneal dialysis (PD) patients, to establish whether leptin is significantly removed by PD, and to elucidate the relationship of plasma leptin to body composition, dietary intake, nutritional indices, and dialysis adequacy. Design Cross-sectional analysis of PD patients and matched healthy controls. Setting Tertiary-care institutional dialysis center. Participants The study included 49 PD patients [35 women and 14 men; median age 63 years, interquartile range (IQR) 49.5 -68.5 yr; body mass index (BMI) 25.5: I: 0.8] and 27 controls (11 men and 16 women; median age 42 years, IQR 34.8 51; BMI 27.2: I: 0.9). For evaluation of leptin clearance, 8 patients receiving nocturnal intermittent PD were also evaluated. Main Outcome Measures The primary outcome measure was plasma leptin concentration. Dialysate leptin concentration was also measured in 7 patients. Results Serum leptin levels were significantly higher (p < 0.01) in patients (males: median 11 nglmL, IQR 9 19 ng/mL; females: 53 ng/mL, 19.5 -128 ng/mL) compared with controls (males: 5.5 nglmL, 4 9.5 nglmL; females: 12 ng/mL, 9.8 17.3 ng/mL). Leptin levels in both groups correlated positively with BMI (r = 0.64 and 0.60, respectively; p < 0.0001) and with percentage body fat determined by dual-energy x-ray absorptiometry (r = 0.86 and 0.82, respectively; p < 0.01). Dialysis patients exhibited a greater increase in serum leptin for any given increase in BMI. No significant correlation was observed between leptin concentration and residual renal function, dialysis adequacy (Kt/V), dietary protein or caloric intake, or serum levels of albumin, prealbumin, C-reactive protein, glucose, and insulin-like growth factor-1. Although leptin was detectable in peritoneal dialysate after a 6-hour dwell (median 4.2 ng/ mL, IQR 1.1 -8.5 ng/mL, n = 8), serum leptin levels were not appreciably lowered following intermittent PD via an automated cycler (63.9: I: 19.3 ng/mL vs 57.6: I: 20.5 ng/mL, p = NS, n = 8). Conclusions Serum leptin levels are elevated in PD patients and are not appreciably cleared by PD. Although hyperleptinemia correlates poorly with dialysis adequacy and protein intake, a strong and significant relationship was maintained between serum leptin and fat mass. Serum leptin could therefore serve as a useful clinical marker of body fat content in PD patients.
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Affiliation(s)
| | | | - David G. Carey
- Endocrinology, and Social and Preventative Medicine, Queensland, Australia
| | - Mark Hibbins
- Departments of Nephrology, Queensland, Australia
| | - Wendy Chang
- Departments of Nephrology, Queensland, Australia
| | - David Purdie
- Princess Alexandra Hospital, Brisbane, Queensland, Australia
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12
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Tzamaloukas AH, Servilla KS, Murata GH, Hoffman RM. Nutrition Indices in Obese Continuous Peritoneal Dialysis Patients with Inadequate and Adequate Urea Clearance. Perit Dial Int 2020. [DOI: 10.1177/089686080202200410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
♦ Objective To test whether better nutrition is associated more with adequate urea clearance than with inadequate urea clearance in obese patients on continuous peritoneal dialysis (CPD). ♦ Design Retrospective analysis of clearance and nutrition indices in obese CPD patients. Only obese patients were analyzed. Obesity was defined as a ratio of actual weight to desired weight (W/DW) ≥ 1.2. The dose of dialysis was considered adequate at weekly Kt/V urea ≥ 2.0. Small solute clearances and nutrition indices were compared between patients with weekly Kt/V urea < 2.0 and patients with weekly Kt/V urea ≥ 2.0 at the first clearance study. ♦ Setting Four university-affiliated and two private dialysis units in Canada and the United States. ♦ Patients A total of 270 CPD patients with W/DW ≥ 1.2 at the first clearance study. ♦ Results Among the 270 obese CPD patients, 157 (58.1%) were underdialyzed (weekly Kt/V urea 1.66 ± 0.22) and 113 (41.9%) had adequate dialysis (weekly Kt/V urea 2.51 ± 0.47) at the first clearance study. Creatinine clearance values also differed between the underdialyzed and adequately dialyzed obese groups (55.6 ± 15.2 vs 87.6 ± 29.8 L/1.73 m2 weekly, respectively, p < 0.001). The underdialyzed group contained fewer women (39.5% vs 60.2%, p < 0.001) and more patients with anuria (35.0% vs 8.8%, p < 0.001), and had higher serum urea (20.7 ± 6.9 vs 18.2 ± 5.3 mmol/L, p = 0.001) and serum creatinine (974 ± 283 vs 734 ± 275 μmol/L, p < 0.001), marginally lower serum albumin (35.8 ± 5.2 vs 37.2 ± 6.4 g/L, p = 0.082), lower urea nitrogen excretion (5778 ± 2290 vs 7085 ± 2238 mg/24 hr, p < 0.001) and indices derived from urea nitrogen excretion (protein nitrogen appearance and normalized protein nitrogen appearance), and lower creatinine excretion (1034 ± 349 vs 1217 ± 432 mg/24 hr, p < 0.001) and indices derived from creatinine excretion (lean body mass normalized to actual or desired weight) than the adequately dialyzed group. ♦ Conclusion Nutrition indices derived from urea nitrogen and creatinine excretion are worse in underdialyzed than in adequately dialyzed obese CPD patients. This finding may have clinical importance, despite the mathematical coupling between small solute clearances and excretion rates in cross-sectional studies, because of evidence from other studies that small solute excretion rate in cross-sectional studies is a robust independent predictor of outcome in CPD.
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Affiliation(s)
| | - Karen S. Servilla
- Renal Section; General Internal Medicine Section, Albuquerque, New Mexico, USA
| | - Glen H. Murata
- New Mexico Veterans Affairs Health Care System and University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
| | - Richard M. Hoffman
- New Mexico Veterans Affairs Health Care System and University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
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Affiliation(s)
- Gianpaolo Amici
- Nephrology Division, S. Maria dei Bat tu ti Hospital, Treviso;, Vicenza, Italy
| | - Giovambattista Virga
- Nephrology Division, Nephrology Service, P. Cosma Hospital, Camposampiero;, Vicenza, Italy
| | - Claudio Ronco
- Nephrology Division, Nephrology Department, S. Bortolo Hospital, Vicenza, Italy
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Rodby RA, Firanek CA, Sarpolis AL. Re-Evaluation of Solute Transport Groups Using the Peritoneal Equilibration Test. Perit Dial Int 2020. [DOI: 10.1177/089686089901900506] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective To determine if the previously described peritoneal equilibration test (PET)-determined solute transport groups, as defined by Twardowski, fit our patient population. Design We reviewed the 195 initial standardized PETs (on 195 patients) performed through our peritoneal dialysis program since 1989. Using the method originally defined by Twardowski using the means and standard deviations of the PET-determined dialysis/plasma ratio (D/P) of creatinine and dialysate-to-0 hour dialysate (D/D0) glucose values, transport groupings for our patient population were determined. Comparisons were then made between patient populations. Results The mean 4-hour D/P creatinine in our patients was 0.70 ± 0.10. This compares to a mean of 0.65 ± 0.15 as determined by Twardowski, and indicates that our patients have higher mean solute transport characteristics and tighter ranges within transport groups than previously reported. Only 2% of our patients fell into the previously described low (L) range, with 30% low average (LA), 51% high average (HA), and 17% high (H). Using our data, we would redefine the groups by a 4-hour D/P creatinine as L < 0.60, LA = 0.60 – 0.70, HA = 0.70 – 0.80, and HA > 0.80. Using these values, our population fits a Gaussian distribution with 17% L, 31% LA, 33% HA, and 19% H. Conclusion Our patients have higher mean solute transport and tighter ranges within transport groups than previously reported. Using the previously defined PET-determined transport groupings, low transporters are particularly underestimated. If our population data are representative of the peritoneal dialysis population as a whole, these ranges should be redefined.
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15
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Jones MR, Gehr TW, Burkart JM, Hamburger RJ, Kraus AP, Piraino BM, Hagen T, Ogrinc FG, Son MW. Replacement of Amino Acid and Protein Losses with 1.1% Amino Acid Peritoneal Dialysis Solution. Perit Dial Int 2020. [DOI: 10.1177/089686089801800211] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective Losses of nutrients into dialysate may contribute to malnutrition. Peritoneal dialysis (PD) patients are reported to lose 3 -4 g/day of amino acids (AAs) and 4 -15 g/day of proteins. The extent to which one exchange with a 1.1% AA dialysis solution (Nutrineal, Baxter, Deerfield, IL, U.s.A.) offsets these losses was investigated in a 3-day inpatient study in 20 PD patients. Design Simple, open-label, cross-over study on consecutive days in a clinical research unit. On day 1 all patients were given a peritoneal equilibration test (PET). On day 2 they received 1.5% dextrose Dianeal (Baxter) as the first exchange of the day and their usual regimen thereafter. On day 3, the first exchange of the day was the 1.1% AA solution in place of 1.5% Dianeal and the usual PD regimen thereafter. On days 2 and 3 all dialysate effluent was collected and analyzed for AAs and proteins. Patients were maintained on a constant diet. Results Losses of AAs and total proteins on day 2 were 3.4 ± 0.9 g and 5.8 ± 2.4 g, respectively, totaling 9.2 ± 2.7 g. The net uptake of AAs on day 3 was 17.6 ± 2.6 g (80 ± 12% of the 22 g infused). Mean gains of AAs on day 3 exceeded losses of proteins and AAs on day 2, p < 0.001. Losses of total proteins, but not losses of AAs, and the net absorption of AAs from the dialysis solution were correlated directly with peritoneal membrane transport characteristics, obtained from the PET. Conclusion Daily losses of AAs and proteins into dialysate are more than offset by gains of AAs absorbed from one exchange with 1.1% AA-based dialysis solution. Net gains of AAs exceeded losses of proteins and AAs in all patients studied. The difference was relatively constant across a wide range of membrane transport types. Net AA gains were approximately two times the total AA and protein losses.
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Affiliation(s)
| | - Todd W. Gehr
- MCV Hospitals of Virginia Commonwealth University; Richmond, Virginia
| | - John M. Burkart
- Bowman Gray School of Medicine, Winston-Salem, North Carolina
| | | | | | | | - Tricia Hagen
- Baxter Healthcare Renal Division, McGaw Park, Illinois
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16
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Hölttä TM, Rönnholm KA, Holmberg C. Influence of Age, Time, and Peritonitis on Peritoneal Transport Kinetics in Children. Perit Dial Int 2020. [DOI: 10.1177/089686089801800606] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objective To evaluate peritoneal transport kinetics and its changes over time in children with and without peritonitis, and to record possible differences between children under and over 5.0 years of age. Design A prospective study. The patients underwent a 4hour peritoneal equilibration test (PET) comprising 2.27% dextrose with a dialysate fill volume of 1000 mL/m2 of body surface area (BSA), at baseline and after a mean of 0.8: I: 0.4 years of uninterrupted dialysis. Patients We investigated 28 patients on maintenance peritoneal dialysis at baseline; 10 were under 5.0 years of age. The final PET was performed in 21 patients. Main Outcome Measures Peritoneal equilibration rates for urea (U), creatinine (C), glucose (G), sodium, potassium, phosphate, and albumin (A) were measured. Initial and final peritoneal equilibration rates were compared. Mass transfer area coefficients (MTAC) were calculated for urea, creatinine, glucose, and albumin. Residual dialysate volume was determined. Results Median age at first PET was 7.6 years (range 0.3 -16.6 yr). The mean (±1 SD) 4-hour dialysate-to-plasma (DIP) ratios for U, C, and A were 0.92:1: 0.05,0.70 ± 0.12, and 0.014: I: 0.007, respectively. The mean 4-hour DIDo ratio for G was 0.32: I: 0.10. DIP and DIDo results were similar in the two age groups, and peritoneal membrane function remained stable over the study period. Mean MTAC (:1:1 SD) values were: U, 22.3: I: 4.8; C, 10.9: I: 4.1; G, 11.1: I: 3.3; and A, 0.07: I: 0.03. MTAC data were similar in the two age groups and no significant changes occurred during the study period. Conclusions When the volume tested in children is proportional to BSA, the solute DIP ratios seem to be age-independent. Our data provide evidence that in pediatric patients MTAC is also age-independent.
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Affiliation(s)
- Tuula M. Hölttä
- Pediatric Nephrology and Transplantation, Hospital for Children and Adolescents, University of Helsinki, Helsinki, Finland
| | - Kai A.R. Rönnholm
- Pediatric Nephrology and Transplantation, Hospital for Children and Adolescents, University of Helsinki, Helsinki, Finland
| | - Christer Holmberg
- Pediatric Nephrology and Transplantation, Hospital for Children and Adolescents, University of Helsinki, Helsinki, Finland
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17
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Affiliation(s)
- Gianpaolo Amici
- Nephrology and Dialysis Division, Regional Hospital S. Maria dei Battuti, Treviso, Italy
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18
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Abstract
The three-pore model of peritoneal transport treats the capillary membrane as a primary barrier determining the amount of solute that transports to the interstitium and the peritoneal cavity. According to the three-pore model, the principal peritoneal exchange route for water and water-soluble substances is a protein-restrictive pore pathway of radius 40–55 A, accounting for approximately 99% of the total exchange (pore) area and approximately 90% of the total peritoneal ultrafiltration (UF) coefficient (LpS). For their passage through the peritoneal membrane proteins are confined to so-called “large pores” of radius approximately 250 Å, which are extremely few in number (0.01% of the total pore population) and more or less nonrestrictive with respect to protein transport. The third pathway of the three-pore model accounts for only about 2% of the total LpS and is permeable to water but impermeable to solutes, a so-called “water-only” (transcellular?) pathway. In contrast to the classical Pyle-Popovich (P&P) model, the three-pore model can predict with reasonable accuracy not only the transport of water and “small solutes” (molecular radius 2.3–15 Å) and “intermediatesize” solutes (radius 15–36 Å), but also the transport of albumin (radius 36 Å) and larger molecules across the peritoneal membrane. The model operates with reflection coefficientsa (a's) for small solutes <0.1. These are approximately one order of magnitude lower than the & sigma's In the P&P model. Furthermore, the peritoneal LPS is one order of magnitude higher than In the P&P model. As a consequence, the major portion of the “fluid loss” from the peritoneal cavity In continuous ambulatory peritoneal dialysis (CAPD) can be explained by the operation of the so-called Starling forces (the transcapillary hydrostatic pressure gradient opposed by the plasma colloid osmotic pressure as multiplled by the LpS), and to a much lesser extent by lymphatic absorption (L). Furthermore, In contrast to the P&P model, the three-pore model can with reasonable accuracy predict the UF profiles produced when glucose Is substituted by high molecular weight solutes as osmotic agents In CAPO.
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Affiliation(s)
- Bengt Rippe
- Department of Nephrolog, University Hospital of Lund, Lund, Sweden
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Vonesh EF, Burkart J, McMurray SD, Williams PF. Peritoneal Dialysis Kinetic Modeling: Validation in a Multicenter Clinical Study. Perit Dial Int 2020. [DOI: 10.1177/089686089601600509] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective To clinically validate the use of a computer-based kinetic model for peritoneal dialysis (PD) by assessing the level of agreement between measured and modeled values of urea and creatinine clearances and ultrafiltration (UF). Design An open multicenter observational study. Patients There were 111 adult continuous ambulatory peritoneal dialysis (CAPD) patients (47 female, 64 male) in four centers. All patients underwent a four-hour peritoneal equilibration test (PET) using 2.5% dextrose but with variable fill volumes (range: 1 -3 L). Patients with a residual renal function greater than 10 mL/min were excluded. Main Outcome Measures Correlations and limits of agreement between measured and modeled values of total weekly urea KTN, total weekly normalized creatinine clearance (L/week/1.73 m2), daily drain volume (L), net ultrafiltration (L), daily peritoneal urea clearance (L/day), and daily peritoneal creatinine clearance (L/day). Measured values were obtained from 24-hour urine and dialysate collections while modeled values were based on results from the PET in combination with the PD ADEQUEST® kinetic program. Results The results show there is excellent agreement between measured and modeled urea KTN and creatinine clearances, with concordance correlations of 0.94 and 0.92, respectively. Given the excessive variation and limited range in ultrafiltration values, the concordance correlation between measured and modeled UF was only 0.50. In terms of daily peritoneal clearances and ultrafiltration, the level of precision (i.e., standard deviation) in the differences between modeled and measured values is ±1.05 L/ day for urea clearance, ±1.03 L/day for creatinine clearance, and ±0.919 L/day for ultrafiltration. By contrast, the level of precision (i.e., standard deviation) in the differences between two measured values is estimated to be ±0.979 L/day for urea clearance, ±0.802 L/day for creatinine clearance, and ±0.707 L/day for ultrafiltration. Defining the limits of clinical agreement to be ±2 standard deviations of the differences between two clinically measured 24-hour clearances (or ultrafiltration), we find that 94% of the modeled urea clearances, 87% of the modeled creatinine clearances, and 86% of the modeled ultrafiltration values fall within the limits of clinical agreement. Conclusion Data from a carefully performed PET and overnight exchange can, in combination with a scientifically validated kinetic model, provide clinicians with a powerful mathematical tool for use in CAPD dialysis prescription management. Although not intended to replace actual measurements, kinetic modeling can prove useful as a means for predicting clearances for various alternative prescriptions and perhaps also as a means for checking certain types of noncompliance.
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Affiliation(s)
- Edward F. Vonesh
- Applied Statistics Center, Baxter Healthcare Corporation, Round Lake, Illinois,
| | - John Burkart
- Bowman Gray School of Medicine, Winston-Salem, North Carolina
| | - Stephen D. McMurray
- Northeast Indiana Kidney Center, Renal Care Group, Fort Wayne, Indiana, U.S.A
| | - Paul F. Williams
- Addenbrooke's Hospital, Cambridge, and Ipswich Hospital, Ipswich, England
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Affiliation(s)
- Edward F. Vonesh
- Baxter Healthcare Corporation, Applied Statistics Center, Round Lake, Illinois
| | - Prakash R. Keshaviah
- Baxter Healthcare Corporation, Clinical Engineering Laboratory, Minneapolis, Minnesota, U.S.A
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Affiliation(s)
- Claudio Ronco
- Department of Nephrology, St. Bortolo Hospital, Vicenza, Italy
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Vonesh EF, Story KO, O'Neill WT. A Multinational Clinical Validation Study of Pd Adequest 2.0. Perit Dial Int 2020. [DOI: 10.1177/089686089901900611] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Objective To clinically validate the use of the newly released kinetic modeling program, PD ADEQUEST 2.0 for Windows (Baxter Healthcare Corporation, Deerfield, IL, U.S.A.), by assessing the level of agreement between measured and modeled values of urea and creatinine clearances (CCr), glucose absorption, total drain volumes, and net ultrafiltration for all forms of peritoneal dialysis. Design A nonrandomized, multinational, prospective longitudinal study. Patients The study involved 104 adult patients [41 on continuous ambulatory peritoneal dialysis (CAPD), 63 on automated peritoneal dialysis (APD)] from 16 centers in 7 countries. All patients underwent a 4-hour peritoneal equilibration test (PET) but with varying percentage dextrose concentrations (1.5% or 2.5% dextrose) and varying fill volumes (range 1.5 – 2.5 L). Patients with a residual renal function greater than 10 mL/min were excluded, as were patients who had peritonitis within 6 weeks prior to baseline. Main Outcome Measures Correlation coefficients and Bland–Altman limits of agreement were used to assess the level of agreement between measured and modeled values of weekly peritoneal urea Kt/V (pKt/V) and total Kt/V, weekly peritoneal creatinine clearance (pCCr, L/week/ 1.73 m2) and total CCr (L/week/1.73 m2), daily drain volume (L/day), net ultrafiltration (UF, L/day), daily peritoneal urea and creatinine mass removal (g/day), and daily peritoneal glucose absorption (g/day). Measured values were obtained from three repeat 24-hour urine and dialysate collections per patient, while modeled values were calculated using the Baxter PD ADEQUEST 2.0 program in conjunction with kinetic parameters estimated from a 4-hour PET and long-dwell exchange independent of the 24-hour collections. Results The results show there is excellent agreement between measured and modeled urea Kt/V and CCr with concordance correlation coefficients ranging from 0.83 to 0.97 among CAPD and APD patients. There was also excellent agreement between measured and modeled values of glucose absorption and total drain volumes (concordance correlations of 0.90 and 0.98, respectively). This level of agreement was further supported by a Bland– Altman analysis of individual differences, including differences between measured and modeled net UF (coefficient of clinical agreement ranged from 0.66 to 0.92). Conclusions Data from a carefully performed PET and overnight exchange can, in combination with a scientifically and clinically validated kinetic model, provide clinicians with a powerful mathematical tool for use in CAPD and APD prescription management. Although not intended to replace actual measurements, kinetic modeling can prove useful as a means for quickly estimating approximate levels of clearance for a wide variety of alternative prescriptions. This, in turn, should speed up the process by which a physician can optimize the dose of dialysis suitable for a given patient and his/her lifestyle.
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Affiliation(s)
| | - Edward F. Vonesh
- Applied Statistics Center, Baxter Healthcare Corporation, Round Lake, Illinois, U.S.A
| | - Kenneth O. Story
- Applied Statistics Center, Baxter Healthcare Corporation, Round Lake, Illinois, U.S.A
| | - William T. O'Neill
- Applied Statistics Center, Baxter Healthcare Corporation, Round Lake, Illinois, U.S.A
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Affiliation(s)
- Gianpaolo Amici
- Carlo Bocci Nephrology and Dialysis Division Laboratory Regional Hospital “S. Maria dei Battuti” Treviso, Italy
| | - Giorgio Da Rin
- Carlo Bocci Nephrology and Dialysis Division Laboratory Regional Hospital “S. Maria dei Battuti” Treviso, Italy
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Affiliation(s)
- Bruce Z. Morgenstern
- Section of Pediatric Nephrology, Department of Pediatrics, Mayo Clinic, Rochester, Minnesota, U.S.A
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Waniewski J, Debowska M, Lindholm B. How Accurate is the Description of Transport Kinetics in Peritoneal Dialysis According to Different Versions of the Three-Pore Model? Perit Dial Int 2020. [DOI: 10.1177/089686080802800110] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
ObjectiveThe 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.MethodDetailed 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).ResultsUsing 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.ConclusionThe 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.
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Affiliation(s)
- Jacek Waniewski
- Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland
- Divisions of Baxter Novum and Renal Medicine, Department of Clinical Sciences, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | | | - Bengt Lindholm
- Divisions of Baxter Novum and Renal Medicine, Department of Clinical Sciences, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
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Abstract
Objective To validate the use of a modified three-pore model for predicting fluid transport during long dwell exchanges that use a 7.5% icodextrin solution. Design A nonrandomized, single group, repeated measures study. Patients Ten peritoneal dialysis patients underwent a single 8-hour exchange of a 7.5% icodextrin solution. All patients were naïve to icodextrin. Main Outcome Measures A modified three-pore model was used to model solute and fluid transport during each 8-hour exchange. Concordance correlation coefficients were used to estimate the level of agreement between modeled and measured values of net ultrafiltration (UF) and intraperitoneal volume. Methods Each patient underwent a modified 8-hour standard peritoneal permeability analysis using a 2-L 7.5% icodextrin exchange. Dextran 70 was added to the icodextrin solution as volume marker to estimate fluid transport kinetics. Transcapillary UF, fluid absorption, and intraperitoneal volumes were assessed via the volume marker at 0, 5, 15, 30, 60, 120, 240, 300, 360, 420, and 480 minutes. Results There was strong agreement (concordance correlation = 0.9856) between net UF as measured by the volume marker data and net UF as modeled using the modified three-pore model implemented in PD Adequest (Baxter Healthcare, Deerfield, Illinois, USA). Conclusions Net UF and intraperitoneal volumes for long dwell exchanges using a 7.5% icodextrin solution can be accurately modeled with a modified three-pore model. Steady state icodextrin plasma levels are needed to accurately predict net UF for chronic users of icodextrin.
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Affiliation(s)
| | | | - Caroline E. Douma
- Renal Unit, Academic Medical Center University of Amsterdam, Amsterdam, The Netherlands
| | - Raymond T. Krediet
- Renal Unit, Academic Medical Center University of Amsterdam, Amsterdam, The Netherlands
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Waniewski J, Heimbürger O, Werynski A, Lindholm B. Simple Models for Fluid Transport during Peritoneal Dialysis. Int J Artif Organs 2018. [DOI: 10.1177/039139889601900806] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Peritoneal fluid transport can be predicted using different simplified formulas. To evaluate three such models, fluid transport was studied in 38 single six hour dwell studies using standard glucose 1.36% (n=9), 2.27% (n=9) and 3.86% (n=20) dialysis fluids as well as amino acid 2.70% fluid (n=8) in 33 patients on continuous ambulatory peritoneal dialysis (CAPD). Dialysate volume and the peritoneal absorption rate were measured using radioiodinated serum albumin (RISA) as a marker. The dialysate volume over dwell time curves were examined using three mathematical models of fluid transport for solutions with a crystalloid osmotic agent: Model P based on phenomenologically derived exponential function of time (Pyle, 1981), Model OS based on linear relationship between the rate of net volume change, Qv, to the difference of osmolality in dialysate and blood, and Model G based on linear relationship between Qv and the difference of glucose concentration in dialysate and blood. All these models provided a good description of the measured dialysate volume over time curves, however the descriptions with Models OS and G for glucose 3.86% fluid were slightly but significantly less precise. The coefficients of Model OS were stable in time, but the coefficients of Model G and P dependend in general on the time period used for their estimation, especially for glucose 3.86% dialysis fluid. The evaluation of dwell studies with solutions containing amino acid 2.70% (instead of glucose) as osmotic agent, using Model OS and P, showed that the transport coefficients were stable in time and both models provided equally precise descriptions. These results suggested that all three models can be used but models P and OS can be preferred for pratical applications such as predictions of fluid transport with alternative cristalloid osmotic agents. Furthermore, we found that the peritoneal barrier for fluid transport may change transiently during exchanges with the standard glucose - based dialysis fuid, whereas such changes were not observed with the amino acid-based fluid. This discrepancy may be due to a different composition of the dialysis fluids, including osmotic agent, buffer and pH.
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Affiliation(s)
- J. Waniewski
- Division of Baxter Novum, Department of Clinical Sciences, Huddinge University Hospital, Karolinska Institute, Stockholm - Sweden
- Institute of Biocybernetics and Biomedical Engineering, Warsaw - Poland
| | - O. Heimbürger
- Department of Renal Medicine, Huddinge University Hospital, Karolinska Institute, Stockholm - Sweden
| | - A. Werynski
- Institute of Biocybernetics and Biomedical Engineering, Warsaw - Poland
| | - B. Lindholm
- Division of Baxter Novum, Department of Clinical Sciences, Huddinge University Hospital, Karolinska Institute, Stockholm - Sweden
- Department of Renal Medicine, Huddinge University Hospital, Karolinska Institute, Stockholm - Sweden
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Galach M, Antosiewicz S, Baczynski D, Wankowicz Z, Waniewski J. Sequential peritoneal equilibration test: a new method for assessment and modelling of peritoneal transport. Nephrol Dial Transplant 2013; 28:447-54. [PMID: 23413278 DOI: 10.1093/ndt/gfs592] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND In spite of many peritoneal tests proposed, there is still a need for a simple and reliable new approach for deriving detailed information about peritoneal membrane characteristics, especially those related to fluid transport. METHODS The sequential peritoneal equilibration test (sPET) that includes PET (glucose 2.27%, 4 h) followed by miniPET (glucose 3.86%, 1 h) was performed in 27 stable continuous ambulatory peritoneal dialysis patients. Ultrafiltration volumes, glucose absorption, ratio of concentration in dialysis fluid to concentration in plasma (D/P), sodium dip (Dip D/P Sodium), free water fraction (FWF60) and the ultrafiltration passing through small pores at 60 min (UFSP60), were calculated using clinical data. Peritoneal transport parameters were estimated using the three-pore model (3p model) and clinical data. Osmotic conductance for glucose was calculated from the parameters of the model. RESULTS D/P creatinine correlated with diffusive mass transport parameters for all considered solutes, but not with fluid transport characteristics. Hydraulic permeability (L(p)S) correlated with net ultrafiltration from miniPET, UFSP60, FWF60 and sodium dip. The fraction of ultrasmall pores correlated with FWF60 and sodium dip. CONCLUSIONS The sequential PET described and interpreted mechanisms of ultrafiltration and solute transport. Fluid transport parameters from the 3p model were independent of the PET D/P creatinine, but correlated with fluid transport characteristics from PET and miniPET.
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Affiliation(s)
- Magda Galach
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 02-109 Warsaw, Poland
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IBELS LS, GARCHOW S, MORAN J. Provision of optimal dialysis for peritoneal dialysis patients. Nephrology (Carlton) 2008. [DOI: 10.1111/j.1440-1797.1998.tb00314.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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The contribution of combined crystalloid and colloid osmosis to fluid and sodium management in peritoneal dialysis. Kidney Int 2008:S102-11. [PMID: 18379532 DOI: 10.1038/sj.ki.5002610] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The achievement of euvolemia is essential to the successful management of peritoneal dialysis patients. However, the concern that hypertonic glucose exchanges may have a role in long-term changes to the peritoneal membrane has lead to an alternative strategy to enhance ultrafiltration (UF) over the long dwell by combining crystalloid and colloid osmosis. This review summarizes the experience of mixing glucose or amino acids with polyglucose (icodextrin), with particular focus given to data from studies using glucose/icodextrin in combinations of 1.36%/7.5% and 2.61%/6.8%. Both combinations demonstrate a significant increment of UF volume and sodium removal compared with the component osmotic agents used individually over long dwells, with the 2.61%/6.8% mixture having an effect over dwells extending to 15 h. Hypothetically, the mechanism of the enhanced UF is the attenuation by the colloid osmotic force of the backflow of water through small pores from dialysate to the peritoneal capillary circulation once the crystalloid osmotic force has dissipated. This experience provides promising data that deserves further examination in longer term clinical studies.
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Tzamaloukas AH, Raj DSC, Onime A, Servilla KS, Vanderjagt DJ, Murata GH. The prescription of peritoneal dialysis. Semin Dial 2008; 21:250-7. [PMID: 18248525 DOI: 10.1111/j.1525-139x.2007.00412.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In addition to the maintenance of normal extracellular electrolyte composition, the prescription of continuous peritoneal dialysis (CPD) should address four other specific issues: (i) prevention of uremia by achievement of adequate clearance of azotemic substances, (ii) prevention of progressive expansion of the extracellular volume by adequate peritoneal ultrafiltration, (iii) prevention of loss of residual renal function, and (iv) prevention of deterioration of the peritoneal membrane structure and function. Urea clearance, in the form of Kt/V(Urea), is the index of removal of azotemic substances proposed by current guidelines. The target total (renal plus peritoneal) Kt/V(Urea) is >or=1.7 weekly. To provide the desired peritoneal Kt/V(Urea) (K(p)t/V(Urea)), the prescription of peritoneal dialysis must provide a daily drain volume (Dv) defined by the clearance equations as Dv = V x (K(p)t/V(Urea))/(D/P(Urea)), where V is body water obtained from published anthropometric formulas, K(p)t/V(Urea) = (1.7 - renal Kt/V(Urea))/7 and D/P(Urea) is the dialysate-to-plasma urea concentration ratio at the dwell time prescribed. Computer programs obtain the relevant D/P(Urea) values from formal studies of peritoneal transport. In the absence of these studies (for example, at initiation of CPD), D/P(Urea) values can be obtained from published studies with similar dwell times. Body size, indicated by V, is the major determinant of the K(p)t/V(Urea) limit provided by a given CPD schedule. Other obstacles to achievement of adequate urea clearance are created by poor patient compliance, inaccuracies of the anthropometric formulas estimating V, and mechanical complications of CPD that lead to retention of dialysate in the body. The main requirements for the prescription of adequate ultrafiltration are knowledge of the individual peritoneal transport characteristics, monitoring of urinary volume, and restriction of dietary sodium intake. Excessive dietary sodium intake is the major cause of extracellular volume expansion in CPD. Ideally, sodium intake should be kept at the level of total (peritoneal plus renal) sodium removal. Preventing the loss of residual renal function involves avoidance of nephrotoxic influences in the form of medications, radiocontrast agents, urinary obstruction and infection, and possibly other influences, such an elevated calcium-phosphorus product and anemia. Use of the lowest dialysate dextrose concentration that will allow adequate ultrafiltration is currently the most widespread practical measure of prevention of peritoneal membrane deterioration. Formulation of biocompatible dialysate is a major ongoing research effort and may greatly enhance the success of CPD in the future.
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Affiliation(s)
- Antonios H Tzamaloukas
- Renal Section, Department of Medicine, New Mexico VA Health Care System, 1501 San Pedro, SE, Albuquerque, NM 87108, USA.
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Hamada H, Namoto S, Yamada R, Al Mamun A, Yamashita AC, Ishizaki M, Okamoto M. Development of a computer-aided diagnosis system for continuous peritoneal dialysis: an availability of the simultaneous numerical optimization technique for kinetic parameters in the peritoneal dialysis model. Comput Biol Med 2007; 37:1700-8. [PMID: 17548068 DOI: 10.1016/j.compbiomed.2007.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 02/28/2007] [Accepted: 04/09/2007] [Indexed: 11/21/2022]
Abstract
We developed a novel diagnostic system for continuous peritoneal dialysis, which evaluates the peritoneal permeability and hydraulic conductance (peritoneal function) by applying the kinetic model and a clinical test with minimum nursing time. Kinetic parameters for the peritoneal function were determined by the simultaneous numerical optimization techniques (SNOT). Furthermore dialysis outcome and ultrafiltration volume were estimated and predicted by using the kinetic model with a set of optimal kinetic parameters, which were in agreement with measured data (r(2)>0.82). The clinical implementation of the SNOT is very useful to explore the better prescriptions for each patient's clinical condition.
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Affiliation(s)
- Hiroyuki Hamada
- Laboratory for Bioinformatics, Graduate School of Systems Life Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
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Chou MY, Kao MT, Lai MN, Chung SY. Comparisons of the peritoneal equilibration test and ultrafiltration in patients with and without diabetes mellitus on continuous ambulatory peritoneal dialysis. Am J Nephrol 2006; 26:87-90. [PMID: 16543711 DOI: 10.1159/000092030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Accepted: 01/16/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS To compare dialysance and ultrafiltration (UF) of peritoneum in diabetes mellitus (DM) and non-DM patients on continuous ambulatory peritoneal dialysis. METHODS A total of 162 adult patients on continuous ambulatory peritoneal dialysis (40 DM and 122 non-DM patients) were studied with the peritoneal equilibration test (PET) using 2.5% glucose dialysis solution retained for 4 h. Patients using 2,000 or 1,500 ml of infusion volume were classified into groups A (23 DM and 63 non-DM patients) and B (16 DM and 41 non-DM patients), respectively. PET results were compared between DM and non-DM patients by unpaired t test. Using Pearson's correlation and least-square multiple regression, the most powerful predictors of UF rate were also evaluated in DM and non-DM patients. RESULTS There were no differences between PET parameters and UF rate between DM and non-DM patients in the whole group (WG) and group A. The only significant difference (p < 0.05) was an increased D4/D0 value in DM patients in group B. The most simple but powerful method to predict UF rate was (100 - GAP)/(D4/D0), where GAP corresponds to the glucose absorption percentage and D4/D0 is the PET 4-hour dialysate glucose level/PET 0-hour dialysate glucose level. GAP and D4/D0 were two major determinants of UF rate in the DM group, non-DM group and WG. CONCLUSIONS Peritoneal permeability did not differ between DM and non-DM patients, and GAP and D4/D0 were two major factors predicting UF rate.
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Affiliation(s)
- Ming-Yen Chou
- Division of Nephrology, Department of Medicine, China Medical University Hospital, Taichung, Taiwan, ROC.
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Waniewski J. Mathematical modeling of fluid and solute transport in hemodialysis and peritoneal dialysis. J Memb Sci 2006. [DOI: 10.1016/j.memsci.2005.11.038] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Hamada H, Namoto S, Yamada R, Yamashita AC, Ishizaki M, Okamoto M. Development of a computer-aided diagnosis system for a new modality of renal replacement therapy: an integrated approach combining both peritoneal dialysis and hemodialysis. Comput Biol Med 2005; 35:845-61. [PMID: 16310010 DOI: 10.1016/j.compbiomed.2004.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2003] [Revised: 09/10/2004] [Accepted: 09/10/2004] [Indexed: 10/26/2022]
Abstract
The authors developed a computer-aided diagnosis system that includes a simple clinical test for the chronic renal disease patient who needs an integrated approach that combines both peritoneal dialysis and hemodialysis (PD-HD therapy). In this case study, the system simulated and estimated the dialysis outcome, the ultrafiltration volume and nutritional analysis by employing a pharmacokinetic model, and assessed the peritoneal permeable enhancement that can be a grave complication with peritoneal dialysis. This system requires only a minimum amount of nursing time and may be able to predict the optimal treatment schedule for PD-HD therapy and provide therapeutic monitoring in long-term peritoneal dialysis.
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Affiliation(s)
- Hiroyuki Hamada
- Laboratory for Bioinformatics, Graduate School of Systems Life Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan.
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Abstract
Optimization of the peritoneal dialysis (PD) prescription includes attempts to normalize the patient's blood pressure and extracellular volume. To do so, one must utilize crystalloid or colloid osmotic agents to achieve ultrafiltration. These osmotic agents are systemically absorbed and thus have both potential benefits and adverse effects. With glucose-based dialysate solutions, the average patient absorbs 300-450 kcal of glucose per day on either continuous ambulatory peritoneal dialysis (CAPD) or the cycler. The amount of glucose absorbed varies based on peritoneal transport characteristics, prescription, and tonicity of fluids used. Alternative osmotic agents such as amino acids and macromolecular solutions, including polypeptides and polyglucose (icodextrin) solutions, have a different rate of systemic absorption and thus a different caloric load profile. In addition, there are protein losses that average about 10 g/day with glucose-based solutions and glucose losses with either amino acid or icodextrin dialysate solutions. There are also potential advantages of these alternative solutions with regard to ultrafiltration. Glucose-based solutions require the development of significant crystalloid osmotic forces, which are dissipated as glucose is absorbed systemically. In contrast, macromolecular solutions achieve ultrafiltration via differences in colloid osmotic pressure, and the absorption of these agents is of a lesser magnitude than glucose-based solutions. Further research is needed to determine other potential risks and benefits of these alternative dialysate solutions.
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Affiliation(s)
- John Burkart
- Department of Internal Medicine, Section on Nephrology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1053, USA.
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Liao Z, Zhang W, Hardy PA, Poh CK, Huang Z, Kraus MA, Clark WR, Gao D. Kinetic comparison of different acute dialysis therapies. Artif Organs 2003; 27:802-7. [PMID: 12940902 DOI: 10.1046/j.1525-1594.2003.07282.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recent clinical data indicate both ultrafiltration rate (Qf) and timing of treatment initiation in continuous renal replacement therapy (CRRT) and therapy frequency in intermittent hemodialysis (HD) influence survival in critically ill patients with acute renal failure (ARF). In this study, kinetic modeling is used to compare effective dose delivery by three acute dialysis therapies: continuous venovenous hemofiltration (CVVH), daily HD, and sustained low-efficiency dialysis (SLED). A modified equivalent renal clearance (EKR) approach to account for the initial unsteady-state stage during dialysis is employed. Effective small solute clearance in CVVH is found to be 8% and 60% higher than in SLED and daily HD, respectively. Differences are more pronounced for middle and large solute categories, and EKR in CVVH is approximately 2-fold and 4-fold greater than the corresponding values in daily HD and SLED, respectively. The superior middle and large solute removal for CVVH is due to the powerful combination of convection and continuous operation. In CVVH, a decrease in the initial BUN from 150 to 50 mg/dL is predicted to decrease TAC and, therefore, increase EKR by approximately 35%. After clinical validation, the quantification method presented in this article could be a useful tool to assist in the dialytic management of critically ill ARF patients.
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Affiliation(s)
- Zhijie Liao
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY, USA
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Wolfson M, Piraino B, Hamburger RJ, Morton AR. A randomized controlled trial to evaluate the efficacy and safety of icodextrin in peritoneal dialysis. Am J Kidney Dis 2002; 40:1055-65. [PMID: 12407652 DOI: 10.1053/ajkd.2002.36344] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND This article presents the results of two randomized, double-blind, controlled studies conducted to compare the efficacy and long-term safety of icodextrin and 2.5% dextrose for the once-daily long dwell in continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD). METHODS Both studies were active-control comparisons of 7.5% icodextrin and 2.5% dextrose for the once-daily long dwell. The efficacy study was a 4-week evaluation of net ultrafiltration and peritoneal clearances of creatinine and urea nitrogen in 175 CAPD patients. The 52-week study in CAPD and APD patients examined the long-term safety of icodextrin and longer term effects, such as body weight and quality of life. RESULTS Mean net ultrafiltration (587.2 versus 346.2 mL, P < 0.001) and clearances of urea nitrogen (4.5 versus 4.1 mL/min, P < 0.001) and creatinine (4.0 versus 3.5 mL/min, P < 0.001) were increased significantly with icodextrin. Patients receiving icodextrin had no increase in weight after 52 weeks, in contrast to a weight gain of almost 2 kg in the dextrose group (P < 0.05). There were significantly fewer patients reporting edema in the icodextrin group compared with the dextrose group (6.3% versus 17.9%, P < 0.01). There were no statistically significant differences between groups for the incidence and severity of adverse events. There were small decreases in sodium and chloride and increases in alkaline phosphatase with icodextrin. CONCLUSION Icodextrin provides patients with greater fluid removal and small solute clearance, no weight gain over 52 weeks, and a decreased risk of edema.
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Affiliation(s)
- Marsha Wolfson
- Renal Division, Baxter Healthcare Corporation, McGaw Park, IL 60085-6730, USA.
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40
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Teixidó–Planas J. Peritoneal Function and Adequacy Calculations: Current Programs versus PD Adequest 2.0. Perit Dial Int 2002. [DOI: 10.1177/089686080202200314] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objective Our current programs (CPs) were compared to PD Adequest 2.0 (PD-A) for calculations of peritoneal membrane transport and dialysis adequacy. Design Thirty peritoneal equilibration tests (PETs) and 24-hour balances (24hBs) were conducted and calculated using our CPs and PD-A. Patients and Methods Thirty hospital-controlled peritoneal dialysis (PD) patients were studied. The inclusion of correction factors (for glucose or plasmatic water) and of residual volume, and the use of 3 or 6 peritoneal samples were analyzed to discover the differences between programs. The main outcome measures were peritoneal permeability and adequacy parameters, evaluated by Student t-test (mean and paired comparisons) and linear regression for correlation. Results No significant differences were found in D/P values for small solutes. At the first step, mass transfer area coefficient (MTAC) urea and MTAC creatinine were significantly higher in DP-A than in CP, but MTAC glucose did not differ. The causes of differences were: ( 1 ) inclusion of a correction factor for aqueous plasmatic concentration of small solutes in CP; ( 2 ) lack of inclusion of residual volume in peritoneal volumes in CP; and ( 3 ) use of 6 peritoneal samples in CP versus 3 in PD-A. At the second step, when the input data were made equivalent for both programs, the differences disappeared for MTAC urea, creatinine, and glucose (mean comparison), but creatinine and glucose remained different by paired comparison. Similar results were obtained when a correction for plasmatic aqueous concentration was applied to the data in both programs [MTAC urea: 22.60 ± 4.27 mL/min (CP) vs 22.43 ± 4.61 mL/min (PD-A), nonsignificant, r = 0.97; MTAC creatinine: 9.76 ± 3.83 mL/min (CP) vs 10.61 ± 3.07 mL/min (PD-A), nonsignificant, r = 0.98; MTAC glucose: 13.30 ± 3.12 mL/min (CP) vs 11.87 ± 3.41 mL/min (PD-A), nonsignificant, r = 0.92]. Creatinine and glucose were different by paired t-test. No significant differences were found in Kt/V and urea generation rate. Weekly creatinine clearance [WCCr: 70.71±16.71 L (CP) versus 79.33±18.73 L (PD-A), p < 0.001] and creatinine generation rate [CrGR: 0.56 ± 0.18 mg/min (CP) versus 0.61±0.19 mg/min (PD-A), p < 0.001) were significantly higher in PD-A than in CP owing to the lack of creatinine correction according to glucose concentration in the PD-A adequacy program. Finally, normalized protein nitrogen appearance according to Bergström [1.09 ± 0.20 g/kg/d (CP) versus 1.03 ± 0.21 g/kg/d (PD-A), p = 0.01] was different owing to the different algorithms and normalization method: standardized body weight in CP and actual body weight in PD-A. Conclusions Provided that equivalent data are used, PD-A and CP yield similar results. The PD-A program needs external correction of data input: ( 1 ) for plasmatic water concentration in MTAC calculations, and ( 2 ) for peritoneal glucose interference with creatinine analysis (Jaffé method) in WCCr and CrGR calculations; otherwise, it may give falsely optimistic results.
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Affiliation(s)
- Josep Teixidó–Planas
- Department of Nephrology, Hospital Universitari Germans Trias i Pujol, Badalona (Barcelona), Spain
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41
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Warady BA. Should the Doqi Adequacy Guidelines be used to Standardize Peritoneal Dialysis in Children? Perit Dial Int 2001. [DOI: 10.1177/089686080102103s29] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Bradley A. Warady
- University of Missouri, School of Medicine, and The Children's Mercy Hospital, Kansas City, Missouri, U.S.A
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42
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Abstract
Automated peritoneal dialysis (APD) is the fastest growing technique of peritoneal dialysis. However, recently APD has displayed some limitations imposed by the characteristics of the technique and by the characteristics of the peritoneal membrane of some patients. In general, the advent of a new technique such as continuous flow peritoneal dialysis (CFPD) should be seen as a benefit for several patients based on different considerations: CFPD is a high-efficiency technique which could overcome some of the limitations imposed by other techniques in terms of adequacy targets and performance. CFPD may become a useful tool to keep patients on PD who would otherwise be transferred to hemodialysis. CFPD may present advantages in terms of biocompatibility and also in terms of the possible modulation of the peritoneal solution to patient needs. Recent developments in technology seem to have made CFPD easily feasible and well tolerated. A new era of PD is probably beginning and CFPD will definitely represent one of the key issues in the future of PD.
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Affiliation(s)
- C Ronco
- Department of Nephrology, St. Bortolo Hospital, Vicenza, Italy.
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Abstract
The National Kidney Foundation-Dialysis Outcomes Quality Initiatives guidelines have standardized many aspects of treating end-stage renal disease patients with peritoneal dialysis in an attempt to improve overall patient outcome. While recommending certain total solute clearance goals, the guidelines have also pointed out deficiencies in our knowledge base and precipitated many controversies. Some of these controversies have been resolved while others may have been interpreted wrongly, unnecessarily resulting in transfer of patients from peritoneal dialysis to hemodialysis due to "failure to meet adequacy targets" even when doing well clinically. This report reviews the rationale for the original guidelines and their subsequent modification. It also outlines a rational approach toward prescription modification based on peritoneal physiology. Specific solute clearance target goals discussed are the modifications for continuous ambulatory peritoneal dialysis (CAPD) and cycler peritoneal dialysis (CCPD), and a review of what solute clearance targets subsequent guidelines from other countries have used. Some examples are as follows: new guidelines suggest that solute clearance goals for creatine clearance should differ for low and low-average transporters than for high and high-average transporters (weekly clearance of 50 and 60 1/1.73 m(2), respectively) while Kt/V targets remain unchanged. Also discussed is the rationale for having the same target for patients on CCPD with a mid-day exchange as those for patients on CAPD. We are also reminded that solute clearance is only one aspect of "adequate" dialysis-blood pressure and volume control are equally important, and ways to maintain euvolemia and blood pressure control are discussed in the context of prescription management.
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Affiliation(s)
- J M Burkart
- Department of Internal Medicine/Nephrology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
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45
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Rippe B, Levin L. Computer simulations of ultrafiltration profiles for an icodextrin-based peritoneal fluid in CAPD. Kidney Int 2000; 57:2546-56. [PMID: 10844624 DOI: 10.1046/j.1523-1755.2000.00114.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The three-pore model of peritoneal transport has the ability to predict ultrafiltration (UF) profiles rather accurately, even when high molecular weight (MW) solutes are employed as osmotic agents in continuous ambulatory peritoneal dialysis (CAPD). In the present simulations, we wanted to assess, for various theoretical perturbations, the UF properties of a peritoneal dialysis (PD) solution with an osmotic agent having an average MW of 20 kD and a "number average MW" of 6.2 kD, which is similar to that of icodextrin (ICO). METHODS For a PD solution containing a completely monodispersed 20 kD MW osmotic agent, the degree of UF modeled is much higher than that reported for ICO. Hence, to model the behavior of ICO, we subdivided the ICO molecules into eight or more different MW size fractions. For simulations using six or eight subfractions, we obtained an excellent fit of simulated to reported UF data. More dispersed solutions produced UF profiles similar to that with eight fractions. RESULTS A 2.05 L 7.5% ICO PD solution, despite being slightly hypotonic, yielded a UF volume of nearly 600 mL in 12 hours, modeled for patients not previously exposed for ICO. After nine hours, the UF volume exceeded that produced by 3.86% glucose. The UF rate and volumes increased in proportion to (1) the ICO concentration, (2) the peritoneal surface area, and (3) the peritoneal UF coefficient, but was almost insensitive to increases in the instilled fluid volume. Simulated for patients previously exposed to ICO, having steady-state plasma concentrations of ICO degradation products, the predicted UF volume at 12 hours was reduced to approximately 400 mL. CONCLUSION Employing the three-pore model of peritoneal transport and taking into account the polydispersed nature of ICO, it was possible to accurately computer simulate the UF profiles of ICO in accordance with reported data. The simulations suggest an advantage of using ICO in patients with type I UF failure, where UF with a high-MW osmotic agent will exceed that seen in patients not showing UF failure who are on glucose-based PD solutions.
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Affiliation(s)
- B Rippe
- Department of Nephrology, University Hospital of Lund, Lund, Sweden
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46
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Hamada H, Sakiyama R, Yamashita AC, Okamoto M, Tojo KJ, Kumano K, Sakai T. Validation of a new analytical model for peritoneal transport model using rabbit in vivo experimental data. Nephrology (Carlton) 2000. [DOI: 10.1046/j.1440-1797.2000.00517.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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47
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Katsutani M, Yorioka N, Ito T, Naito T, Kanahara K, Oda H, Yamakido M. Evaluation of the PD Adequest Program in Japanese Patients on Peritoneal Dialysis. Int J Artif Organs 1999. [DOI: 10.1177/039139889902200903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To perform adequate peritoneal dialysis, it is necessary to individualize the dialysis regimen. PD Adequest is a software program based on the three-pore model that can be used to predict solute clearance and ultrafiltration volume during peritoneal dialysis. We evaluated the ability of this program to predict the solute clearance and ultrafiltration volume in Japanese patients on peritoneal dialysis. The weekly creatinine clearance and weekly urea Kt/V were determined in 45 patients. The PD Adequest was used to simulate their current dialysis regimens and the predicted values of these parameters were calculated. Strong positive correlations were obtained between the actual and predicted weekly creatinine clearance (r=0.993) and weekly urea Kt/V (r=0.991). In conclusion, this program is potentially useful for designing peritoneal dialysis regimens in Japanese patients, even though they have a smaller body mass than Canadians and Americans for whom it was designed.
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Affiliation(s)
- M. Katsutani
- Second Department of Internal Medicine, Hiroshima University School of Medicine, Hiroshima
| | - N. Yorioka
- Second Department of Internal Medicine, Hiroshima University School of Medicine, Hiroshima
| | - T. Ito
- Second Department of Internal Medicine, Hiroshima University School of Medicine, Hiroshima
| | - T. Naito
- Kure National Hospital, Hiroshima - Japan
| | | | - H. Oda
- Kure National Hospital, Hiroshima - Japan
| | - M. Yamakido
- Second Department of Internal Medicine, Hiroshima University School of Medicine, Hiroshima
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48
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Clark WR, Leypoldt JK, Henderson LW, Mueller BA, Scott MK, Vonesh EF. Quantifying the effect of changes in the hemodialysis prescription on effective solute removal with a mathematical model. J Am Soc Nephrol 1999; 10:601-9. [PMID: 10073611 DOI: 10.1681/asn.v103601] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
One potential benefit of chronic hemodialysis (HD) regimens of longer duration or greater frequency than typical three-times-weekly schedules is enhanced solute removal over a relatively wide molecular weight spectrum of uremic toxins. This study assesses the effect of variations in HD frequency (F: per week), duration (T: min per treatment), and blood/dialysate flow rates (QB/QD: ml/min) on steady-state concentration profiles of five surrogates: urea (U), creatinine (Cr), vancomycin (V), inulin (I), and beta2-microglobulin (beta2M). The regimens assessed for an anephric 70-kg patient were: A (standard): F = 3, T = 240, QB = 350, QD = 600; B (daily/short-time): F = 7, T = 100, QB = 350, QD = 600; C/D/E (low-flow/long-time): F = 3/5/7, T = 480, QB = 300, QD = 100. HD was simulated with a variable-volume double-pool model, which was solved by numerical integration (Runge-Kutta method). Endogenous generation rates (G) for U, Cr, and beta2M were 6.25, 1.0, and 0.17 mg/min, respectively; constant infusion rates for V and I of 0.2 and 0.3 mg/min, respectively, were used to simulate middle molecule (MM) G values. Intercompartment clearances of 600, 275, 125, 90, and 40 ml/min were used for U, Cr, V, I, and beta2M, respectively, For each solute/regimen combination, the equivalent renal clearance (EKR: ml/min) was calculated as a dimensionless value normalized to the regimen A EKR, which was 13.4, 10.8, 6.6, 3.7, and 4.8 ml/min for U, Cr, V, I, and beta2M, respectively. For regimens B, C, D, and E, respectively, these normalized EKR values were U: 1.04, 0.96, 1.58, and 2.22; Cr: 1.03, 1.08, 1.80, and 2.55; V: 1.06, 1.32, 2.21, and 3.12; I: 1.05, 1.54, 2.57, and 3.62; beta2M: 1.00, 1.27, 1.73, and 2.19. The extent of post-HD rebound (%) was highest for regimens A and B, ranging from 16% (urea) to 50% (inulin), and lowest for regimen E, ranging from 6% (urea) to 28% (beta2M). The following conclusions can be made: (1) Relative to a standard three-times-weekly HD regimen of approximately the same total (weekly) treatment duration, a daily/short-time regimen results in modest (3 to 6%) increases in effective small solute and MM removal. (2) Relative to a standard three-times-weekly HD regimen, a three-times-weekly low-flow/long-time regimen results in comparable effective small solute removal and progressive increases in MM and beta2M removal. A daily low-flow/long-time regimen substantially increases the effective removal of all solutes.
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Affiliation(s)
- W R Clark
- Renal Division, Baxter Healthcare Corporation, McGaw Park, Illinois 60085, USA.
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49
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Hamada H, Sakiyama R, Yamashita AC, Okamoto M, Tojo KJ. New Analytical Solution for Pyle-Popovich's Peritoneal Dialysis Model. JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 1999. [DOI: 10.1252/jcej.32.498] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Hiroyuki Hamada
- Department of Biochemical Engineering and Science, Kyushu Institute of Technology
| | - Ryoichi Sakiyama
- Department of Biochemical Engineering and Science, Kyushu Institute of Technology
| | - Akihiro C. Yamashita
- Department of Material Science and Ceramic Technology, Shonan Institute of Technology
| | - Masahiro Okamoto
- Department of Biochemical Engineering and Science, Kyushu Institute of Technology
| | - Kakuji J. Tojo
- Department of Biochemical Engineering and Science, Kyushu Institute of Technology
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50
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Brant JA, Hanlon GW, Denyer SP. Development of an in-vitro model to study the growth characteristics of Staphylococcus epidermidis in continuous ambulatory peritoneal dialysis. J Pharm Pharmacol 1998; 50:1195-203. [PMID: 9821670 DOI: 10.1111/j.2042-7158.1998.tb03334.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An in-vitro model of peritonitis in continuous ambulatory peritoneal dialysis (CAPD) has been developed which integrates the parameters of environmental gaseous tension, the changing biochemical profile of the dialysate, and the periodic challenge of fresh fluid. Dwell times of 4 h during the day and 10 h at night were used to reflect the in-vivo situation. Biochemical analysis of dialysate within the model showed that the profiles for creatinine, glucose and protein approximated those found in patients. Staphylococcus epidermidis growing in synthetic dialysis effluent or pooled dialysis fluid were seen to adapt rapidly to the environment after an initial lag phase; a tendency to aggregate together increased over the 50-h period of operation. In conclusion, the results presented here suggest that this in-vitro model creates an environment which is reflective of the in-vivo situation and therefore has potential for the study of peritonitis in CAPD.
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Affiliation(s)
- J A Brant
- Department of Pharmacy, University of Brighton, Moulsecoomb, East Sussex, UK
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