Dialysis Capacity Research Articles

Bad and good growth factors in the peritoneal cavity (Review Article)

Progressive peritoneal membrane fibrosis, and associated loss of ultrafiltration and dialysis capacity, is an increasingly limiting problem with time on peritoneal dialysis. The primary culprit is the composition of the peritoneal dialysate, although episodes of peritonitis can hasten the process. At a molecular level, there is increasing evidence that several growth factors play key roles in the development of peritoneal membrane fibrosis. Transforming growth factor (TGF)-beta is widely implicated in pathological fibrosis, and a considerable body of evidence favours a similar role in the peritoneal membrane. Connective tissue growth factor (CTGF), a downstream mediator of TGF-beta-induced fibrosis, has more recently been implicated in peritoneal membrane scarring. In contrast to the pleiotropic effects of TGF-beta, CTGF more specifically targets the fibrosis pathway, and so is an attractive candidate for inhibiting the damage to the membrane. Heparin-binding epidermal growth factor-like growth factor (HB-EGF) has also been found in the peritoneal cavity, but its effect on peritoneal mesothelial cells suggests that it has a positive role in guiding membrane repair and avoiding pathological fibrosis. In the future, it is hoped that changes in peritoneal dialysis technology will create a better balance between the bad and good effects of these growth factors, which in turn will lead to more successful long-term outcomes for this major renal replacement therapy.

Do interleukin-6, hyaluronan, soluble intercellular adhesion molecule-1 and cancer antigen 125 in dialysate predict changes in peritoneal function?

Diminishing ultrafiltration and dialysis adequacy may limit the long-term use of peritoneal dialysis (PD). Inflammation may play a role in changes in peritoneal function. This study was designed to evaluate alterations in peritoneal function and soluble factors in dialysate during a 1-year follow-up period. A personal dialysis capacity test was performed at the start of the study and after 6 and 12 months in 20 patients in order to determine dialysis adequacy and membrane characteristics. Dialysate was collected during the test days for analyses of interleukin-6 (IL-6), soluble intercellular adhesion molecule-1, hyaluronan and cancer antigen 125 (CA125). There were no significant changes in dialysis adequacy or membrane characteristics during the 1-year follow-up period. The appearance rate of IL-6 in dialysate increased significantly (419.8+/-63.3 at the start, 784.1+/-136.4 after 6 months and 1149.3+/-252.2 ng/24 h after 12 months; p=0.006) during follow-up. Furthermore, the appearance rate of CA125 increased throughout the study in patients using icodextrin, but decreased slightly in patients using only conventional dialysis solutions. There were no major changes in dialysis adequacy or membrane characteristics during the follow-up period, but increased IL-6 in dialysate may reflect peritoneal inflammation, which may lead to long-term alterations in the peritoneal membrane. Icodextrin may have a preventive effect on the longevity of the peritoneal membrane.

The effect of contraindications and patient preference on dialysis modality selection in ESRD patients in The Netherlands

Background: Patients with end-stage renal disease (ESRD) who are about to start long-term dialysis therapy are faced with the question of modality choice. The aim of the current study is to determine the influence of different factors on long-term dialysis modality choice. Methods: As part of a large Dutch prospective multicenter study, the Netherlands Cooperative Study on the Adequacy of Dialysis, we consecutively included all new patients with ESRD. Nephrologists indicated the most important reason for the modality selection. Results: Of 1,347 included patients, 36% (n = 483) had a contraindication to either peritoneal dialysis (PD) or hemodialysis (HD) therapy. Eighty percent (n = 386) of all contraindications were directed to PD therapy. The most frequently mentioned contraindication was a social one; ie, the expected incapability of patients to perform PD exchanges themselves. Patients with contraindications were older, had more comorbidity, and lived alone more often compared with patients without contraindications. In patients without contraindications (64%), modality choice was based on patient preference. Older age increased the odds of choosing HD, whereas receipt of predialysis care was associated with a lower preference for HD. Conclusion: Older age was associated with more contraindications to PD therapy and stronger patient preference for HD therapy. An elderly patient therefore was more likely to start with HD therapy. Results from the current study suggest that an increase in provision of predialysis care, in combination with a reduction in social contraindications to PD therapy, may be associated with an increase in likelihood of starting with PD therapy. In a time of an aging population, increasing demand on dialysis capacity, and limited amount of financial supplies, we may reconsider current strategies to provide future patients with ESRD the possibility to start with the dialysis modality they prefer.

In vitro and in vivo models for peritonitis demonstrate unchanged neutrophil migration after exposure to dialysis fluids.

Recurrent infections in peritoneal dialysis (PD) patients may alter the abdominal wall resulting in an impairment of its dialysis capacity. In this study we investigated both in vitro and in vivo the effects of mesothelial exposure to dialysis fluids on the migration of neutrophils and their capacity to clear a bacterial infection. First, we evaluated neutrophil migration in an in vitro transwell model for the peritoneal membrane with monolayers of primary human mesothelial cells (MC) on the lower side and primary human endothelial cells (EC) on top of the same transwell membrane, upon exposure of MC to PD fluid (PDF)-derived components. In addition to this in vitro model, we combined chronic peritoneal exposure to PDF with a peritoneal infection model in the rat. We investigated the kinetics of the chemokine response, neutrophil recruitment and bacterial clearance. Known chemoattractants, such as fMLP and IL-8, strongly increased neutrophil migration across both cell layers in the in vitro model of the peritoneal membrane. Pre-incubation of the MC layer for 48 h with 55 mM glucose, a combination of two glucose degradation products, methylglyoxal and 3-deoxyglucosone, or conventional dialysis fluid (1:4 dilution), however, did not change the IL-8-induced migration of neutrophils. In concert with this finding we demonstrated an unchanged MC expression of ICAM-1 and VCAM-1 after these pre-treatments. Unexpectedly, chronic i.p. exposure to conventional PDF or a recently developed lactate/bicarbonate-buffered PDF in a rat peritoneal exposure model strongly hampered the chemokine response upon bacterial challenge. Nevertheless, neutrophil recruitment and bacterial clearance were effective and did not differ from rats not pre-exposed to PDF. We conclude that exposure of MC to PDF does not hamper the recruitment of functional neutrophils upon challenge.

Hypoproteinemia in Patients with Diabetes Undergoing Continuous Ambulatory Peritoneal Dialysis is Attributable to High Permeability of Peritoneal Membrane

The present study used the newly developed personal dialysis capacity (PDC) peritoneal function test to investigate differences in individual peritoneal membrane transport function and nutritional status in non diabetic (non DM) and diabetic (DM) patients on continuous ambulatory peritoneal dialysis (CAPD). To clarify the differences in peritoneal function that determine plasma protein levels, we carried out PDC tests in non DM and DM patients. Between May 1995 and May 1999, in multicenter study in Japan, we carried out 232 PDC tests on 232 non DM patients and 47 PDC tests on 47 DM patients who had been on CAPD for 1 - 210 months. Plasma levels of total protein and albumin in DM patients were significantly lower than those in non DM patients (total protein: 6.5 +/- 0.1 g/dL non DM vs. 5.9 +/- 0.1 g/dL DM, p < 0.0001; albumin: 3.5 +/- 0.1 g/dL non DM vs. 2.9 +/- 0.1 g/dL DM, p < 0.0001). The mean membrane area in the DM group was significantly larger than that in the non DM group (21 943 +/- 608 cm/1.73 m(2) non DM vs. 26 304 +/- 1699 cm/1.73 m(2) DM, p = 0.0076). The mean plasma loss through the large pores in the DM group was significantly greater than that in the non DM group (0.095 +/- 0.004 mL/min/1.73 m(2) non DM vs. 0.119 +/- 0.008 mL/min/1.73 m(2) DM, p = 0.0113). Protein loss into dialysate in DM patients was significantly greater than that in non DM patients. We observed a significant correlation between total protein or albumin and plasma loss from dialysis solution in non DM and DM patients on CAPD. The study demonstrated that peritoneal function, including peritoneal membrane transport and peritoneal permeability to protein was significantly higher in DM patients than in non DM patients. Hypoproteinemia in DM patients might be associated with high permeability of peritoneal membrane in CAPD.

Effect of diabetes on peritoneal function assessed by personal dialysis capacity test in patients undergoing CAPD

Background: We evaluated differences in individual peritoneal membrane transport function and nutritional status in patients with diabetes mellitus (DM) and nondiabetic (non-DM) patients on continuous ambulatory peritoneal dialysis (CAPD). Methods: We used a newly developed peritoneal function test, personal dialysis capacity, in 88 patients (44 DM and 44 non-DM) on CAPD for 1 to 210 months. Sex, age, past history of peritonitis, and duration of CAPD were matched in DM and non-DM patients. Results: Serum albumin (mean ± SEM) was lower in DM compared with non-DM patients: 3.0 ± 0.1 g/dL (30 ± 1 g/L) versus 3.5 ± 0.1 g/dL (35 ± 1 g/L), P < 0.001. Peritoneal area and dialysis protein loss were greater in DM versus non-DM patients. In multiple linear regression analysis, the only independent predictor of serum albumin in patients with DM was dialysis protein loss. In contrast, age, past history of peritonitis, duration of CAPD, caloric intake, protein nitrogen appearance and protein catabolic rate, and residual renal function did not correlate with serum albumin in DM patients. In non-DM patients, age, duration of CAPD, and past history of peritonitis, but not dialysis protein loss, were independent predictors of serum albumin. There was a significant correlation in DM patients, but not in non-DM CAPD patients, between dialysis protein loss and urinary excretion of protein (r = 0.866, P = 0.0005). Conclusion: In this multicenter study, peritoneal membrane transport and peritoneal protein permeability were significantly higher in DM than in non-DM patients. Hypoproteinemia in DM patients is attributable to the high permeability of the peritoneal membrane undergoing CAPD. Am J Kidney Dis 40:1045-1054. © 2002 by the National Kidney Foundation, Inc.

Nutritional status in peritoneal dialysis: studies in body composition, lipoprotein metabolism and peritoneal function.

This thesis is based on clinical studies including virtually all patients treated with peritoneal dialysis in Gothenburg during the 1990s. The patients had a fundamentally altered body composition compared to healthy subjects, characterised by a reduction in body cell mass and body fat already at start of dialysis. During PD treatment. a further decrease in body cell mass was observed. Energy stores tended to normalise during the first years of treatment and remained constant thereafter, or declined subsequently. Extracellular water, calculated from the four-compartment model, was increased when patients started PD treatment and increased further, in parallel to the reduction in body cell mass. These alterations were seen in combination with a normal. or slightly reduced, body weight. Standard methods of assessing nutritional status may therefore not be valid in the dialysis population. Prediction equations to estimate total body water, used in measurements of dialysis adequacy, give erroneous results in PD patients, as shown in a study on our PD population. This may have important clinical consequences, especially in wasted patients. Reduced muscle mass is a marker of protein-energy malnutrition, and therefore simple and reliable methods to measure muscle mass are warranted. When lean body mass was calculated from creatinine generation rate and compared to lean body mass estimated from measurements of total body potassium. the agreement between the two methods was low. Furthermore, when repeated measurements of creatinine generation rate were performed, the variation coefficient was unacceptably high. Thus. creatinine generation rate cannot be recommended as a method to evaluate somatic protein status in PD patients. The lipoprotein metabolic derangements are pronounced in PD patients. in which a further increase in cholesterol and cholesterol-rich apoB-containing lipoproteins are added to the already pre-existing renal dyslipidemia. characterised by increased concentration of triglycerides and triglyceride-rich complex lipoproteins. There are indications that dialytic variables may influence this development. When peritoneal function was assessed by the Peritoneal Dialysis Capacity test at start of dialysis, it was observed that peritoneal function reflected patient characteristics and co-morbidity. Patients with systemic disease had enhanced diffusion capacity compared to patients with primary renal disorders. Furthermore, in patients with more severe co-morbidity. peritoneal protein losses were increased. Finally, elderly patients had ultrafiltration conditions that were different from those of younger patients. Peritoneal function remained essentially stable during medium-long term follow up. Body composition features in dialysis patients are similar to those seen in severe disease in general. Thus, it is difficult to separate the effects of malnutrition from the effects of the underlying disease. Specific standards for nutritional status adapted for patients with renal failure are required.

Evaluation of DOQI guidelines: early start of dialysis treatment is not associated with better health-related quality of life.

The National Kidney Foundation-Dialysis Outcomes Quality Initiative (DOQI) guideline, which is largely opinion based, promotes an earlier initiation of dialysis treatment than usual. Implementation of this guideline would require an expansion of dialysis capacity, leading to a considerable increase in costs. Such an expansion can only be justified by an improvement in patient outcome. We studied the effect of late versus timely initiation of dialysis treatment on the course of health-related quality of life (HRQOL) in new dialysis patients. As part of a large Dutch prospective multicenter study (Netherlands Cooperative Study on the Adequacy of Dialysis-2), we consecutively included all new patients with end-stage renal disease for whom residual renal function could be obtained 0 to 4 weeks before the start of dialysis therapy. HRQOL was assessed by means of the Kidney Disease and Quality of Life Short Form at regular intervals during the first year of chronic dialysis treatment. According to the DOQI guideline, 90 of the 237 included patients (38%) started dialysis treatment too late. All patients showed marked improvement in HRQOL during the first 6 months after the start of dialysis treatment. Compared with patients who started dialysis treatment too late, patients who started in time had significantly higher HRQOL for a number of dimensions immediately after the start of treatment. After 12 months of dialysis treatment, these differences had disappeared. An evidence-based recommendation on an early start of dialysis treatment is still difficult to give. In the short term, an earlier start resulted in better HRQOL. However, within 1 year, this advantage had disappeared. It is unclear whether this short-term benefit outweighs the extra restrictions associated with earlier initiation of dialysis therapy. Consequently, only the patient, in consultation with the nephrologist, is able to weigh both sides.

Cytokines and other soluble factors in dialysate -- indicators of altered peritoneal function?

The bioincompatibility of dialysis solutions and recurrent episodes of peritonitis may alter peritoneal function. Cytokines and growth factors may play a role in inflammatory and fibrotic processes. We therefore investigated whether there is a correlation between peritoneal function and excretion of cytokines and other soluble factors in dialysate. A personal dialysis capacity test was performed in 40 stable peritoneal dialysis patients. Tumour necrosis factor-alpha, interleukin-6 (IL-6), hyaluronan, soluble intercellular cell adhesion molecule-1 and transforming growth factor-beta1 were analysed from overnight and 24-h dialysates during the test. We found little evidence for a direct correlation between cytokines and other soluble factors in dialysate and dialysis adequacy. There was, however, a strong correlation between the measured soluble factors and characteristics of the peritoneal membrane. Furthermore, IL-6 correlated with the number of previous episodes of peritonitis. Soluble factors in dialysate may indicate ongoing inflammatory processes in the peritoneal membrane, which may gradually lead to alterations in peritoneal function.

Optimization of Peritoneal Dialysis Prescription Using Computer Models of Peritoneal Transport

Computer models are valuable clinical tools in the effort to improve quality of life for dialysis patients. At present, two software programs have been validated clinically in adult and pediatric populations. They are the Personal Dialysis Capacity (PDC: Gambro Lundia AB, Lund, Sweden) and PD Adequest (Baxter Healthcare Corporation, Deerfield, IL, U.S.A.). Both programs seem to give accurate predictions of small-solute clearance, but the PDC seems to be superior in predicting ultrafiltration volumes. Indeed, the software programs have several important differences that affect their accuracy and, hence, their clinical value. The PDC software introduces the concepts of capillary physiology to the field of peritoneal dialysis. It gives a functional description of the peritoneal membrane of the individual patient. Recently, its "new" area parameter (A0/delta x) was shown to be superior to the peritoneal equilibration test (PET) in predicting transperitoneal exchange.

Monitoring of Long-Term Peritoneal Membrane Function

Peritoneal membrane function influences dialysis prescription and clinical outcome and may change with time on treatment. Increasingly sophisticated tools, ranging from the peritoneal equilibration test (PET) to the standard permeability analysis (SPA) and personal dialysis capacity (PDC) test, are available to the clinician and clinical researcher. These tests allow assessment of a number of aspects of membrane function, including solute transport rates, ultrafiltration capacity, effective reabsorption, transcellular water transport, and permeability to macromolecules. In considering which tests are of greatest value in monitoring long-term membrane function, two criteria were set: those that result in clinically relevant interpatient differences in achieved ultrafiltration or solute clearances, and those that change with time in treatment. Clinical validation studies of the PET, SPA, and PDC tests. Studies reporting membrane function using these methods in either long-term (5 years) peritoneal dialysis patients or longitudinal observations (> 2 years). Directly from published data. Additional, previously unpublished analysis of data from the Stoke PD Study. Solute transport is the most important parameter. In addition to predicting patient and technique survival at baseline, there is strong evidence that it can increase with time on treatment. Whereas patients with initially high solute transport drop out early from treatment, those with low transport remain longer on treatment, although, over 5 years, a proportion develop increasing transport rates. Ultrafiltration capacity, while being a composite measure of membrane function, is a useful guide for the clinician. Using the PET (2.27% glucose), a net ultrafiltration capacity of < 200 mL is associated with a 50% chance of achieving less than 1 L daily ultrafiltration at the expense of 1.8 hypertonic (3.86%) exchanges in anuric patients. Using a SPA (3.86% glucose), a net ultrafiltration capacity of < 400 mL indicates ultrafiltration failure. While there is circumstantial evidence that, with time on peritoneal dialysis, loss of transcellular water transport might contribute to ultrafiltration failure, none of the current tests is able to demonstrate this unequivocally. Of the other membrane parameters, evidence that interpatient differences are clinically relevant (permeability to macromolecules), or that they change significantly with time on treatment (effective reabsorption), is lacking. A strong case can be made for the regular assessment by clinicians of solute transport and ultrafiltration capacity, a task made simple to achieve using any of the three tools available.

Long-term clinical effects of a peritoneal dialysis fluid with less glucose degradation products

Glucose degradation products (GDPs) are cytotoxic in vitro and potentially toxic in vivo during peritoneal dialysis (PD). We are presenting the results of a two-year randomized clinical trial of a new PD fluid, produced in a two-compartment bag and designed to minimize heat-induced glucose degradation while producing a near neutral pH. The effects of the new fluid over two years of treatment on membrane transport characteristics, ultrafiltration (UF) capacity, and effluent markers of peritoneal membrane integrity were investigated and compared with those obtained during treatment with a standard solution. A two-group parallel design with 80 continuous ambulatory peritoneal dialysis patients was used. The patients were randomly assigned to either the new fluid (N = 40) or to a conventional one (N = 40), and were stratified with respect to age, diabetes, and time on PD. Peritoneal transport characteristics were assessed by the Personal Dialysis Capacity (PDCtrade mark) test at 1, 6, 12, 18, and 24 months after inclusion and by weighing the overnight bag daily. Infusion pain and handling were evaluated using a questionnaire. Peritoneal mesothelial and interstitial integrity were evaluated by analyzing overnight effluent dialysate concentrations of CA 125, hyaluronan (HA), procollagen-1-C-terminal peptide (PICP), and procollagen-3-N-terminal peptide (PIIINP) at 1, 6, 12, 18, and 24 months. The handling of the new two-compartment bag was considered easy, and there were no indications of increased discomfort with the new system. Furthermore, no changes in peritoneal fluid or solute transport characteristics were observed during the study period for either fluid, and neither were there any differences with regard to peritonitis incidence. However, significantly higher dialysate CA 125 (73 +/- 41 vs. 25 +/- 18 U/mL), PICP (387 +/- 163 vs. 244 +/- 81 ng/mL), and PIIINP (50 +/- 24 vs. 29 +/- 13 ng/mL) and significantly lower concentrations of HA (395 +/- 185 vs. 530 +/- 298 ng/mL) were observed in the overnight effluent during treatment with the new fluid. We conclude that the new fluid with a higher pH and less GDPs is safe and easy to use and has no negative effects on either the frequency of peritonitis or peritoneal transport characteristics as compared with conventional ones. Our results indicate that the new solution causes less mesothelial and interstitial damage than conventional ones; that is, it may be considered more biocompatible than a number of conventional PD solutions currently in use.

Dyslipidemia in Peritoneal Dialysis — Relation to Dialytic Variables

To investigate whether the specific lipoprotein (LP) abnormalities of peritoneal dialysis (PD) are associated with functional variables of this mode of dialysis. A survey of the LP profile in relation to peritoneal dialysis capacity (PDC) variables. The LP profile was compared to that of a group of age- and sex-matched controls. The Peritoneal Dialysis Unit at Sahlgrenska University Hospital in Gothenburg, Sweden. Twenty-two nondiabetic PD patients (5 women, 17 men) who had been on PD for at least 6 months. The LP profile included plasma lipids, apolipoproteins (Apo), and individual ApoA- and ApoB-containing LP. The PDC measurement determined peritoneal glucose uptake, protein losses, effective peritoneal surface area, and total weekly creatinine clearance. The patients had been on PD for 6 to 48 months (mean 15.3 months) and had a total weekly creatinine clearance of 69.7+/-13.3 L/1.73 m2 body surface area, an average peritoneal glucose uptake corresponding to 446+/-162 kcal/24 hour, and a protein loss of 8.1+/-2.5 g/24 hr. The patients had significantly higher total cholesterol (7.1 mmol/L),VLDL-cholesterol (1.0 mmol/L), LDL-cholesterol (4.7 mmol/L), and triglyceride levels (2.5 mmol/L); whereas the HDL-cholesterol level (1.2 mmol/L) was significantly lower than in controls. The PD patients had increased levels of ApoB-containing LPs, both of the cholesterol-rich LP-B and of the triglyceride-rich LP-B complex, reflected in higher plasma concentrations of ApoB, ApoC-III, and ApoE. Furthermore, they had significantly lower levels of LP-A-I:A-II, as well as of ApoA-I and ApoA-II. The LP-A-I:A-II and ApoA-II levels correlated inversely with the duration of PD treatment (r = 0.54, p < 0.01 and r = 0.52, p < 0.05, respectively). The ApoA-II level was inversely correlated with the peritoneal surface area (r = 0.53, p < 0.05). There were no other correlations between LP variables and PDC variables, nor did any of the LP variables correlate with peritoneal glucose uptake or protein losses. The proatherogenic lipoprotein profile of patients on PD is characterized by increased concentrations of cholesterol-rich and triglyceride-rich ApoB-containing LPs. While the duration of treatment appears to have some influence on the development of this type of dyslipidemia, the pathophysiological links to the dialysis mode must be further explored.

Estimation of peritoneal mass transport by three-pore model in children

Computerized modeling is increasingly used to optimize the efficacy of peritoneal dialysis (PD). The Personal Dialysis Capacity (PDC) test is a new tool to model PD efficacy based on the three-pore model of peritoneal mass transport. We sought to evaluate (i) whether the PDC test is applicable to children on chronic PD, and (ii) whether the physiological mass transport coefficients defined in the three pore model are dependent on age or body size in childhood. A validation study was performed in 32 pediatric chronic PD patients. Twenty tests were performed using a standard CAPD regimen, and 22 tests using a simplified automated PD (APD) protocol. Test accuracy and precision were evaluated by comparison of predicted with measured 24-hour dialysate clearances of urea, creatinine, beta2-microglobulin and albumin and ultrafiltration rates. Long-term reproducibility was assessed in 16 patients by repeated clearance studies after a median time interval of 10 weeks. While daily clearances of urea and creatinine were predicted with good precision and accuracy with both test protocols (concordance correlation coefficients 0.90 to 0.98, mean difference predicted-calculated -0.6 to +0.6 ml/min/1.73 m2), ultrafiltration rates were predicted more closely by the APD (r = 0.97) than by the CAPD test (0.80). Middle and large molecule clearances were predicted less precisely in both test settings (r = 0.48 to 0.83). Re-test reproducibility was slightly lower than the predictive precision observed in the original test (r = 0.80 to 0.91). The calculated total peritoneal pore area increased in absolute terms, decreased with body size when standardized to weight, and was independent of body size when normalized to body surface area. The body size-normalized fluid reabsorption rate was slightly increased in young infants compared to older children or adults. The PDC test permits to model peritoneal solute and water transport with remarkable precision in children of all age groups. While the peritoneal pore area is a linear function of body surface area, fluid reabsorption appears to be slightly increased in young infants.

How to evaluate and optimize peritoneal dialysis treatment.

ambulatory peritoneal dialysis (CAPD) but has untilnow been most cumbersome for patients treated withWe are constantly reminded of our shortcomings and automatic PD (APD), where the drain volumes mayinability to cure the increasing number of patients with be 15–30 l. Note that the estimate of clearance for PDend-stage renal disease. Indeed, we can oVer a variety is based on the removed mass and therefore independ-of dialysis modalities; also kidney transplantation ent of theoretical compartment models [8,9]. Thus, itis available. However, despite numerous technical is quite easy to assess the dialysis dose, at least foradvances and improvements, these patients have an patients on CAPD. Some computer programs utilizeincreased risk of complications, co-morbidity and pre- kinetic modelling to estimate and predict the eVects ofmature death. One problem is that only 5–10% of dialysis (e.g. [10,11]).normal renal function can be achieved with dialysis. In 1991, it was shown that 24 h drain volumeThis is true for both haemodialysis (HD) and periton- collections could be used to get a detailed descriptioneal dialysis (PD). At present, it is recommended that of the peritoneal dialysis capacity (PDC@) for indi-dialysis should give at least 6 ml/min/1.73 m2of clear- vidual patients [11,12]. The analysis is based on theance for a solute such as creatinine (or weekly Kt/V three-pore model [13,14] which currently seems to befor urea >1.9) for a patient on PD [1]. It is therefore the best description of the transcapillary passage ofof pivotal importance to obtain objective measure- fluid and solutes in the peritoneum as well as in mostments of dialysis eYcacy. Naturally, this is even more other organs [15]. The collection of drain fluid istrue for PD than for HD since the exchange occurs performed by the patient during a more or less normalacross a biological membrane with unknown, dynamic day on CAPD. The results are highly reproducible andand highly individual properties. By knowing the prop- agree well with the measured concentrations and drainerties of the peritoneal membrane, or by measuring volumes [11]. However, for patients treated with APD,clearance, it is possible to prescribe an ‘adequate’ it previously was necessary to switch to CAPD todialysis dose. perform the PDC test, which could be inconvenientIn PD, the additional challenge is that the patient for some patients, particularly for children.must be motivated to follow the given prescription. The aims of the present study were therefore: (i) toThis is illustrated by the fact that some studies have develop a technique to ensure reliable measurementsreported a low compliance rate (75–80%) for patients of the clearance during APD; and (ii) to use suchtreated with PD [2,3], a value that probably can be measurements for estimates of the PDC.questioned since it is based on creatinine kinetics [4,5].Nevertheless, it seems safe to conclude that few patients

Clinical application of the Personal Dialysis Capacity (PDC) test: Serial analysis of peritoneal function in CAPD patients

Peritoneal damage has been reported since the beginning of CAPD therapy. To clarify the change of peritoneal function in CAPD patients, we used the Personal Dialysis Capacity (PDC) test in 22 patients with 49 serial studies and 14 patients with single studies. The data were expressed at the condition of 2.5% (2.27 g/dl of glucose), four times at 2,000 ml/day. In the mass analysis, the urea generation rate, creatinine generation rate, PNA/PCR, and water removal via the peritoneum (PD) were kept at the same level for almost eight years, and then gradually decreased. Urine volume and residual renal creatinine clearance (CCr) became zero at six years. On the other hand, PD CCr increased gradually with the time course of CAPD, and therefore the total CCr remained at the level of 6.0 ml/min even after six years. Weekly urea KT/V decreased gradually from almost 2.800 to 2.000. The protein loss remained approximately 7.0 g/day for the initial five years, then became 6.0 g/day, except in five patients who showed levels above 10.0 g/day on the first test of PDC. Weekly urea KT/V was correlated with residual renal CCr (P < 0.005), and significantly correlated with total CCr (weekly urea KT/V = -0.2798 + 0.3720 x total CCr; r = 0.915, P < 0.001). In the serial analysis, when the first and the last tests were compared, the urea generation rate increased significantly (mean +/- SD, 2.800 +/- 3.204 vs. 3.882 +/- 3.382; P < 0.0001); however, water removal via PD (1364 +/- 887 vs. 813 +/- 609; P = 0.021), total ultrafiltration (1762 +/- 841 vs. 1124 +/- 843; P = 0.042), and weekly urea KT/V (2.285 +/- 0.486 vs. 2.112 +/- 0.512; P = 0.026) decreased significantly. The delta water removal via PD/ duration became negative (-10.03 +/- 6.59 ml/week) in all 7 patients after more than four years, however, it was positive (+14.40 +/- 7.84 ml/week) in 6 of 10 patients after less than one year. These results suggest that water removal via PD increases within one year, then decreases after four years. The PDC test is useful to evaluate the change of peritoneal function in mass and serial analyses.

Capd in Patients with Autosomal Dominant Polycystic Kidney Disease

To investigate whether there are specific complications to continuous ambulatory peritoneal dialysis (CAPD) in patients with autosomal dominant polycystic kidney disease (ADPKD) due to defects in various wall structures--causing hernia and diverticulitis--and to enlarged kidneys. The clinical experience of CAPD in 26 patients with ADPKD, treated for 11+/-6 months, was studied in retrospect and compared with that of 26 contemporary controls. Medical records were reviewed with respect to survival in this treatment form and any complication. Peritoneal dialysis capacity (PDC), as measured in 21 ADPKD patients and 20 controls, was also evaluated. University Hospital. Before initiation of CAPD, enlarged kidneys necessitated nephrectomy in 2 of 26 ADPKD patients; both cases were registered as preparation for transplantation, not for CAPD. Survival in CAPD was similar in ADPKD patients and controls. Hernia was present in 4 ADPKD patients and 2 controls, and required transfer to hemodialysis in 1 patient from each group, temporarily. The incidence of peritonitis was 1 per 20 months in ADPKD patients versus 1 in 27 months in the controls, not significantly different. Peritonitis was caused by colonic bacteria in similar numbers. Residual renal function was 1.9 2.1 mL/min per 1.73 m2 in ADPKD patients versus 1.9+/-1.4 mL/min per 1.73 m2 in the controls. No difference was detected in any of the variables measured by PDC. There were no specific problems related to ADPKD.

Assessing the peritoneal dialysis capacities of individual patients

A method for measuring the peritoneal dialysis capacity (PDC) of the individual patient has been developed as an aid to treatment of patients with renal failure and peritoneal dialysis. The patient collects the data him or herself during an almost normal CAPD day using a carefully designed protocol whereby the nursing time is kept to a minimum. The three-pore model is used to describe the PDC with three physiological parameters: (1.) the 'Area' parameter (A0/delta X), which determines the diffusion of small solutes and the hydraulic conductance of the membrane (LpS); (2.) the final reabsorption rate of fluid from the abdominal cavity to blood (JVAR) when the glucose gradient has dissipated; and (3.) the large pore fluid flux (of plasma, JVL), which determines the loss of protein to the PD fluid. In the adult PD population (age 60, N = 97) the normal 'Area' parameter was 23,600 cm/1.73 m2, with an SEM of 650. The JVAR was 1.49 ml/min/1.73 m2 and JVL was 0.078 ml/min/1.73 m2. The PDC parameters were reproducible and could adequately predict the concentrations of the test solutes as well as that of beta 2-microglobulin. The results in terms of clearance, 'UF volume' and nutritional consequences were presented on easily understandable graphs, whereby patient compliance was improved. These physiological parameters are highly dynamic, as evidenced by the marked increases observed during peritonitis. It seems safe to conclude that PDC is a useful tool to achieve adequate dialysis and to enhance the understanding of PD exchange.

Dialysis capacity of peritoneum in CAPD

Dialysis capacity of peritoneum in CAPD

Estimated frequency of acute and chronic renal insufficiencies in a Transdanubian region of Hungary.

The literature on the incidence of chronic and acute renal insufficiency is reviewed and the results of own investigations in an area with a population of 1,560,000 are presented. Data were collected in questionnaires. The yearly incidence of patients with chronic uraemia requiring active therapy was estimated at 33 per 1 million population. The number of acute cases was 45 per million. The necessity of increasing the dialysis capacity is stressed. The importance of peritoneal dialysis in the therapy of uraemia cases which do not meet the requirements of the acute and chronic dialysis programmes is emphasized.