Peritoneal Transport Type Research Articles

COMPARISON OF FAST PERITONEAL EQUILIBRIUM TEST WITH THE STANDARD METHOD: A PILOT STUDY

Standard peritoneal equilibrium test (PET) is an implementation that requires hard work for peritoneal dialysis (PD) staff. We analysed the efficacy of the fast PET and compared its results with standard PET. Forty-nine patients on PD therapy were included in the study. For standard PET, glucose, urea and creatinine values of dialysate were analysed at zeroth, second and fourth hours, and the patient's serum glucose, urea and creatinine values were analysed at second hour. In the fast PET, urea, glucose and creatinine values in plasma and dialysate were analysed at the fourth hour only. The results of both methods were compared with Pearson correlation and kappa tests. According to the standard PET, low transport in five patients, low-average transport in 17 patients, high-average transport in 23 patients and high transport types in four patients were identified. Fast PET results were similar in 46 (94%) patients (r = 0.77, p = 0.0001). Kappa (κw) analysis of results of both PETs was also statistically significant (p = 0.0001). This study showed that the peritoneal transport type may be determined more easily, practically and faster.

The importance of using peritoneal equlibration test for the peritoneal transport type characterization in continuous ambulatory peritoneal dialysis patients.

The aim of this study was to analyze the importance of the peritoneal equilibration test (PET) in evaluation of the peritoneal membrane transport status in patients treated with continuous ambulatory peritoneal dialysis (CAPD). The study included 30 adult continuous ambulatory peritoneal dialysis (CAPD) patients, 16 male and 14 female, mean age 61 +/- 16.5 years with a prescription of four exchanges of 2 litres (L) per day, who underwent peritoneal equilibration test (PET). Eleven of patients were diabetics. A modified PET was performed during a 4 hours dwell using 4.25% glucose dialysis solution. The dialysate/ plasma ratio of creatinine (D/P) at the end of the procedure, and the dialysate 240 min/ initial dialysate ratio of glucose (D/Do) were calculated and used as parameter of solute transport. With the test, categorization of patients was possible into high (H), high-average (HA), low average (LA), and low (L) transporters. In multivariate analysis age, gender, time on dialysis, comorbid diseases, diabetes mellitus (DM), serum albumin, were considered as independent factors influencing the PET. Among 30 patients 5 (16.7%) were classified as H transporters, 6 (20%) as HA, and 19 (63.3%) as LA. There were no patients in low category. Creatinine D/P at 4 hours was not different DM and non-DM patients. There were significant differences in gender, comorbid disease, serum albumin, D4/Do glucose and volume drained in 4 hours. The high transporter group had higher proportion of man (p<0.05), higher proportion of patients with comorbid diseases, lower serum albumin concentration (p<0.001), lower D4/Do glucose (p<0.001), and lower drained volume (p<0.001). The PET was en easy, inexpensive, reliable test to assess peritoneal transport type and it also provided information about peritoneal clearance of solutes and ultrafiltration. Peritoneal transport type classification was recognized not only as aid for prescription, but also as a prognostic index.

Factors associated with increased pulse wave velocity in peritoneal dialysis patients

Abstract Elevated pulse wave velocity (PWV) reflects increased arterial stiffness. Several studies have investigated PWV in peritoneal dialysis (PD) patients, but direct comparisons with healthy controls were not done. The potential influence of peritoneal transport characteristics on arterial stiffness in PD patients was suggested in recent studies. The aims of this study were to compare PWV in PD patients and healthy volunteers, and to investigate factors associated with increased PWV. The carotid-femoral PWV was measured in 28 PD patients and 28 healthy controls, matched for age and gender. A peritoneal equilibration test (PET) was performed in all PD patients. Based on the PET, patients were classified as: high transporters (H) (n=8), high-average (HA) (n=12), low-average (LA) (n=6), and low transporters (L) (n=2). Six of the PD patients were diabetic. PWV was significantly higher in the PD patients than in the controls (9,9±2,4 vs. 8,0±0,9; p=0,0004). In the PD group, PWV was higher in H/HA than in L/LA patients (10,4 ± 2,5 vs. 8,6 ± 1,0; p=0,008), but all the diabetic patients were in the H/HA group. PWV was significantly higher in diabetic than in non-diabetic PD patients (12,8 ± 2,0 vs. 9,1 ± 1,7; p=0,004). In the PD patients, significant positive correlations were found between PWV and: age, pulse pressure, Kt/V, and duration of PD therapy. In conclusion, the carotid-femoral PWV is elevated in peritoneal dialysis patients. Increased PWV in PD patients is associated with age, diabetic status, and longer duration of PD therapy, but not with this type of peritoneal transport.

Current Status of Children on Peritoneal Dialysis in Korea: A Cross-Sectional Multicenter Study

Purpose : Peritoneal dialysis (PD) is the major form of dialysis in use for infants and children with end-stage renal disease (ESRD). The aim of this study was to gain insight into the current status of children on PD in Korea. Methods : In May 2008, questionnaires were sent to the pediatric nephrologists via e-mail. Four centers replied and those data were reviewed. Results : A total of 103 patients were included in this study. Male to female ratio was 1.6:1. Mean age was 11.5±4.9 years (0-19 years). Primary renal diseases diagnosed were as follows: primary glomerular disease (34%), chronic pyelonephritis-reflux nephropathy (14.6%), systemic disease (9.7%), renal hypoplasia/dysplasia (8.7%), heredofamilial disease (6.8%), vascular disease (3.9%), drug-induced nephropathy (1.0%), and unknown (12.6%). PD modalities were as follows: CAPD (42.7%), CCPD (27.2%), NIPD (11.7%), and Hybrid (18.4%). Weekly total Kt/V was 2.1±0.7 (0.34.1). Results of peritoneal equilibrium test were as follows: low 36.8%, low average 31.6%, high average 19.7%, and high 11.8%. Z-score for weight was -1.00±1.20 (-4.54~+2.50). Z-score for height was -1.55±1.65 (-9.42~+1.87). Growth hormone was administered in 24.3% of patients. Anti-hypertensive drugs were administered in 64.0% of patients. Laboratory findings were as follows: hemoglobin 10.5±1.4 g/dL, calcium 9.7±0.7 mg/dL, phosphorus 5.4±1.4 mg/dL, and parathyroid hormone 324.2±342.8 pg/mL. Conclusion : Primary glomerular disease was the most common cause of ESRD. CAPD was the most prevalent PD modality. Low and low average peritoneal transport type were common. 1)

Relationship Between the −374T/A Receptor of Advanced Glycation End Products Gene Polymorphism and Peritoneal Solute Transport Status at the Initiation of Peritoneal Dialysis

An increased peritoneal solute transport rate (PSTR) at baseline is well known to be associated with decreased patient and technique survival in patients undergoing peritoneal dialysis (PD). Recently, angiogenesis has been recognized to be associated with PSTR and peritoneal deterioration. To investigate genetic variations in genes related to angiogenesis, 30 incident PD patients were studied. Several single nucleotide polymorphisms of the vascular endothelial growth factor (VEGF), the endothelial nitric oxide synthase (eNOS) and the receptor for advanced glycation end product (RAGE) were analyzed by the pyrosequencing method. The dialysate-to-plasma ratio of creatinine (D/P Cr) obtained from a peritoneal equilibrium test (PET) during the first 12 months after initiation of PD was used for a marker of PSTR. The D/P Cr was assessed both as a continuous and as a categorical variable including high (H), high-average (HA), low-average (LA), and low (L). Baseline D/P Cr was 0.645 +/- 0.083. The RAGE -374 TA genotype had a significantly lower prevalence of the H/HA transporters than the TT genotype (20% vs 63%; P = 0.03). Genetic polymorphisms of the VEGF and eNOS were not associated with initial peritoneal transport type. The RAGE polymorphism may have a considerable effect on the basal PSTR. Further studies will be needed to confirm this hypothesis.

Adequacy of automated peritoneal dialysis with and without manual daytime exchange: A randomized controlled trial

Until now, it remains unclear whether the addition of manual daytime exchanges or increasing the nightly dialysate flow is the best strategy to optimize automated peritoneal dialysis (APD) treatment. In this open-label randomized controlled crossover trial, 18 patients with high-average (HA) or low-average (LA) peritoneal transport rates sequentially underwent two different APD regimens for 7 days each, with an intermittent washout period of 7 days. 'Manual exchange' treatment was a conventional APD with low nightly dialysate flow and one manual daytime exchange. 'High-flow' treatment was defined by cycler therapy with high dialysate flow but without manual daytime exchange. Creatinine clearances (8.56+/-1.22 vs 7.87+/-1.04 l/treatment, P = 0.011) and urea nitrogen clearances (12.83+/-1.98 vs 11.68+/-1.06 l/treatment, P = 0.014) were significantly increased during 'high-flow' treatment compared to 'manual exchange' treatment. Sodium removal was significantly lower and glucose absorption was higher with the 'high-flow' regimen. Phosphate clearances, beta2-microglobulin clearances, ultrafiltration, and peritoneal protein loss were not different between the two treatment modalities. Subgroup analysis dependent on peritoneal transport types showed that the effect on clearances was most marked and significant in HA transporters, whereas sodium removal was lowest in LA transporters. We conclude that small solute clearances can be significantly improved and middle molecule clearances maintained in APD patients by increasing the nightly dialysate flow instead of adding a manual daytime exchange. However, the possible benefit of better clearances with higher nightly treatment volumes has to be weighed against increased costs and the possible negative impact of impaired sodium removal, especially in LA transporters.

Relationship of ENOS and RAS Gene Polymorphisms to Initial Peritoneal Transport Status in Peritoneal Dialysis Patients

Background: Peritoneal membrane permeability is of major importance for adequate dialysis and fluid balance in peritoneal dialysis (PD) therapy. The peritoneal capillary endothelium plays a key role in peritoneal transport. Nitric oxide derived from endothelial cells is related to the maintenance of vascular permeability. We investigated the relationship between the endothelial nitric oxide synthase (ENOS) gene polymorphism, the renin-angiotensin system (RAS) gene polymorphisms, and initial peritoneal transport type in PD patients. Methods: This study included 74 incident continuous ambulatory PD patients. The ENOS gene polymorphism was identified at the 4a/b variable number of tandem repeats in intron 4. Genetic polymorphisms of the renin-angiotensin system were performed for the angiotensin-converting enzyme I/D, angiotensinogen M235T, and angiotensin II type 1 receptor A1166C and type 2 receptor C3123A by polymerase chain reaction. Patients were divided into two groups according to the initial peritoneal equilibration test results performed within 3 months of PD therapy: group 1 consisted of high/high average transporters (n = 41), and group 2 consisted of low/low average transporters (n = 33). Results: Demographic, clinical, and laboratory data were similar between the two groups (p > 0.05). Group 1 had a significantly higher prevalence of the ENOS b/b genotype than group 2 (78% vs. 48.5%, p < 0.008). In contrast, group 2 had a significantly greater prevalence of the ENOS a/a+a/b genotype than group 1 (51.5% vs. 22%, p < 0.008). Genetic polymorphisms of the renin-angiotensin system were not associated with initial peritoneal transport type (p > 0.05). Conclusions: Modulation of the nitric oxide activity via the ENOS a/b polymorphism may have a considerable effect on the basal peritoneal permeability.

Peritoneal Transport Status Influence on Atherosclerosis/Inflammation in CAPD Patients

Peritoneal transport status is one of the main determinants of dialysis adequacy and dialysis-related complications in end-stage renal disease patients receiving continuous ambulatory peritoneal dialysis (CAPD). In this study we aimed to investigate the relationship between peritoneal transport characteristics and known promoters of atherosclerosis in a group of patients receiving CAPD for a minimum of 36 months. We performed a cross-sectional study of a cohort of 84 patients with end-stage renal disease (37 men, 47 women; age, 44.0 +/- 15.7 years; dialysis duration, 40.3 +/- 8.1 months) who were receiving CAPD for minimum 36 months. Peritoneal transport characteristics were identified after a peritoneal equilibration test (PET) determined at the third month of CAPD using Dialysate/Plasma (D/P) reference values. Patients were classified according to one of four peritoneal transport types: high (H), high-average (HA), low-average (LA), and low (L). After PET, patients were grouped as high (H/HA group, n = 51) or low (L/LA group, n = 33) transporters. The patient groups' clinical and laboratory data before dialysis and after initiation of the CAPD were collected retrospectively. The patients' follow-up data were retrieved for the diagnosis of any atherosclerosis-related event after the initiation of CAPD. The following events were collected, including myocardial infarction, having been diagnosed as having coronary artery disease by angiography or myocardium scintigraphy, cerebrovascular accident, and development of clinically evident peripheral arterial disease. A comparison of follow-up data revealed that the H/HA transport characteristic was associated with lower albumin (P < .01), higher C-reactive protein (CRP) (P < .0001) levels, and higher recombinant human erythropoietin (rHuEPO) needs (P < .001) when compared with the L/LA type. During follow-up, 28 patients showed an atherosclerosis-related event. Twenty-two of these were in the H/HA group (43.1%), whereas only six were in the L/LA group (18.1%, P < .01). Reanalysis of 18 patients with atherosclerosis-related events and high CRP levels (> 10 mg/L) showed that 15 were in the H/HA and 3 were in the L/LA group. Sixty-eight percent of the H/HA patients with atherosclerosis and 50% of the L/LA patients with an atherosclerotic event also had chronic inflammation (P < .001). A Pearson correlation analysis showed that there was a positive correlation between D/P creatinine levels and 36-month mean CRP levels (r = 0.608, P < .0001), and a negative correlation between D/P creatinine levels and 36-month mean albumin levels (r = -0.299, P < .005). This study shows that the high transporter peritoneal membrane characteristic is a risk factor for inflammatory state in patients with end-stage renal disease. High-transporter patients are at an increased risk of atherosclerosis when compared with their low-transporter counterparts through chronic inflammation.

Diálisis peritoneal: Correlación entre volumen, transporte peritoneal e hipertensión arterial

Objetivo: determinar si existe relación entre el volumen medido por bioimpedanciometría, el tipo de transporte peritoneal y la incidencia de hipertensión arterial (HA) en pacientes en diálisis peritoneal (DP).Materiales y métodos: se realizó un estudio de corte transversal. Se incluyeron 72 pacientes en DP del Hospital de San José a quienes se les midió el volumen de líquido corporal mediante bioimpedanciometría. Los pacientes fueron clasificados según las características del transporte peritoneal, establecido a través de la prueba de equilibrio peritoneal (PEP), en transportadores altos (TA), promedio (TP) y bajos (TB). Se evaluaron las cifras de tensión arterial, clasificando a los pacientes en normotensos, hipertensos controlados con hipotensores e hipertensos no controlados.Resultados: el exceso de agua fue de 2,98 +/- 2,36 L en TP y de 3,631L +/- 1,81 L en TA. En los pacientes normotensos, hipertensos controlados con medicación e hipertensos no controlados, se encontraron valores promedio de exceso de agua 3,16 L +/- 2,56, 2,79 L +/- 2,11 y 3,79 L +/- 2,39 L respectivamente. Se halló una frecuencia de normotensión de 28,1 %, hipertensión controlada de 56,1% y de hipertensión no controlada de 15,8 %. en los TP. En los TA estos valores fueron 10 %, 50% y 40% respectivamente. Conclusión: los TA tienden hacia un mayor exceso de líquido que los TP y tienen mayor frecuencia de HA no controlada. Esto podría explicar el exceso de mortalidad reportado en este grupo. El exceso de volumen independientemente del estado transportador, se relaciona con la presencia de HA.

Inflammation in patients on peritoneal dialysis is associated with increased extracellular fluid volume

Background Cardiovascular disorders (CD) are the most frequent cause of death in patients on dialysis. CD have been related to increased extracellular fluid volume, peritoneal transport type (PTT), hypertension, and inflammation. Inflammation is in itself a risk factor for mortality. The aim of this study was to assess the relationship of increased extracellular fluid volume, inflammation, and PTT in patients on continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD). Methods A cross-sectional study was carried out with 20 healthy controls (C), 21 patients on CAPD, and nine patients on APD. Clinical and demographic variables were measured and registered. Peritoneal equilibrium test (PET) was done. Blood volume (BV), total body water (TBW), inferior vena cava diameter during inspiration (IVCDi) and expiration (IVCDe), serum albumin, and serum C-reactive protein (CRP) were measured. Results All patients on peritoneal dialysis (PD) had at least one sign or symptom of increased extracellular fluid volume, hypertension being the most common. Patients also had higher TBW (C, 60.7 ± 7.2; APD, 62.6 ± 8.7; CAPD, 66.1 ± 8.3, as percentage of body weight, p <0.02), higher BV (C, 7.9 ± 1.6; APD, 9.8 ± 2.3; CAPD, 9.6 ± 2.3, as percentage of body weight, p <0.02), higher DIVCi (C, 2.9 ± 1.2; APD, 4.6 ± 2.5; CAPD, 4.5 ± 2.4 mm/m 2 BSA, p <0.02), and higher DIVCe (C, 6.2 ± 1.7; APD, 8.3 ± 3.4; CAPD, 8.0 ± 2.8 mm/m 2 BSA, p <0.05). PD patients also had hypoalbuminemia and higher CRP levels. There was significant positive correlation between CRP and DIVCi ( r = 0.43, p <0.05) and IVCe ( r = 0.45, p <0.05) and between serum albumin and creatinine dialysate-to-plasma ratio (D/P Cr, r = 0.57, p <0.01). Serum albumin and CRP were negatively correlated ( r = −0.54, p <0.02). Conclusions Patients on PD have increased extracellular fluid volume as compared with healthy controls. Hyperhydration is related to inflammation and to higher peritoneal transport types.

Inflammation in patients on peritoneal dialysis is associated with increased extracellular fluid volume

Cardiovascular disorders (CD) are the most frequent cause of death in patients on dialysis. CD have been related to increased extracellular fluid volume, peritoneal transport type (PTT), hypertension, and inflammation. Inflammation is in itself a risk factor for mortality. The aim of this study was to assess the relationship of increased extracellular fluid volume, inflammation, and PTT in patients on continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD). A cross-sectional study was carried out with 20 healthy controls (C), 21 patients on CAPD, and nine patients on APD. Clinical and demographic variables were measured and registered. Peritoneal equilibrium test (PET) was done. Blood volume (BV), total body water (TBW), inferior vena cava diameter during inspiration (IVCDi) and expiration (IVCDe), serum albumin, and serum C-reactive protein (CRP) were measured. All patients on peritoneal dialysis (PD) had at least one sign or symptom of increased extracellular fluid volume, hypertension being the most common. Patients also had higher TBW (C, 60.7 ± 7.2; APD, 62.6 ± 8.7; CAPD, 66.1 ± 8.3, as percentage of body weight, p <0.02), higher BV (C, 7.9 ± 1.6; APD, 9.8 ± 2.3; CAPD, 9.6 ± 2.3, as percentage of body weight, p <0.02), higher DIVCi (C, 2.9 ± 1.2; APD, 4.6 ± 2.5; CAPD, 4.5 ± 2.4 mm/m2 BSA, p <0.02), and higher DIVCe (C, 6.2 ± 1.7; APD, 8.3 ± 3.4; CAPD, 8.0 ± 2.8 mm/m2 BSA, p <0.05). PD patients also had hypoalbuminemia and higher CRP levels. There was significant positive correlation between CRP and DIVCi (r = 0.43, p <0.05) and IVCe (r = 0.45, p <0.05) and between serum albumin and creatinine dialysate-to-plasma ratio (D/P Cr, r = 0.57, p <0.01). Serum albumin and CRP were negatively correlated (r = −0.54, p <0.02). Patients on PD have increased extracellular fluid volume as compared with healthy controls. Hyperhydration is related to inflammation and to higher peritoneal transport types.

Bone Metabolism and Peritoneal Membrane Transport in Children on Chronic Peritoneal Dialysis

The aim of the study was to assess the influence of peritoneal membrane permeability on bone metabolism in dialyzed children. 24 children with end-stage renal failure and being treated with peritoneal dialysis (PD) were studied. The children were divided into two groups based on the results of a standard peritoneal equilibration test: group I, high peritoneal transport [ratio of dialysate glucose concentration at 4 hours to dialysate glucose concentration at 0 hours (D/D0) < 0.26, dialysate-to-serum ratio of creatinine concentration at 4 hours (D/P) > 0.81], 10 children aged 9.9 +/- 2.9 years; group II, other peritoneal transport types (D/D0 > 0.26, D/P < 0.81), 14 children aged 11.4 +/- 2.7 years. Serum levels of calcium (sCa), phosphorus (sP), protein, albumin, alkaline phosphatase (AP), and parathormone (PTH) were measured, and bone biopsies were performed in all children. Alfacalcidol and calcium carbonate doses were adjusted to sCa, sP, and PTH levels in all patients. No statistically significant differences (NS) between the two groups were found in age, duration of PD, sCa, sP, AP, PTH, protein, or albumin levels. The mean alfacalcidol dose was 0.055 +/- 0.057 microg/kg body weight/ week in group I and 0.099 +/- 0.065 microg/kg/week in group II (p = NS). In group I, the high peritoneal transport group, significantly lower osteoclast surface (OcS/BS) and bone formation rate (BFR/TV) were found compared with group 11 (3.1% +/- 1.7% vs 4.6% +/- 2.0%, and 483.5 +/- 329.2 microm3/mm2/day vs 913.9 +/- 558.3 microm3/mm2/day, respectively, p < 0.05). We also found significant positive correlation between D/D0 and BFR/TV and OcS/BS (r = 0.45, p < 0.05). Bone turnover in children treated with PD may depend on peritoneal permeability.

Dialysis adequacy and transport test for characterization of peritoneal transport type in chinese peritoneal dialysis patients receiving three daily exchanges

Dialysis adequacy and transport test (DATT) is an accurate method to classify peritoneal transport type for continuous ambulatory peritoneal dialysis (CAPD) patients with a regimen of four exchanges of 2 L/d. We examined the accuracy of DATT for the characterization of peritoneal transport type in patients with a regimen of three exchanges of 2 L/d, which is the standard CAPD regimen in Hong Kong Chinese. We studied 189 adult Chinese CAPD patients with a prescription of three exchanges of 2 L/d. Patients who had a peritonitis episode within the previous 30 days were excluded. Standard peritoneal equilibration test (PET) and DATT were performed on consecutive days. Correlation coefficients between dialysate-to-plasma ratios of creatinine (D/P) obtained for the PET and the DATT was 0.698 (P < 0.001). Peritoneal transport type was classified according to the reported D/P creatinine reference values obtained from the PET at 4 hours. When the result was compared with the transport type classified by the DATT result using the linear regression formula derived, the Cohen κ was 0.433 (95% confidence interval, 0.329 to 0.537), which could be regarded as a moderate level of agreement. For classification of the low transporters, the specificity of DATT was 90.1%, and sensitivity was 72.3%. For classification of the high transporters, the specificity of DATT was 96.6%, and sensitivity was 57.1%. DATT and PET had a reasonable agreement in the classification of peritoneal transport type for Chinese CAPD patients receiving a daily schedule of three exchanges of 2 L/d. Although DATT may be less accurate for CAPD patients with three daily exchanges, it remains a specific method to identify low and high transporters. © 2002 by the National Kidney Foundation, Inc.

Peritoneal Protein Loss in Patients with High Peritoneal Permeability: Comparison Between Continuous Ambulatory Peritoneal Dialysis and Daytime Intermittent Peritoneal Dialysis

Background Dialysate protein loss is involved in the etiology of hypoalbuminemia and malnutrition on continuous ambulatory peritoneal dialysis (CAPD). Patients with high peritoneal membrane permeability had the lowest serum albumin (Alb) and highest dialysate protein concentrations and achieved higher small solute dialysis/plasma equilibration in a shorter time than patients with low peritoneal transport. The aim of this prospective crossover study was to evaluate whether protein loss might be decreased in patients with high peritoneal permeability on short dwell-time (DT) peritoneal dialysis. Methods Five high and nine high-average peritoneal transport patients were subjected to the following sequential dialysis schemes (four exchanges/day, glucose 1.5%): scheme A, three daytime exchanges (4–6 h DT) and one nightly (8–12 h DT) for 2–3 days, scheme B, 3-h DT each and dry peritoneum at night during 5 days, a wash-out period similar to scheme A, and scheme C, 2-h DT each and dry peritoneum the remainder of day and night during 5 days. Dialysate Alb, IgG, IgA, and IgM losses and adequacy of dialysis were evaluated at the end of each scheme. Results Dialysate IgM was not detected. All protein losses were reduced with the short DT dialysis schemes; however, dialysis CCl and KT/V urea were also decreased. In patients with high peritoneal transport type, the 3-h DT dialysis scheme achieved a reduction in Alb loss without significant reduction of adequacy of dialysis. Conclusions Peritoneal Alb, IgG, and IgA losses are significantly reduced in patients with high peritoneal permeability on short dwell-time dialysis and extended dry periods. However, a reduction of dialysis contribution to small solute clearances was also observed, Three-hour dwell-time dialysis may be particularly useful in patients with high peritoneal transport type, as it tends to reduce peritoneal protein loss without notably reducing adequacy of dialysis.

Is high peritoneal transport rate an independent risk factor for CAPD mortality?

Is high peritoneal transport rate an independent risk factor for CAPD mortality? Patients with high peritoneal transport display the lowest serum albumin (SAlb) and the highest peritoneal protein loss. An association between high peritoneal membrane permeability and diabetes mellitus (DM) has been suggested. As malnutrition, hypoalbuminemia, and DM cause high mortality, it is probable that a high peritoneal transport rate is associated with high mortality on continuous ambulatory peritoneal dialysis (CAPD). The aim of the study was to identify whether a high peritoneal transport rate is an independent risk factor for mortality on CAPD. We included 167 patients with a peritoneal equilibration test that was performed between January 1994 and July 1997. The endpoint was the patient's status (alive, dead, or lost) in December 1997. Survival analysis was done by the Kaplan-Meier method and multivariate Cox proportional-hazard model. DM was significantly more frequent in the high (H) peritoneal transport type (20 out of 33) and was less frequent in the low (L) transport group (3 out of 18). SAlb (g/dL) was significantly lower as the peritoneal transport type was higher [H 2.7 +/- 0.5, high average (HA) 2.9 +/- 0.7, low average (LA) 3.2 +/- 0.6, and L 3.6 +/- 0.5]. Serum creatinine (SCr) was significantly higher in the L transport type (12.0 +/- 4.3 mg/dL) than in the other transport groups (H 8.7 +/- 3.1, HA 8.6 +/- 3.7, and LA 9.6 +/- 4.5). No other differences were found between peritoneal transport types. In the univariate analysis, high peritoneal transport rate, DM, low SCr, low SAlb, and older age significantly predicted mortality. However, in the multivariate analysis (chi2 = 40.55, P < 0.0001), only DM (b = 1.34, P = 0.0001), low SCr (b = -0.11, P = 0.02), and high peritoneal transport rate (b = 2.6, P = 0.06) were shown as mortality risk factors. DM was the most important risk factor for mortality on CAPD. A high peritoneal transport rate also predicted mortality, yet its role seems to be related to the presence of DM. The role of higher SCr predicting a better survival might have been associated with a better nutritional status. Hypoalbuminemia, previously shown as risk factor for mortality, did not play an important role in this study, probably because of its collinearity with DM.

Correlation between Peritoneal Equilibration Test and Dialysis Adequacy and Transport Test, for Peritoneal Transport Type Characterization

The aim of this study was to analyze the correlation between the peritoneal equilibration test (PET) and the dialysis adequacy and transport test (DATT) for peritoneal transport type characterization, and the degree of patients' acceptance for each test. Cross-sectional, observational multicenter study. Five referral (tertiary) dialysis centers of institutional practice. The study included 107 adult continuous ambulatory peritoneal dialysis (CAPD) patients with a prescription of four exchanges of 2 L per day, irrespective of age, gender, cause of end-stage renal disease, time on dialysis, nutritional status, or residual renal function. Patients on immunosuppressive therapy and those with cancer, hepatitis B, or HIV, and those having a peritonitis episode within the previous 30 days, or three or more episodes during the previous 12 months, were excluded. Peritoneal transport type as classified by creatinine and urea dialysis-to-plasma (D/P) ratios by PET and DATT. Correlation coefficients between D/P ratios for creatinine and urea, obtained for the PET and the DATT, were 0.73 for D/P creatinine and 0.96 for D/P urea. Patients were classified into high, high-average, low-average, and low transport categories according to the mean and standard deviation of D/P creatinine values obtained from the PET at 4 hours. These values showed excellent concordance with those generated from the DATT data (alpha = 0.82, 95% confidence interval 0.67 - 0.93). Nineteen percent of patients showed discordance in their category when classified according to the PET versus the DATT. Patients' acceptance was better for the DATT than for the PET, as evaluated with a questionnaire. The DATT is an easy, inexpensive, and reliable test to assess peritoneal transport type, and it also provides information about peritoneal clearance of solutes and ultrafiltration. The DATT has better patient acceptance than the PET. Since the DATT has only been validated for patients on a fixed CAPD daily schedule of 4 x 2 L, the results should be confined only to patients receiving such a prescription.

Tidal peritoneal dialysis for home-treated patients: should it be preferred?

Tidal peritoneal dialysis (TPD) was introduced to increase the efficacy of peritoneal dialysis. We measured peritoneal clearances of small solutes and beta2-microglobulin, peritoneal protein loss, and efficacy of ultrafiltration in 30 patients during TPD and intermittent peritoneal dialysis (IPD) with low-dialysate flow (1.7 L/h) and, in addition, in 17 of these patients using a high-dialysate flow (3 L/h). Using a low-dialysate flow, patients with low/low average peritoneal transport rates showed significantly better peritoneal creatinine and urea nitrogen clearances during IPD compared with TPD, whereas there was no difference between these two treatment modalities in high/high average transporters. With high-dialysate flow, peritoneal clearances of creatinine and urea nitrogen were similar between TPD and IPD independent of peritoneal transport type. Clearances of phosphate and beta2-microglobulin were similar between TPD and IPD independent of dialysate flow or peritoneal transport type. Increasing the dialysate flow rate led to a significant increase in small-solute clearances, but not beta2-microglobulin clearances, in both peritoneal transport types. Total peritoneal protein and albumin losses were similar between TPD and IPD only with low-dialysate flow. However, using a high-dialysate flow, total protein losses tended to increase in both transport types during IPD compared with TPD. In conclusion, up to a dialysate flow of 3 L/h, TPD did not provide better small-solute or middle-molecule clearances compared with IPD. Moreover, using a low-dialysate flow, IPD was superior to TPD in low/low average transporters.

Drain Volume Required for a Target Peritoneal Clearance

The authors developed formulae calculating the daily drain volume (DV) required for a target normalized peritoneal clearance of urea (Kt/V(ur)) or creatinine (Ccr, Kt/Vcr) in peritoneal dialysis (PD). DV depends on the target clearance, the peritoneal solute transport type, and the size of the person as expressed by body surface area (BSA) or body water (V). To illustrate the formulae, we constructed nomograms for the following weekly target clearances: Ccr = 60 L/1.73 m2, Kt/V(ur) = 2.0, Kt/Vcr = 1.8 (the value corresponding to a Ccr of 60 L/1.73 m2 in a linear regression of the two parameters in 476 clearance studies in continuous ambulatory PD [CAPD] patients). The PD schedules studied included CAPD, continuous cycling PD (CCPD) with one 2 L daytime dwell, and a combination of daytime CAPD and nighttime automated PD (APD) with 2 hr dwell times. Peritoneal transport was characterized as low, low-average, high-average, or high by the dialysate-to-plasma (D/P) creatinine concentration ratio in a peritoneal equilibration test (PET). The D/P value entered for each transport type was the appropriate 95% lower confidence limit of the mean D/P in actual studies (2 hr and 4 hr D/P from 102 PET studies and 5.5 hr D/P from 476 clearance studies in CAPD patients). For high transport, the required DV values were similar in all three PD schedules studied. For low transport, the required DV was much larger, comparatively, for CCPD and CAPD-APD than for CAPD. Furthermore, the DV values required for a weekly Kt/V(ur) of 2.0 were comparatively less than the DV values required for a weekly Kt/Vcr of 1.8 (Ccr of 60 L/1.73 M2). Calculation of the DV required for different PD schedules, a target peritoneal clearance, and the patients's size is feasible when the patient's peritoneal transport characteristics are known. This calculation also allows the selection of the least costly PD schedule. Current target values for urea and creatinine clearance are incompatible in anuric PD patients.

Peritoneal urea and creatinine clearances in continuous peritoneal dialysis patients with different types of peritoneal solute transport

We studied whether anuric subjects on continuous ambulatory peritoneal dialysis (CAPD) who achieve the target Kt/V urea of 2.0 weekly will also achieve the target normalized creatinine clearance (NCCr) of 60 liter/1.73 m2 weekly, and the reasons of discrepancy between the two clearances in anuric subjects, by analyzing 476 clearance studies performed in 309 CAPD patients within 12 months of the performance of a peritoneal equilibration test (PET). On the basis of the PET, peritoneal solute transport was classified as low (37 clearance studies), low-average (199 studies), high-average (186 studies) and high (54 studies). We found that weekly values of Kt/V urea in the low transport group (LTG) was 1.74 +/- 0.51, in the low-average transport group (LATG) was 1.66 +/- 0.41, in the high-average transport group (HATG) 1.68 +/- 0.41, and in the high transport group (HTG) 1.73 +/- 0.46 (NS, variance analysis). Weekly values for NCCr, liter/1.73 m2 were: LTG, 37.8 +/- 9.0; LATG, 44.0 +/- 9.2; HATG, 49.2 +/- 10.0; HTG 56.8 +/- 13.3 (P < 0.0001). The ratios of raw (not-normalized) peritoneal creatinine clearance to peritoneal urea clearance were: LTG, 0.65 +/- 0.14; LATG, 0.76 +/- 0.09; HATG, 0.84 +/- 0.09; HTG, 0.91 +/- 0.12 (P < 0.0001). Linear regression with Kt/V urea as x and NCcr as y revealed the following results: LTG, y = 19.486 + 10.500x, r = 0.591 [if x = 2.0, y = 15.004 + confidence interval (95% CI) of y 25.3 to 55.7]; LATG, y = 15.0004 + 17.482x, r = 0.774 (if x = 2.0, y = 50.0, 95% CI of y 38.4 to 61.6); HATG, y = 15.285 + 20.162x, r = 0.829 (if x = 2.0, y = 55.6, 95% CI of y 44.4 to 66.8); HTG, y = 14.945 + 24.134x, r = 0.839 (if x = 2.0, y = 63.2, 95% CI of y 48.4 to 78.1). Peritoneal solute transport type has a major effect on peritoneal creatinine clearance, but an insignificant effect on peritoneal urea clearance. Consequently, the majority of anuric patients who achieve a weekly Kt/V urea of 2.0 will have a weekly NC cr lower than 60 liter/1.73 m2 and will require a Kt/V urea much higher than 2.0 to achieve the target NCcr of 60 liter/1.73 m2 weekly. The current targets of urea and creatinine clearance are not compatible in anuric patients on CAPD.

Dialysis Dose Required for a Minimal Acceptable Level

To identify the most advantageous formula for estimating creatinine clearance (CCr) and to establish a dose of dialysis that will ensure minimal acceptable levels of creatinine clearance in patients on continuous peritoneal dialysis (CPD). Analysis of all CCr studies performed in CPD patients over 40 months. All four dialysis units following CPD patients in one city. One dialysis unit is government-owned, one is university-affiliated, and two are community based. One hundred and ninety-four patients representing almost the entire CPD population in Albuquerque. Creatinine and urea clearance studies were performed in 24-hour urine and drained dialysate samples. Creatinine clearance (peritoneal plus urinary) was normalized to either 1.73 m2 body surface area (CCr) or body water estimated by the Watson formulas (KT/VCr). CCr and KT/VCr were either corrected by averaging urinary creatinine and urea clearances or were not corrected. Two dialysis units were designated as the training set (92 patients, 143 clearance studies) and the other two units as the validation set (102 patients, 181 clearance studies). Minimal acceptable creatinine clearance levels were determined in the training set by computing the creatinine clearance value corresponding to 1.70 weekly KT/V urea by linear regression. Logistic regression models predicting low creatinine clearance were developed in the training set and were tested in the validation set. The following weekly creatinine clearance values corresponded to 1.70 KT/V urea: corrected CCr 52.0 L/1.73 m2, uncorrected CCr 54.4 L/1.73 m2, corrected KT/VCr 1.46, uncorrected KT/VCr 1.53. Logistic regression identified as predictors of low creatinine clearance low daily urine volume (UV) and low daily dialysate drain volume/body water (DV/V) for all four creatinine clearance formulas, plus low/low-average peritoneal solute transport (only for uncorrected CCr) and serum creatinine (for both KT/VCr formulas). In the validation set, the predictive models produced an area under the receiver operating characteristic (ROC) curve between 0.835 and 0.919 indicating very good predictive accuracy. For corrected CCr and anuria, the regression model produced a minimal normalized drain volume (DV/V) value consistent with minimal acceptable CCr equal to 0.305 L/L per 24 hours. This DV/V cutoff detected low corrected CCR in validation set anuric subjects (n = 55) with a sensitivity of 85% and a specificity of 71%. For uncorrected CCR and anuria, DV/V cutoffs were 0.273 L/L per 24 hours (high/high-average peritoneal solute transport) and 0.420 L/L per 24 hours (low/low-average transport). Sensitivity and specificity of these cutoffs in validation set anuric subjects were 87% and 85%, plus 86% and 33%, respectively. The uncorrected CCr appears to be the most advantageous creatinine clearance formula in CPD, because it allows the use of peritoneal solute transport type in the calculation of the minimal required normalized drain volume. The minimal acceptable uncorrected CCr is 54.4 L/1.73 m2 weekly. To achieve this uncorrected CCr in anuria, the required minimal normalized drain volume is 0.273 L per liter of body water daily if peritoneal solute transport is high or high-average and around 0.420 L per liter of body water daily if peritoneal solute transport is low or low-average. The required total daily drain volume is computed by multiplying the required normalized drain volume by body water.