Influence of exchange volume and dialysate flow rate on solute clearance in peritoneal dialysis.

To find the ideal dialysate flow rate and exchange volume for use in long-term peritoneal dialysis, 10 patients were studied over a period of 1.5 yr. Exchange volumes of 1 or 2 liters and dialysate flow rates of 1, 2, 3, 4, and 6 liters/hr were tested. Dextrose concentration remained constant at 1.5 g/100 ml. Peritoneal clearances for BUN, creatinine, and uric acid were calculated at 2, 5, 10, 15, and 20 hr during dialysis making a total of 120 clearances for each patient. All patients used a reverse osmosis automatic machine. The clearance of all three solutes tended to be higher with exchange volumes of 2 liters than they did with 1 liter; this trend was significant for BUN (P less than 0.025) and uric acid (P less than 0.025) but not for creatinine. There was a significant rise in clearance with increasing flow rates per hour for all solutes as shown in the following table. (Formula: see text), Since patients could not tolerate a flow rate of 6 liters/hr, we conclude that flow rate of 4 liters/hr with a 2-liter exchange will give maximum efficiency.     

Longitudinal changes of solute transport in peritonitis-free peritoneal dialysis patients

BACKGROUND: The aim of this study was to evaluate the longitudinal changes in peritoneal transport in patients on long-term, peritonitis-free, continuous ambulatory peritoneal dialysis (CAPD) therapy. METHODS: Results were longitudinally recorded for the standard peritoneal equilibration test (PET) in 76 consecutive, nondiabetic, adult patients from the beginning of CAPD therapy until their first episodes of peritonitis, abdominal surgery, or any cause of drop out. The PET results were evaluated once annually using the dialysate-to-plasma ratio of creati-nine (D/PCr) and the dialysate-to-instilled dextrose ratio (D4/D0) at 4 hours after beginning dialysis. RESULTS: A total of 168 PET results were obtained. A statistically significant tendency toward decreased D/PCr and increased D4/D0 values over time for up to 3 years was found. CONCLUSIONS: This study shows a tendency toward progressive decline in small molecular transport over time in nondiabetic patients with uneventful CAPD therapy. Sequential PET follow-up cannot be overlooked in peritonitis-free CAPD patients.     

Plasma and dialysate IL-6 and VEGF concentrations are associated with high peritoneal solute transport rate.

BACKGROUND: It has been speculated that increased levels of circulating or intraperitoneal pro-inflammatory cytokines such as interleukin 6, and pro-angiogenic vascular endothelial growth factor (VEGF) may contribute to high peritoneal small-solute transport rate (PSTR) in continuous ambulatory peritoneal dialysis (CAPD) patients. In this study we evaluated possible relationships between plasma and dialysate IL-6 and VEGF levels and PSTR. METHODS: Forty CAPD patients (mean age+/-SD of 58+/-14 years) with no apparent inflammation process or disease, who had been on CAPD for 19+/-15 months (range 3-56 months) were included in the study. Peritoneal equilibration test (PET) was used to evaluate PSTR. Patients were divided into two groups: high-average and high transporters (H/A; D/P(creat)>/=0.65) and low-average and low transporters (L/A; D/P(creat)<0.64). Albumin and IgG clearances were used in the evaluation of permeability to larger solutes. Plasma and overnight dialysate levels of IL-6 and VEGF were measured. RESULTS: Plasma IL-6 (7.6 vs 4.3 pg/ml) and VEGF (342 vs 163 pg/ml) as well as dialysate IL-6 (174 vs 80 pg/ml) and VEGF (96 vs 69 pg/ml) levels were significantly higher in the H/A than in the L/A group. The dialysate appearance of IL-6 and VEGF correlated with D/P(creat), as well as with albumin and IgG clearances. Moreover, significant correlations were noted between dialysate IL-6 and dialysate VEGF levels. CONCLUSIONS: The findings of (i) increased plasma and dialysate levels of IL-6 and VEGF in the H/A group compared to the L/A group, (ii) an association between PSTR and both plasma and dialysate IL-6 and VEGF levels, and (iii) a significant correlation between dialysate IL-6 and VEGF concentrations suggest that inflammation, angiogenesis, and peritoneal transport may be interrelated and involved in the pathophysiology of high PSTR in CAPD patients. However, due to the cross-sectional design of this study, the cause and effect relationships between plasma and dialysate IL-6 and VEGF concentrations and high PSRT remain unclear.     

Effect of papaverine on solute transport in peritoneal dialysis

Since vasodilators enhance the peritoneal solute transport, the influence of intraperitoneal papaverine was studied. To verify the action of papaverine on peritoneal transport we selected 33 patients on acute peritoneal dialysis and performed two 2-hour cycles with 2000 cc of a 1.5% solution, adding 40 mg of papaverine to the fourth cycle. At the end of the third and fourth cycles blood and dialysate were drawn for urea, creatinine, glucose and protein levels, using peritoneal clearances of urea and creatinine, glucose absorption and net protein loss to compare the two cycles. We found no significant change in solute transport (urea clearance p>0.0.5; creatinine clearance, protein loss and glucose absorption p>0.1).     

Impact of low calcium dialysate on survival in continuous ambulatory peritoneal dialysis patients

Objective To investigate the impact of low calcium dialysate on survival in continuous ambulatory peritoneal dialysis（CAPD）patients. Methods CAPD patients at our PD center between January 1,2006 and December 31,2010 were retrospectively studied. The patients were divided into standard - calcium dialysate (SCD) group and low - calcium dialysate (LCD) group. Cox regression analysis was used to compare patient survival and determine the related risk factors Results A total of 982 eligible PD patients were included in this study, of whom 634 patients treated with standard-calcium dialysate, and 348 with low-calcium dialysate. During a median follow-up of 24.2 - month, 162(16.5% ) died, 71(43.8% ) of them due to cardiovascular and cerebrovascular diseases. The overall 1-, 3-, and 5-year patient survival rates were 90.9%, 74.2% and 58.9% in SCD group and 98.6%, 94.0% and 76.4% in LCD group. Cox regression analysis demonstrated that low calcium dialysate treatment reduced 59% risk of all-cause death, as compared with standard calcium dialysate exposure. Old age, diabetes status and lower hematoglobin were independent risk factors of all - cause death in CAPD patients. Conclusion The survival rate of CAPD patients using LCD is obviously higer than that using SCD. Old age, diabetes status and lower haematoglobin are independent risk factors of all-cause death in CAPD patients.     

重新评价腹膜平衡试验以确定腹膜透析患者的溶质转运类型

目的 确定由Twardowski提出的腹膜平衡试验（PET）的转运类型评判值是否适合本中心患者。方法 选取我院自1995年来首次进行PET测试的患者158例。首先依据Twardowski的评判标准（值）判断患者的转运类型,再根据本组患者实际4hD/Pcr的χ±s来确定患者的溶质转运类型,然后将患者重新分组:按两种数值均符合高转运为H1组,均符合平均转运为A组,均符合低转运为L1组,部分高转运患者经重新评价后符合平均转运为H2组,部分平均转运患者经重新评价后符合低转运为L2组。通过与临床情况（溶质和水的清除）进行对照,以进一步评价更适合本中心患者的评判标准。结果 按照Twardowski的标准,高转运、高平均转运、低平均转运及低转运患者的比例分别为21.5％、44.9％。27.8％及5.7％。本研究患者群中4hD/Pcr的均值和标准差为0.70和0.14,据此重新评判后,各组的比例分别为14.6％、33.5％、33.5％及18.4％。经与临床结果相对比,L2组对水份的清除能力明显高于A组（P<0.005）,与L1组差别无显著性意义。结论4hD/Pcr在不同的地区和人群中表现出不同的均数和标准差值,因而产生了不同的腹膜转运类型。根据本中心患者人群确定的值更适合本中心患者的临床情况。     

Longitudinal relationship between solute transport and ultrafiltration capacity in peritoneal dialysis patients

BACKGROUND: Time on treatment is associated with a greater risk of impaired ultrafiltration (UF) in peritoneal dialysis (PD) patients. In addition to increasing solute transport, a potentially treatable cause of impaired ultrafiltration, cross-sectional studies suggest that there is also reduced osmotic conductance of the membrane. If this were the case then it would be expected that the UF capacity for a given rate of solute transport would change with time. The purpose of this analysis was to establish how solute transport and UF capacity change relative to one another with time on therapy. METHODS: Membrane function, using a standard peritoneal equilibration test, was measured at least annually in a well-characterized, single-center observational cohort of PD patients between 1990 and 2003. Demography included age, gender, original cause of renal failure, body surface area (BSA), validated comorbidity score, residual urine volume and urea clearances, peritoneal urea clearances, and plasma albumin. RESULTS: Data from 574 new PD patients were available for analysis. Independent demographic factors associated with higher solute transport at baseline were male gender and higher residual urine volume. Throughout time on therapy there was a negative relationship between solute transport and UF capacity and a significant increase and decrease in these parameters, respectively. During the first 12 months of treatment, the increase in solute transport was not associated with the expected fall in UF capacity, a phenomenon that was not explained by informative censoring, but was associated with an increased, albeit weak, correlation with BSA. In contrast, later in treatment there was a disproportionate fall in UF capacity, more accelerated in patients developing UF failure. Early exposure to higher intraperitoneal glucose concentrations, in the context of more comorbidity and relative lack of residual renal function, was associated with more rapid deterioration in membrane function. CONCLUSION: Despite a causal link between solute transport and UF capacity of the membrane, due to the effect of the former on the osmotic gradient, there is evidence of their longitudinal dissociation. This implies a change in the structure-function relationship with time on treatment that can, to some extent, be predicted from clinical factors present within the first year of treatment. Dialysis-induced membrane injury must involve at least two processes, for example, increased vascular surface area contact with dialysate combined with changes in hydraulic conductance due to scarring of the vessels and interstitium.     

Leptin in peritoneal dialysate from continuous ambulatory peritoneal dialysis patients.

The adipocyte-derived hormone leptin is the 16-kd product of the ob gene that regulates food intake and body weight. Plasma leptin level is elevated in patients with chronic renal failure, partly because of impaired clearance through the kidney. In this study, we examined whether leptin is cleared into peritoneal dialysate in patients with end-stage renal disease treated by continuous ambulatory peritoneal dialysis (CAPD). The subjects were 46 CAPD patients and 67 age- and gender-matched healthy subjects. Leptin concentration in peritoneal dialysate from CAPD patients was measurable by a sensitive enzyme-linked immunosorbent assay (ELISA), and the daily loss of leptin by the peritoneal route was estimated to correspond to the amount contained in approximately 2 L plasma. Dialysate leptin concentration correlated positively with plasma leptin level and with percent body fat measured by dual-energy X-ray absorptiometry. The dialysate-to-plasma (D/P) ratio of leptin concentration was twice higher than expected from its molecular weight. D/P ratios of beta2-microglobulin, albumin, and transferrin showed strong correlations with each other (r = 0.768 to 0.801), whereas the correlation between D/P ratios of leptin and beta2-microglobulin was less impressive (r = 0.378). This was also the case with the relationship between apparent peritoneal clearances of these macromolecules, suggesting that dialysate leptin had some origins other than passive transport of plasma leptin. To test the hypothesis that abdominal visceral fat may contribute to the unexpectedly raised peritoneal dialysate leptin concentration, multiple regression analysis was performed. Leptin concentration in peritoneal dialysate showed significant association with plasma leptin level and D/P ratio of beta2-microglobulin, and it also showed an independent association with abdominal visceral fat but not with subcutaneous fat assessed by ultrasonography. These results showed that peritoneal dialysate from CAPD patients contained a significant amount of leptin, which derived presumably from both plasma and local visceral fat tissue.     

Baseline peritoneal solute transport rate is not associated with markers of systemic inflammation or comorbidity in incident Korean peritoneal dialysis patients.

BACKGROUND: It is controversial whether comorbid status or systemic inflammation has an influence on the peritoneal solute transport rate (PSTR). Our aim is to elucidate whether baseline PSTR is associated with markers of systemic inflammation or degree of comorbidity in incident peritoneal dialysis (PD) patients. METHODS: One hundred and ninety-five incident PD patients were prospectively included. Results of their baseline peritoneal equilibration test (PET) using 3.86% glucose PD fluid were analysed. Clinical and laboratory parameters of inflammation, comorbidity, nutritional status, dialysis adequacy and residual renal function (RRF) were assessed at the time of PET. RESULTS: Mean dialysate-to-plasma ratio for creatinine at 4 h (D/Pcr(4)) of our patients was 0.72 +/- 0.11. High-sensitivity C-reactive protein (hsCRP), serum interleukin-6 (IL-6) and serum albumin concentrations were closely interrelated to one another and these markers of systemic inflammation were also related to the Davies comorbidity score. No differences in age, sex ratio, body mass index, body surface area and presence of diabetes were found among four transport groups. RRF, total Kt/V, haemoglobin, nitrogen appearance and the Davies comorbidity score were not different either. High-sensitivity CRP, serum IL-6 and albumin concentrations were not associated with the baseline PSTR. By multiple linear regression analysis, only the serum albumin concentration measured at the time of PET (beta = -0.081 +/- 0.020, P < 0.001) remained significantly associated with D/Pcr(4). CONCLUSION: In our study with incident Korean PD patients, the baseline PSTR was not influenced by markers of systemic inflammation or comorbidity. For a subgroup of PD patients without serious comorbidity, other mechanisms of high baseline PSTR need to be elucidated.     

自我调节疲劳对腹膜透析患者疾病管理积极度的影响

目的分析自我调节疲劳对腹膜透析患者疾病管理积极度水平的影响。方法采用患者积极度量表、自我调节疲劳量表对241例腹膜透析患者进行调查。结果患者积极度总分(56.52±9.16)分,整体处于第三水平,其中第一水平35例(14.5%),第二水平75例(31.1%),第三水平100例(41.5%),第四水平31例(12.9%);自我调节疲劳总分(41.78±9.76)分。有序多分类Logistic回归分析结果显示,文化程度、家庭人均月收入是腹膜透析患者积极度水平的保护因素,血肌酐、自我调节疲劳是其危险因素(均P0.01)。结论腹膜透析患者疾病管理积极度水平整体较高,但其普遍缺乏参与自我照护的信心,其自我调节疲劳水平高于正常人群。护理人员应帮助患者疏导负性体验,保持积极自我调节,增强自我照护的信心。     

Effect of increased dialysate volume on peritoneal surface area among peritoneal dialysis patients

Large dialysate volumes are often required to increase solute clearance for peritoneal dialysis patients. The resulting increase in solute clearance might be attributable to an increased plasma-to-dialysate concentration gradient and/or to an increased effective peritoneal surface area. One of the factors affecting the latter is the peritoneal surface area in contact with dialysate (PSA-CD). The aim of this study was to estimate the change in PSA-CD after a 50% increase in the instilled dialysate volume for patients undergoing peritoneal dialysis. PSA-CD was estimated by using a method applying stereologic techniques to computed tomographic (CT) scans of the peritoneal space. The peritoneal cavity of 10 peritoneal dialysis patients was filled with a solution containing dialysate, half-isotonic saline solution, and contrast medium. Peritoneal function tests and CT scanning of the abdomen were performed twice for each patient (with an interval of 1 wk), after instillation of a 2- or 3-L solution. Scanning of thin helical CT sections was performed, and 36 random sections of the abdomen were obtained after reconstruction. A grid was superimposed on the sections. The surface area was estimated by using stereologic methods. After instillation of the 2-L solution, the volume of the peritoneal solution at the time of CT scanning was 2.32 +/- 0.05 L. The PSA-CD was 0.57 +/- 0.03 m(2), ranging from 0.41 to 0.76 m(2). The use of the 3-L solution increased the peritoneal volume by 46 +/- 2%. PSA-CD increased by 18 +/- 2.3% to 0.67 +/- 0.04 m(2) (range, 0.49 to 0.84 m(2); P < 0.01). Creatinine mass transfer increased from 112 +/- 10 mg to 142 +/- 11 mg (P < 0.0001). The slope of the change of the plasma-to-dialysate creatinine concentration gradient with time decreased from -2.26 +/- 0.23 x 10(-2) to -1.97 +/- 0.16 x 10(-2) (P = 0.01). K(BD-0) (permeability-surface area product or mass area transfer coefficient at time 0 of the dwell) increased from 10.6 +/- 0.7 to 13.6 +/- 1.2 ml/min (P < 0.02). These data demonstrate that increasing the instilled dialysate volume by 50% for peritoneal dialysis patients results in significant increases in the PSA-CD and K(BD).     

Serum and peritoneal dialysate thyroid hormone levels in patients on continuous ambulatory peritoneal dialysis

Thyroid function tests were performed on 16 clinically euthyroid patients with end-stage renal failure undergoing regular haemodialysis or continuous ambulatory peritoneal dialysis and compared with 8 healthy subjects. The patient groups were carefully matched, especially regarding relative duration of dialysis (mean of 24 months). Total serum thyroxine, total triiodothyronine, free thyroxine, free triiodothyronine and reverse triiodothyronine were significantly lower in both patient groups than control. The thyrothrophin response to the standard thyrotrophin-releasing hormone test was delayed and blunted. Using a novel concentration technique we measured loss of T4 in peritoneal dialysate effluent and found it to be approximately 10% of daily thyroidal T4 release.     

Increases in peritoneal small solute transport in the first month of peritoneal dialysis predict technique survival

BACKGROUND: Peritoneal transport of small solutes generally increases during the first month of peritoneal dialysis (PD). The aim of this study was to prospectively evaluate the ability of the peritoneal equilibration test (PET), carried out 1 and 4 weeks after the commencement of PD, to predict subsequent technique survival. METHODS: Fifty consecutive patients commencing PD at the Princess Alexandra Hospital between 1 February 2001 and 31 May 2003 participated in the study. Paired 1 week and 1 month PET data were collated and correlated with subsequent technique survival. RESULTS: A significant increase was observed in the dialysate : plasma creatinine ratio at 4 h (D/P Cr) between 1 and 4 weeks after the onset of PD (0.55 +/- 0.12 vs 0.66 +/- 0.11, P <0.001). Mean death-censored technique survival was superior in patients who experienced > or =20% rise in D/P Cr during the first month of PD compared with those who did not (2.3 +/- 0.2 vs 1.6 +/- 0.2 years, P <0.05). Using a multivariate Cox proportional hazards model analysis, the significant independent predictors of death-censored technique survival were an increase in D/P Cr of greater than 20% during the first month (adjusted hazard ratio [HR] 0.20, 95% CI 0.05-0.75), the absence of diabetes mellitus, the absence of ischaemic heart disease, body mass index and baseline peritoneal creatinine clearance. CONCLUSIONS: A 20% or greater rise in D/P Cr during the first month of commencing PD is independently predictive of PD technique survival. Further investigations of the mechanisms underlying this phenomenon are warranted.     

Associates of mortality among peritoneal dialysis patients with special reference to peritoneal transport rates and solute clearance.

The current report describes the distributions of selected demographic and biochemical parameters, clearance, and other transport values among patients undergoing peritoneal dialysis (PD) and evaluates the associates of mortality using those values, with and without clearance and peritoneal equilibration test (PET) data. All patients receiving PD on January 1, 1994 were selected (n = 2,686). Patients who switched to another form of dialysis during the study period were removed from the study at the time of therapy change. Working files were constructed from the clinical database to include demographic, laboratory, and outcome data. Laboratory data were available in only 1,603 patients and were used to evaluate the biochemical associates of mortality after merging the biochemical, demographic, and outcome data. Patients with clearance data or PET studies underwent a second analysis to assess the effects of peritoneal and renal clearance on survival. The analysis of demographic and laboratory data confirmed the importance of age and serum albumin concentration as predictors of death. Residual renal function (RRF) was strongly correlated with survival, but peritoneal clearance was not. Several possible explanations for the lack of correlation between peritoneal clearance and survival are discussed. The data suggest that RRF and peritoneal clearance may be separate and not equivalent quantities. Substantial work is required to confirm or refute these findings, because the information is essential to establish the adequate dose of PD in patients with various degrees of RRF.     

Association of dialysate calcium concentration with fetuin a level and carotid intima-media thickness in peritoneal dialysis patients

Serum fetuin A has been shown to be associated with the risk of vascular calcification and atherosclerosis, and it can predict the onset of cardiovascular mortality in dialysis patients. The carotid intima-media thickness (cIMT) is an accessible and reliable method to identify the subclinical atherosclerosis. The aim of this study was to investigate the relationships between dialysate calcium concentrations and fetuin A or cIMT in patients undergoing peritoneal dialysis (PD). Forty patients, newly diagnosed end-stage renal disease (ESRD) and undergoing peritoneal dialysis, were enrolled in the study, with a calcium content of the peritoneal dialysis (PD) solution of 1.25?mmol/L in 20 patients (low-Ca group) and 1.75?mmol/L in 20 patients (standard-Ca group). The patients were followed up for 12 months after the PD conducted. Serum fetuin A was determined using a human fetuin A enzyme-linked immunosorbent assay kit and cIMT was detected using ultrasonic wave. We observed no difference between two groups with regard to the baseline data of fetuin A, cIMT, calcium, phosphorus, calcium-phosphorus product, high sensitivity CRP (hsCRP), parathyroid hormone (PTH), or lipid parameters. After 12 months follow-up, fetuin A (263.92?±?16.1 vs. 282.76?±?21.0, p?=?0.017) and calcium-phosphorus product (39.85?±?7.76 vs. 47.50?±?6.65, p?=?0.009) were obviously lower in the low-Ca group than standard-Ca group, the other serum parameters were not different between these two groups. Compared with baseline data, serum fetuin A concentration significantly reduced in low-Ca group (?p?p?相似文献   

Peritoneal glucose exposure and changes in membrane solute transport with time on peritoneal dialysis

Peritoneal solute transport increases with time on treatment in a proportion of peritoneal dialysis (PD) patients, contributing to ultrafiltration failure. Continuous exposure of the peritoneum to hypertonic glucose solutions results in morphologic damage that may have a causative role in changes in peritoneal function. The purpose of this analysis was to establish whether increased exposure to glucose preceded changes in solute transport in a selected group of long-term PD patients. Peritoneal solute transport, residual renal function, peritonitis rate, and peritoneal exposure to glucose were recorded prospectively in a cohort of 303 patients at a single dialysis center. A subgroup of individuals, treated continuously for 5 yr, were identified and defined retrospectively as having either stable or increasing transport status. Of the 22 patients who were treated continuously for 5 yr, 13 had stable solute transport (solute transport at start, 0.67 [+/-0.1]; at 5 yr, 0.67 [+/-0.1]), whereas 9 had a sustained increase (solute transport at start, 0.56 [+/-0.08]; at 5 yr, 0.77 [+/-0.09]). Compared with the stable patients, those with increasing transport had earlier loss in residual renal function and were exposed to significantly more hypertonic glucose during the first 2 yr of treatment that preceded the increase in solute transport. This was associated with greater achieved ultrafiltration compensating for the reduced urinary volumes in these patients. Further increases in glucose exposure were observed as solute transport continued to rise. Peritonitis, including severity of infection and causative organism, was similar in both groups. In this selected group of long-term survivors on PD, an increase in solute transport with time was preceded by increased peritoneal exposure to hypertonic glucose. This is supportive evidence that hypertonic glucose may play a causative role in alterations in peritoneal membrane function.     

Plasma interleukin-6 levels in continuous ambulatory peritoneal dialysis and hemodialysis patients.

Plasma levels of interleukin-6 (IL-6), a cytokine known to be involved in lymphocyte activation and in inflammation, were studied in 10 normal volunteers, 21 continuous ambulatory peritoneal dialysis (CAPD) patients and 41 hemodialysis patients. Plasma IL-6 levels in hemodialysis patients were significantly higher than those in normal volunteers and CAPD patients (p less than 0.05). The means of plasma IL-6 concentrations before and after hemodialysis did not change significantly. While IL-6 in peritoneal dialysate was detectable in only 3 of the 21 CAPD patients without peritonitis, it was extremely high in 2 patients with bacterial peritonitis. IL-6 levels decreased as peritonitis subsided.