A quantitative description of solute and fluid transport during peritoneal dialysis.

To investigate the relationship between dialysate glucose concentration and peritoneal fluid and solute transport parameters, 41 six-hour single dwell studies with standard glucose-based dialysis fluids containing 1.36% (N = 9), 2.27% (N = 9) and 3.86% (N = 23) anhydrous glucose were carried out in 33 clinically-stable continuous ambulatory peritoneal dialysis (CAPD) patients. Intraperitoneal dialysate volumes (VD) were determined from the dilution of 131I-albumin with a correction applied for its elimination from the peritoneal cavity (KE, ml/min). Diffusive mass transport coefficients (KBD) were calculated from aqueous solute concentrations (with a correction applied for the plasma protein concentration and, for electrolytes, also for the Donnan factor) during a period of dialysate isovolemia. The intraperitoneal amount calculated to be transported by diffusion was subtracted from the measured total amount of solutes in the dialysate, yielding an estimate of non-diffusive solute transport. The intraperitoneal dialysate volume over time curve was characterized by: initial net ultrafiltration (lasting on average 92 min, 160 min and 197 min and with maximum mean net ultrafiltration rates 6 ml/min, 8 ml/min and 14 ml/min, respectively, for the 1.36%, 2.27% and 3.86% solutions); dialysate isovolemia (lasting about 120 min for all three solutions) and fluid reabsorption (rate about 1 ml/min for all three solutions). KBD for glucose, potassium, creatinine, urea and total protein did not differ between the three solutions and the fractional absorption of glucose was almost identical for the three glucose solutions, indicating that the diffusive transport properties of the peritoneum is not influenced by the initial concentration of glucose or the ultrafiltration flow rate. About 50% of the total absorption of glucose occurred during the first 90 minutes of the dwell. The mean percentage of the initial amount of glucose which had been absorbed (%GA) at time t during the dwell could be described (r = 0.999) for all three solutions using the experimental formula %GA = 85 - 75.7 * e-0.005*t. After 360 minutes, about 75% of the initial intraperitoneal glucose amount had been absorbed corresponding to a mean (+/- SD) energy supply of 75 +/- 6 kcal, 131 +/- 18 kcal and 211 +/- 26 kcal for the three solutions. Non-diffusive (that is, mainly convective) transport was almost negligible for the less hypertonic solutions while it was estimated to account for 30 to 40% of the total peritoneal transport of urea, creatinine and potassium during the first 60 minutes of the 3.86% exchange.     

Peritoneal transport in CAPD patients with permanent loss of ultrafiltration capacity

During a 10 year period, 14 out of 227 patients (6.2%) undergoing continuous ambulatory peritoneal dialysis (CAPD) developed permanent loss of ultrafiltration capacity (UFC). The risk of UFC loss increased from 2.6% after one year to 30.9% after six years of treatment. A six hour, single dwell study with glucose 3.86% dialysis fluid was carried out in nine of the UFC loss patients and in 18 CAPD patients with normal UFC. Intraperitoneal dialysate volumes were calculated using 131I-tagged albumin (RISA) as volume marker with a correction applied for its elimination from the peritoneal cavity. The RISA elimination coefficient (KE), which can serve as an estimation of the upper limit of the lymphatic flow, was also calculated. Diffusive mass transport coefficients (KBD) for investigated solutes (glucose, creatinine, urea, potassium, total protein, albumin and beta 2-microglobulin) were calculated during a period of dialysate isovolemia. Two patterns of UFC loss were observed: (a) seven patients had high KBD values for small solutes resulting in rapid uptake of glucose, whereas KBD values for proteins were normal; (b) two patients had normal KBD values but a threefold increase both in the fluid reabsorption rate and KE. We conclude that loss of the osmotic driving force (due to increased diffusive mass transport for small solutes) and increased fluid reabsorption (possibly due to increased lymphatic reabsorption) are the two major causes of permanent loss of UFC in CAPD patients.     

Inhibition of cytokine synthesis by peritoneal dialysate persists throughout the CAPD cycle.

The current study focused on the effect of continuous ambulatory peritoneal dialysis (CAPD) dialysate obtained following different intraperitoneal dwell periods on the release of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF alpha) from mononuclear leukocytes (PBMC). Aliquots of 5 x 10(6)/ml healthy peripheral PBMC were exposed to fresh or spent CAPD dialysate (10-240 min of intra-peritoneal dwell) and stimulated with Escherichia coli endotoxin (10 micrograms/ml, 2h). IL-6 and TNF alpha in cell supernatants were determined by specific enzyme immunoassays. Control PBMC in physiological buffer released 361 +/- 70 pg/ml IL-6 and 717 +/- 147 pg/ml TNF alpha (mean +/- SEM, n = 8), whereas exposure to fresh dialysis fluids severely suppressed cytokine release from PBMC (less than 30 pg/ml IL-6 and less than 15 pg/ml TNF alpha). A significant inhibition of IL-6 and TNF alpha release was also observed in PBMC exposed to spent dialysate. The inhibitory capacity of the spent fluids was pronounced with increasing intra-peritoneal dwell time (10 min: 183 +/- 45 pg/ml IL-6 and 538 +/- 109 pg/ml TNF alpha; 240 min: 26 +/- 5 pg/ml IL-6 and 105 +/- 30 pg/ml TNF alpha; mean +/- SEM, n = 16). These data indicate that the impairment of cell responsiveness following exposure of PBMC to peritoneal dialysate is not restricted to the unused fluids, but is also observed following intra-peritoneal equilibration. Moreover, our findings suggest the presence of cytokine inhibitory factors in the peritoneal dialysate of CAPD patients which appear to accumulate in the peritoneal effluent during the CAPD cycle.     

Kinetics of peritoneal dialysis in children: role of lymphatics

Intraperitoneal fluid is absorbed continuously by convective flow into the peritoneal cavity lymphatics. We evaluated the role of lymphatic absorption in the kinetics of peritoneal dialysis during standardized four hour exchanges in six children using 40 ml/kg of 2.5% dextrose dialysis solution. Cumulative lymphatic absorption averaged 10.4 +/- 1.6 ml/kg and reduced the total net transcapillary ultrafiltration during the dwell time by 73 +/- 10%. Due to the considerable lymphatic absorption rate, maximum intraperitoneal volume was observed before osmolar equilibrium. Extrapolated to four study exchanges per day, lymphatic absorption decreased the potential daily drain volumes in the children by 27 +/- 5% and daily peritoneal urea and creatinine clearances by 24 +/- 4% and 22 +/- 5%, respectively. Compared with four hour exchanges using two liters of 2.5% dextrose dialysis solution in 10 adult CAPD patients with average peritoneal transport, the children had more rapid equilibration of urea, greater absorption of dialysate glucose, higher lymphatic absorption and lower net ultrafiltration (P less than 0.01 to P less than 0.05). Lymphatic absorption therefore causes a relatively greater reduction in net ultrafiltration and solute clearances in children than in adults.     

Evaluation of an experimental rat model for peritoneal dialysis: fluid and solute transport characteristics

The aim of this study was to develop a reference model of fluidand solute transport during experimental peritoneal dialysisin rats, which would simulate the conditions of clinical dialysisin CAPD patients as much as possible. For this purpose a 4-hdialysis study was performed in 13 normal Sprague-Dawley ratswith conventional glucose solutions (Dianeal 1.36% solution,n=6 and Dianeal 3.86% solution, n=7) and a protocol and methodslike those used in clinical dwell studies. The dilution of amarker, radioactive human serum albumin (RISA), was used todetermine the intraperitoneal dialysate volume with correctionsfor the elimination of RISA from the peritoneal cavity and samplevolumes. The isovolumetric method was employed to calculatethe diffusive mass transport coefficients. To compare our datawith reference values in CAPD patients, the data were scaledby a factor calculated as a ratio of the dialysate volume inCAPD to the dialysate volume in the rats. In a separate seriesof experiments the intraperitoneal hydrostatic pressure wasmonitored with increasing infusion volumes. The fluid transport characteristics, described as the percentagechanges of the initial intraperitoneal volume, were essentiallycomparable to those in CAPD patients. However, the intraperitonealvolume curves were shifted more to the left than were the reportedvalues in CAPD patients. The scaled diffusive mass transportcoefficient for urea was similar to that in CAPD patients. However,the transport of other solutes, in particular glucose, was fasterin the rats than in CAPD patients. The intraperitoneal hydrostaticpressure increased exponentially with increasing infusion volumerelative to body weight and was 0.3–0.9 mmHg with thestandard infusion volume of 30 ml in the present study. Theintraperitoneal hydrostatic pressure in the rats receiving 30mi of fluid intraperitoneally was lower than the reported intraperiCorrespondencetoneal pressure in CAPD patients using 2 1 of dialysis fluid. We conclude that the present experimental model of peritonealdialysis in the rat with a protocol and methods similar to thoseused in clinical studies, after appropriate scaling, seems tohave fluid and solute transport characteristics that resembledthose in clinical peritoneal dialysis, but considerable differenceswere also found.     

腹膜转运特性明显影响艾考糊精腹透液的超滤量

目的 观察不同腹膜转运特性的患者使用7.5%艾考糊精腹透液长时间留腹后的超滤量。 方法 采用前瞻性、多中心、随机、双盲和平行对照临床研究的亚组分析。连续非卧床腹膜透析（CAPD）患者根据腹透液肌酐与血肌酐比值（D/Pcr）和Twardoski的评判标准,分为高转运、高平均转运、低平均转运和低转运4组。患者分别使用7.5%艾考糊精透析液或2.5%葡萄糖 Dianeal?誖 PD-2、PD-4透析液,疗程4周。比较各组超滤量。 结果 共201例CAPD患者入选,其中艾考糊精组98例,葡萄糖组103例;男96例,女105例;年龄（56.1±13.7）岁（18～81岁）。198例进行了腹膜平衡试验,其中高转运患者24例（12.1%）,高平均转运72例（36.2%）,低平均转运81例（40.7%）,低转运21例（11.0%）。治疗第4周,高转运、高平均转运和低平均转运患者中,艾考糊精组超滤量显著升高,无论与基线值还是与葡萄糖组比较,差异都有统计学意义;而低转运患者中,艾考糊精组超滤量高于葡萄糖组,但差异无统计学意义。相关分析显示,艾考糊精腹透液产生的超滤量与D/Pcr呈正相关（R2 = 0.1681,P < 0.01）,而葡萄糖透析液产生的超滤量与D/Pcr呈负相关（R2 = 0.0949,P < 0.01）。 结论 7.5%艾考糊精腹透液可显著改善CAPD患者的超滤量和腹膜肌酐清除率,尤其在腹膜高转运、高平均转运和低平均转运患者,其作用显著优于葡萄糖腹透液。     

High peritoneal residual volume decreases the efficiency of peritoneal dialysis

BACKGROUND: Wide variation in peritoneal residual volume (PRV) is a common clinical observation. High PRV has been used in both continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis to minimize the time of a dry peritoneal cavity and to achieve better dialysis. However, the impact of PRV on peritoneal transport is not well established. In this study, we investigated the effect of PRV on peritoneal transport characteristics. METHODS: Peritoneal effluents were collected in 32 male Sprague-Dawley rats after a five-hour dwell with 1.36% glucose solution. Forty-eight hours later, a four hour dwell using 25 ml of 3.86% glucose solution and frequent dialysate and blood sampling was done in each rat with 125I-albumin as a volume marker. Before the infusion of the 3.86% glucose solution, 0 (control), 3, 6, or 12 ml (8 rats in each group) of autologous effluent (serving as PRV) was infused to the peritoneal cavity. RESULTS: After subtracting the PRV, the net ultrafiltration was significantly lower in the PRV groups as compared with the control group: 13.4 +/- 0.5, 12.0 +/- 1.0, 11.7 +/- 1.7, and 8.9 +/- 0.4 ml for 0, 3, 6, and 12 ml PRV groups, respectively (P < 0.001). The lower net ultrafiltration associated with higher PRV was due to (a) a significantly lower transcapillary ultrafiltration rate (Qu) caused by a lower osmotic gradient, and (b) a significantly higher peritoneal fluid absorption rate (KE) caused by an increased intraperitoneal hydrostatic pressure. No significant differences were found in the diffusive mass transport coefficient for small solutes (glucose, urea, sodium, and potassium) and total protein, although the dialysate over plasma concentration ratios values were higher in the high-PRV groups. The sodium removal was significantly lower in the PRV groups as compared with the control group (P < 0.01). CONCLUSION: Our results suggest that a high PRV may decrease net ultrafiltration through decreasing the Qu, which is caused by a decreased dialysate osmolality, and increasing the KE caused by an increased intraperitoneal hydrostatic pressure. The high volume of PRV also decreased the solute diffusion gradient and decreased peritoneal small solute clearances, particularly for sodium. Therefore, a high PRV may compromise the efficiency of dialysis with a glucose solution.     

Diffusive and Convective Solute Transport in Peritoneal Dialysis with Glucose as an Osmotic Agent

Abstract: To investigate possible effects of glucose concentration, dwell time, and peritoneal reabsorption on the combined diffusive and convective peritoneal solute transport, dialysate to plasma concentration ratios (D/P) and solute clearances were evaluated for 6-h peritoneal dwell studies with 1.36, 2.27, and 3.86% glucose solutions. The diffusive mass transport coefficient, K_BD, and sieving coefficient, S, were estimated using the Babb-Randerson-Farrell model of peritoneal transport. Dialysate volumes over time and peritoneal reabsorption rates, K_R, were assessed using radiolabeled iodinated serum albumin (RISA). The transport parameters were estimated with and without peritoneal reabsorption of solutes taken into account. To test the stability of the transport parameters throughout a single peritoneal dwell, K_BD and S values were estimated for the initial 3–120 min, the final 120–360 min, and the entire 3–360 min dwell period for dialysis with 3.86% glucose solution. The transport parameters did not differ between the three dialysis fluids although clearances of small solutes were higher with the 3.86% solution. Values of K_BD, but not S, were dependent on the correction for peritoneal reabsorption of solutes. Computer simulations showed that S could be estimated even with the 1.36% glucose solution. A significant change of the transport parameters, with increased values of K_BD during the initial period of the dwell, was found for urea, potassium, sodium, and total protein during dialysis with the 3.86% solution. S values for urea and potassium were close to 1 during the initial period whereas unphysical (higher than 1) S values were found for the whole dwell period. The transient increase of K_BD during the initial part of the dwell may reflect changes in the peritoneal barrier possibly induced by fresh dialysis fluid. In conclusion, the transport parameters K_BD and S are not influenced by the concentration of glucose in the dialysis fluid. Moreover, the estimation of K_BD but not of 5 is dependent on the assumed rate of peritoneal reabsorption. Finally, the current results challenge the assumption that K_BD and S are constant throughout a peritoneal dialysis exchange.     

Volume stress-induced peritoneal endothelin-1 release in continuous ambulatory peritoneal dialysis

In long-term peritoneal dialysis, functional deterioration of the peritoneal membrane is often associated with proliferative processes of the involved tissues leading to peritoneal fibrosis. In continuous ambulatory peritoneal dialysis (CAPD), failure to achieve target values for adequacy of dialysis is commonly corrected by increasing dwell volume; in case of ultrafiltration failure, osmolarity of the dialysate gets increased. In a prospective study, the impact of increasing dwell volume from 1500 ml to 2500 ml per dwell (volume trial) or changing the osmolarity of the dialysate from 1.36 to 3.86% glucose (hyperosmolarity trial) on the peritoneal endothelin-1 (ET-1) release was analyzed. ET-1 is known to exert significant proliferative activities on a variety of cell types leading to an accumulation of extracellular matrix. A highly significant difference in the cumulative peritoneal ET-1 synthesis was found between the low- and high-volume exchange, whereas differences in the hyperosmolarity setting were only moderate. Sixty minutes after initiating dialysis, the cumulative ET-1 synthesis was 2367 +/- 1023 fmol for the 1500 ml versus 6062 +/- 1419 fmol for the 2500 dwell (P < 0.0001) and 4572 +/- 969 fmol versus 6124 +/- 1473 fmol for the 1.36 and 3.86% glucose dwell (P < 0.05), respectively. In conclusion, increasing dwell volume leads to a strong activation of the peritoneal paracrine endothelin system. Because ET-1, apart from being a potent vasoactive peptide, contributes to fibrotic remodeling, this study indicates that volume stress-induced ET-1 release might contribute to structural alteration of the peritoneal membrane in long-term peritoneal dialysis.     

Dissociation between the Correlation of Peritoneal and Urine Kt/V with Sodium and Fluid Removal: A Possible Explanation of their Difference on Patient Survival

Background: It has been shown that residual renal function but not peritoneal clearance predicted patients’ survival in peritoneal dialysis therapy. In the present study, we tried to explore the potential causes resulting in the difference between residual renal function and peritoneal dialysis in continuous ambulatory peritoneal dialysis (CAPD) patients. Methods: A cross sectional study was performed during July and August 2003 to evaluate the dialysis adequacy in CAPD patients who were clinically stable and had daily urinary volume more than 100 ml. Results: A total of 45 patients (male 27 and female 18) with an average ( ± SD) age of 61.76 ± 13.27 years were included in this study. The daily urinary volume and dialysate ultrafiltration volume were 570.33 ± 395.47 ml and 726.09 ± 454.01 ml, respectively. Peritoneal urea clearance (Kt/V) correlated significantly with the drained daily dialysate volume (r = 0.362, P < 0.01), but not with peritoneal net fluid removal (ultrafiltration) (r = 0.232, P > 0.05) and sodium removal (r = 0.139, P > 0.05). On the other hand, there were strong positive correlations between residual renal Kt/V and daily urine volume (r = 0.802, P < 0.001), as well as between residual renal Kt/V and urinary sodium removal (r = 0.670, P < 0.001). Conclusions: High residual renal Kt/Vurea represents both higher solute clearance and higher sodium and fluid removal, but higher peritoneal Kt/Vurea is not necessarily associated with better sodium and fluid removal. This dissociation might explain the differences on the survival of patients and peritoneal clearances.     

A Model of Ultrafiltration and Glucose Mass Transfer Kinetics in Peritoneal Dialysis

We have investigated the variation with dwell time of dialysate volume and glucose concentration during continuous ambulatory peritoneal dialysis using a one-pool model. No assumption was made regarding the ultrafiltration rate that was calculated by the model. Results show that the volume ultrafiltered during dwell time is an increasing function of peritoneal membrane hydraulic permeability and a decreasing function of glucose mass transfer coefficient (MTC). For large MTC and low initial glucose concentration there is reabsorption of dialysate into the blood at large dwell times. For a 6 h dwell time, glycerol (92 daltons) is a more effective osmotic agent than glucose (198 daltons) at the same weight concentration. These results are in quantitative agreement with published clinical studies.     

Effect of posture on intraperitoneal pressure and peritoneal permeability in children

The posture of the patient influences both the intraperitoneal pressure (IPP) and the peritoneal permeability. We have studied the effects of the supine and the upright position in six children. Two peritoneal equilibration tests (PET) of 90-min dwell time each were performed consecutively, firstly in the supine position and then in the upright position. The same amount of dialysate was instilled (1,000 ml/m²; isotonic 1.36% dextrose) for each PET. Using the same filling volume, the IPP was significantly higher in the upright position (18.4±4.8 cm H₂O) than in the supine position (8±2.4 cm H₂O). The mean percentage IPP increase was 130%±35%. The decline in glucose resorption rate from the dialysate during the PET was significantly lower in the upright position. Despite this greater relative loss of osmotic gradient in the upright than the supine position, no significant difference in net ultrafiltration was noted after 90 min of dwell. The peritoneal equilibration ratio during the PET was lower in the upright than the supine position for urea, creatinine, and phosphate. These results favor performing peritoneal dialysis in a supine position, both to increase dialysis efficiency and to reduce patient discomfort. Received February 18, 1997; received in revised form September 15, 1997; accepted September 22, 1997     

Ultrafiltration failure in continuous ambulatory peritoneal dialysis due to excessive peritoneal cavity lymphatic absorption

We describe a continuous ambulatory peritoneal dialysis (CAPD) patient who developed failure of ultrafiltration for no apparent cause during the first year of treatment. Further investigation showed that peritoneal cavity lymphatic reabsorption during the dwell time exceeded cumulative transcapillary ultrafiltration and so caused negative net ultrafiltration. Peritoneal lymphatic drainage should be added to the list of causes that, either singly or in combination, lead to loss of ultrafiltration in CAPD.     

Pharmacokinetics of once daily intraperitoneal cefazolin in continuous ambulatory peritoneal dialysis patients

This study determined the pharmacokinetic characteristics of once daily intraperitoneal (IP) cefazolin in continuous ambulatory peritoneal dialysis (CAPD) patients. Each of the 10 volunteer CAPD patients without active peritonitis received a single IP dose of 1 g of cefazolin sodium for a 6-h dwell. All patients underwent a fixed CAPD regimen comprising a first 6-h dwell followed by two 3-h dwells and a final 12-h overnight dwell. Blood and dialysate samples were collected at 0, 0.5, 1, 2, 3, 6 (end of first dwell), and 24 h after the administration of IP cefazolin. Any urine produced was collected over the 24-h study period. A validated HPLC method was used to analyze cefazolin in plasma, dialysate, and urine. The bioavailability was found to be 77.9 +/- 3.1%, volume of distribution 0.20 +/- 0.05 L/kg, and plasma half-life 39.9 +/- 25.4 h. Mean total, renal, and peritoneal clearances were 4.5 +/- 2.3, 1. 4 +/- 1.1, and 3.5 +/- 1.8 ml/min, respectively. Mean plasma and dialysate concentrations at 24 h were 42.8 +/- 14.3 and 31.8 +/- 11. 7 mcg/ml, respectively, well above the minimum inhibitory concentrations (MIC) of susceptible organisms. A once daily IP cefazolin dose of 500 mg/L gave desirable pharmacokinetic attributes for use as a suitable alternative to vancomycin for empiric treatment of CAPD-associated peritonitis.     

腹膜透析超滤衰竭的诊治策略

超滤衰竭是腹膜透析常见的并发症,是导致腹膜透析失败的重要原因之一。超滤衰竭定义为4.25%葡萄糖透析液留腹4 h后超滤量<400 ml。超滤衰竭根据病理生理机制分为4种类型：Ⅰ型超滤衰竭由于有效腹膜表面积增加导致,Ⅱ型超滤衰竭由于葡萄糖渗透转导作用下降导致,Ⅲ型超滤衰竭由于腹膜有效表面积减少导致,Ⅳ型超滤衰竭由于通过腹腔淋巴系统或局部组织间隙吸收大量水分导致。避免过度使用高浓度葡萄糖透析液、有效防治腹膜透析相关腹膜炎、保护残肾功能、选用生物相容性好的透析液、使用改善腹膜损伤和纤维化药物等是防治超滤衰竭的有益方法。     

Computer simulations of peritoneal fluid transport in CAPD

To model the changes in intraperitoneal dialysate volume (IPV) occurring over dwell time under various conditions in continuous ambulatory peritoneal dialysis (CAPD), we have, using a personal computer (PC), numerically integrated the phenomenological equations that describe the net ultrafiltration (UF) flow existing across the peritoneal membrane in every moment of a dwell. Computer modelling was performed according to a three-pore model of membrane selectivity as based on current concepts in capillary physiology. This model comprises small "paracellular" pores (radius approximately 47 A) and "large" pores (radius approximately 250 A), together accounting for approximately 98% of the total UF-coefficient (LpS), and also "transcellular" pores (pore radius approximately 4 to 5 A) accounting for 1.5% of LpS. Simulated curves made a good fit to IPV versus time data obtained experimentally in adult patients, using either 1.36 or 3.86% glucose dialysis solutions, under control conditions; when the peritoneal UF-coefficient was set to 0.082 ml/min/mm Hg, the glucose reflection coefficient was 0.043 and the peritoneal lymph flow was set to 0.3 ml/min. Also, theoretical predictions regarding the IPV versus time curves agreed well with the computer simulated results for perturbed values of effective peritoneal surface area, LpS, glucose permeability-surface area product (PS or "MTAC"), intraperitoneal dialysate volume and dialysate glucose concentration. Thus, increasing the peritoneal surface area caused the IPV versus time curves to peak earlier than during control, while the maximal volume ultrafiltered was not markedly affected. However, increasing the glucose PS caused both a reduction in the IPV versus time curve "peak time" and in the "peak height" of the curves. The latter pattern was also seen when the dialysate volume was reduced. It is suggested that computer modelling based on a three-pore model of membrane selectivity may be a useful tool for describing the IPV versus time relationships under various conditions in CAPD.     

Peritoneal sodium mass removal in continuous ambulatory peritoneal dialysis and automated peritoneal dialysis: influence on blood pressure control.

BACKGROUND/AIM: Sodium and water retention is common in peritoneal dialysis patients and contributes to cardiovascular disease. As peritoneal sodium removal depends partly on dwell time, and automated peritoneal dialysis (APD) often uses short dwell time exchanges, the aim of this study was to compare the 24-hour peritoneal sodium removal in APD and standard continuous ambulatory peritoneal dialysis (CAPD) patients and to analyze its possible influence on blood pressure control. METHODS: A total of 53 sodium balance studies (30 in APD and 23 in CAPD) were performed in 36 stable peritoneal dialysis patients. The 24-hour net removal of sodium was calculated as follows: M = ViCi - VdCd, where Vd is the 24-hour drained volume, Cd is the solute sodium concentration in Vd, Vi is the amount of solution used during a 24-hour period, and Ci is the sodium concentration in Vi. Peritoneal sodium removal was compared between APD and CAPD patients. Residual renal function, serum sodium concentration, daily urinary sodium losses, weekly peritoneal Kt/V and creatinine clearance, 4-hour dialysate/plasma creatinine ratio, proportion of hypertonic solutions, net ultrafiltration, systolic and diastolic blood pressures, and need for antihypertensive therapy were also compared between the groups. RESULTS: Peritoneal sodium removal was higher (p < 0.001) in CAPD than in APD patients. There were no significant differences in residual renal function, serum sodium concentration, urinary sodium losses, peritoneal urea or creatinine clearances, 4-hour dialysate/plasma creatinine ratio, or proportion of hypertonic solutions between groups. The net ultrafiltration was higher in CAPD patients and correlated strongly (r = 0.82; p < 0.001) with peritoneal sodium removal. In APD patients, peritoneal sodium removal increased significantly only in those patients with a second daytime exchange. The systolic blood pressure was higher (p < 0.05) in APD patients, and the proportion of patients with antihypertensive therapy was also higher in APD patients, although no significant relationship between blood pressure values and amount of peritoneal sodium removal was found. CONCLUSIONS: The 24-hour sodium removal is higher in CAPD than in APD patients, and there is a trend towards better hypertension control in CAPD patients. As hypertension control and volume status are important indices of peritoneal dialysis adequacy, our results have to be considered in the choice of the peritoneal dialysis modality.     

川芎嗪对慢性腹膜透析大鼠腹膜功能及间皮细胞形态的影响

目的 探讨不同剂量的川芎嗪对高糖透析液作用下慢性大鼠腹膜透析（腹透）模型腹膜间皮细胞的形态和功能的影响及它们之间的关系。方法 ４０只ＳＤ大鼠随机分为４．２５％腹透液（ＨＧ组）、４．２５％腹透液＋４０ｍｇ／Ｌ川芎嗪（ＨＧＬ组）、４．２５％腹透液＋１６０ｍｇ／Ｌ川芎嗪（ＨＧＨ组）、对照组。除对照组外,余３组每天分别腹腔内注入２０ｍｌ含不同剂量川芎嗪的４．２５％透析液［０（ＨＧ）、４０ｍｇ／Ｌ（ＨＧＬ）