Contribution of lymphatic absorption to loss of ultrafiltration and solute clearances in continuous ambulatory peritoneal dialysis.

The contribution of peritoneal cavity lymphatic absorption to ultrafiltration kinetics and solute clearances in continuous ambulatory peritoneal dialysis was evaluated in patients with normal (group 1) and high (group 2) peritoneal permeability X area during 4-h exchanges using 2 liters 2.5% dextrose dialysis solution with 30 g added albumin. Cumulative lymphatic drainage in all continuous ambulatory peritoneal dialysis (CAPD) patients averaged 358 +/- 47 ml per 4-h exchange and reduced cumulative net transcapillary ultrafiltration at the end of the exchange by 58 +/- 7.2%. The peak ultrafiltration volume was observed before osmotic equilibrium between serum and dialysate was reached and occurred when the net transcapillary ultrafiltration rate had decreased to equal the lymphatic absorption rate. Thereafter the lymphatic absorption rate exceeded the net transcapillary ultrafiltration rate, and intraperitoneal volume decreased. Extrapolated to 4 X 2 liters, 2.5% dextrose, 6-h exchanges per d, lymphatic drainage reduced potential daily net ultrafiltration by 83.2 +/- 10.2%, daily urea clearance by 16.9 +/- 1.9%, and daily creatinine clearance by 16.5 +/- 1.9%. Although lymphatic absorption did not differ between the two groups, lymphatic drainage caused a proportionately greater reduction in net ultrafiltration in group 2 (P less than 0.025), because these patients had more rapid dialysate glucose absorption (P less than 0.05) and less cumulative transcapillary ultrafiltration (P less than 0.01). These findings indicate that cumulative lymphatic drainage significantly reduces net ultrafiltration and solute clearances in CAPD and that ultrafiltration failure in CAPD occurs when daily lymphatic absorption equals or exceeds daily transcapillary ultrafiltration. Reduction of lymphatic absorption may provide a means for future improvement in the efficiency of CAPD.     

不同超滤功能的持续不卧床腹膜透析患者腹膜液体转运功能评估

目的 容量控制对于腹膜透析至关重要.腹膜平衡实验(peritoneal equilibration test,PET)可以评估腹膜小分子溶质转动功能,对优化腹膜透析存腹时间提供依据,但是不能预测腹膜液体转运功能.所以,本研究使用计算机拟合对不同超滤功能腹膜透析患者的腹膜液体转运功能进行评估.方法 纳入研究患者包括每天使用3～4袋2.5％葡萄糖透析液者(为腹膜超滤功能差组)和使用3～4袋1.5％葡萄糖透析液者(为腹膜功能好组),两组患者在上述透析处方下都能达到足够的液体清除.所有入组的患者都要求详细记录自己每天的腹膜透析换液情况,以评估腹膜液体转运功能.结果 本研究包括了17名持续不卧床腹膜透析患者(continuous ambulatory peritoneal dialysis,CAPD),其中9名为超滤功能差组,8名为超滤功能好组.与超滤功能好组相比,超滤功能差组的患者每天更多的处于高葡萄糖(P＜0.01)环境中,透析液/血浆肌酐比值(D/Pcre)更高(P＜0.05),有更高的腹膜液体吸收率(Ke)(P＜0.01). 结论 与超滤功能好的患者相比超滤功能差的患者的腹膜小分子溶质转运率更高,更为重要的是,超滤能力差的患者腹膜液体吸收率更高.     

Peritoneal fluid transport in CAPD patients with different transport rates of small solutes.

BACKGROUND: Continuous ambulatory peritoneal dialysis (CAPD) patients with high peritoneal solute transport rate often have inadequate peritoneal fluid transport. It is not known whether this inadequate fluid transport is due solely to a too rapid fall of osmotic pressure, or if the decreased effectiveness of fluid transport is also a contributing factor. OBJECTIVE: To analyze fluid transport parameters and the effectiveness of dialysis fluid osmotic pressure in the induction of fluid flow in CAPD patients with different small solute transport rates. PATIENTS: 44 CAPD patients were placed in low (n = 6), low-average (n = 13), high-average (n = 19), and high (n = 6) transport groups according to a modified peritoneal equilibration test (PET). METHODS: The study involved a 6-hour peritoneal dialysis dwell with 2 L 3.86% glucose dialysis fluid for each patient. Radioisotopically labeled serum albumin was added as a volume marker.The fluid transport parameters (osmotic conductance and fluid absorption rate) were estimated using three mathematical models of fluid transport: (1) Pyle model (model P), which describes ultrafiltration rate as an exponential function of time; (2) model OS, which is based on the linear relationship of ultrafiltration rate and overall osmolality gradient between dialysis fluid and blood; and (3) model G, which is based on the linear relationship between ultrafiltration rate and glucose concentration gradient between dialysis fluid and blood. Diffusive mass transport coefficients (K(BD)) for glucose, urea, creatinine, potassium, and sodium were estimated using the modified Babb-Randerson-Farrell model. RESULTS: The high transport group had significantly lower dialysate volume and glucose and osmolality gradients between dialysate and blood, but significantly higher K(BD) for small solutes compared with the other transport groups. Osmotic conductance, fluid absorption rate, and initial ultrafiltration rate did not differ among the transport groups for model OS and model P. Model G yielded unrealistic values of fluid transport parameters that differed from those estimated by models OS and P. The K(BD) values for small solutes were significantly different among the groups, and did not correlate with fluid transport parameters for model OS. CONCLUSION: The difference in fluid transport between the different transport groups was due only to the differences in the rate of disappearance of the overall osmotic pressure of the dialysate, which was a combined result of the transport rate of glucose and other small solutes. Although the glucose gradient is the major factor influencing ultrafiltration rate, other solutes, such as urea, are also of importance. The counteractive effect of plasma small solutes on transcapillary ultrafiltration was found to be especially notable in low transport patients. Thus, glucose gradient alone should not be considered the only force that shapes the ultrafiltration profile during peritoneal dialysis. We did not find any correlations between diffusive mass transport coefficients for small solutes and fluid transport parameters such as osmotic conductance or fluid and volume marker absorption. We may thus conclude that the pathway(s) for fluid transport appears to be partly independent from the pathway(s) for small solute transport, which supports the hypothesis of different pore types for fluid and solute transport.     

Peritoneal transport in peritoneal dialysis patients using glucose-based and amino acid-based solutions.

OBJECTIVE: To evaluate peritoneal transport of fluid and solutes in continuous ambulatory peritoneal dialysis (CAPD) patients using amino acid (AA)-based versus glucose-based dialysis solutions. METHODS: Using iodine-labeled human serum albumin ((125)I-HSA) as intraperitoneal volume marker, peritoneal transport was investigated in a group of 20 clinically stable patients (11 females and 9 men, age 53 +/- 15 years) on CAPD for 15 - 101 months. Two paired 4-hour dwells, one with 1.36% glucose and one with 1.1% AA dialysis solution, were performed in each patient. Intraperitoneal dialysate volume, fluid absorption rate, and diffusive mass transport coefficients (K(BD)) and sieving coefficients (S) for glucose, creatinine, urea, potassium, and total protein were estimated for each dwell study. Dwell studies with AA solution were used to estimate K(BD) values for individual AAs. RESULTS: Intraperitoneal dialysate volume was higher for AA solution in comparison with glucose solution due to the higher osmolality of the AA solution. No statistically significant difference was found for K(BD) or S for creatinine, urea, potassium, or total protein in the dwell studies with either solution, whereas K(BD) for glucose was higher with AA than with glucose solution. Mean values of K(BD) of AA were similar but with high standard deviation, reflecting inter-individual variations in peritoneal transport rate. CONCLUSION: Our results indicate that the AA peritoneal transport rate is strongly dependent on transport characteristics of the individual peritoneal membrane.     

Changes in water transport across the peritoneum during treatment with continuous ambulatory peritoneal dialysis in selected patients with and without peritonitis.

BACKGROUND: The natural course of longitudinal changes in peritoneal permeability and membrane area has been studied mostly by performing single-dwell studies in selected patients during treatment with peritoneal dialysis. PURPOSE: To evaluate the permeability characteristics of the peritoneal membrane by measuring drained ultrafiltration volume relative to initial glucose concentration in dialysis fluid from the start to the end of continuous ambulatory peritoneal dialysis (CAPD) treatment in a selected cohort of patients with and without peritonitis. DESIGN: A retrospective analysis of a group of patients whose peritoneal function was prospectively followed by recording drained ultrafiltration volume and glucose concentration in dialysis fluid for each dwell time, every day, during the time in CAPD treatment. Mean values from a 1-month period starting after the first 3 weeks of CAPD treatment were compared with the mean values from the last month of treatment. Approximately 11 500 exchanges were analyzed. Evaluations were done separately for short (day) and long (night) dwell times. PATIENTS AND STATISTICS: Of 132 patients commencing CAPD treatment in the time period selected for inclusion, 51 had enough data to be included in this study. Of these, 29 patients experienced one or more episodes of successfully treated peritonitis. The selection of patients was not based upon patient characteristics, but upon criteria to satisfy predefined demands, such as number of measurements in each period, time since an episode of peritonitis, and time on CAPD treatment. Data were analyzed in three different groups: patients with episodes of peritonitis, patients without peritonitis, and both groups together. To assess changes between monthly mean at the start and at the end of CAPD, paired t-test was performed. Patients were also stratified into two groups according to low and high glucose in dialysis fluid at the start of CAPD (cutoff = 2 g/dL). Additionally, we used linear regression analyses to predict the level of drained ultrafiltration volume for a given level and change in glucose concentration. Mean treatment time for the entire group was 20 months (median 14.3 months), ranging from 6 to 69 months. RESULTS: No statistical differences in glucose concentrations were found between the periods compared. In the entire group there was an increase in ultrafiltration volume from the start to the end of CAPD treatment, for both day (p = 0.009) and night (p = 0.013) exchanges. Also, for patients without peritonitis, an increase appeared for day (p = 0.046) and night exchanges (p = 0.053). However, for the cohort with peritonitis, only an insignificant increase was indicated. Patient characteristics, diabetic patients, the need for glucose in dialysis fluid when commencing CAPD treatment, the number of episodes of peritonitis, and time on CAPD did not influence the change in ultrafiltration. Regression analyses showed higher ultrafiltration response to a given level and change in glucose concentration at the end of CAPD treatment compared to the start values, also for the cohort with peritonitis. The regression coefficient between these variables was also significantly changed for both day (p < 0.0001) and night (p = 0.027) exchanges. CONCLUSION: A significant change in the regression coefficient between glucose in dialysis fluid and ultrafiltration volume reflects an increase in ultrafiltration response to a given level and change in glucose concentration during time on CAPD treatment. A parallel change after 5- and 9-hour dwells can be explained by a decrease in peritoneal surface area combined with a lesser decrease in peritoneal conductivity. However, changes in Starling forces across the peritoneal membrane are possible even in the absence of changes in peritoneal membrane characteristics.     

Intraperitoneal administration of phosphatidylcholine improves ultrafiltration in continuous ambulatory peritoneal dialysis patients.

Reports in the literature have linked a low phosphatidylcholine content in continuous ambulatory peritoneal dialysis (CAPD) effluent to ultrafiltration loss. Clinical evidence suggests that adding phosphatidylcholine to the dialysis solution enhances ultrafiltration. A clinical study has been designed to clarify the effect of phosphatidylcholine on ultrafiltration in CAPD patients with normal ultrafiltration. A weekly measurement of the peritoneal equilibration test was conducted per patient in the hospital. A comparison between the control dialysis solution (three-week period) and the phosphatidylcholine premixed solution (three-week period) was performed on a total of 12 patients. This study shows that a phosphatidylcholine premixed dialysis solution significantly enhances ultrafiltration. Since ultrafiltration per osmotic driving force (mL/g glucose) is enhanced, the patient's glucose load per day is reduced to achieve equal ultrafiltration. In the presence of phosphatidylcholine, peritoneal permeability remained unchanged, as indicated by membrane transport characteristics. No side effects were observed.     

Physiology of the peritoneum. Implications for peritoneal dialysis

Solute and water transport from blood to peritoneal cavity occur by diffusion and osmotic ultrafiltration, whereas absorption to blood via lymphatics negatively affects these two processes. This article delineates the physiology of peritoneal membrane and numerous factors that influence mass transport during peritoneal dialysis, thereby affecting its therapeutic efficacy. Benefits and limitations of continuous ambulatory peritoneal dialysis (CAPD) are discussed and compared to those of hemodialysis. Survival on CAPD, its complications and imperfections are reviewed in light of the widespread acceptance of the procedure.     

Hyaluronan preserves peritoneal membrane transport properties.

BACKGROUND: We have shown that intraperitoneal (i.p.) addition of hyaluronan (HA) in a single dwell study in rat could increase peritoneal fluid removal by decreasing the peritoneal fluid absorption rate. In this study, we investigated the impact of repeated use of HA on peritoneal membrane transport characteristics. METHODS: Twelve male Sprague-Dawley rats received a once-daily i.p. injection of 25 mL 4.25% glucose dialysis solution without (HP group, n = 6) or with 0.025% HA (HA group, n = 6) for 1 week. Forty-eight hours after the last injection, a 4-hour dwell using 25 mL 4.25% glucose dialysis solution with i.p. volume marker and frequent dialysate and blood samplings was performed in each rat as well as in rats that did not receive any injection (control group, n = 8). RESULTS: Although the i.p. volumes were significantly lower in the HP and HA groups compared to the control group, i.p. volume in the HA group was significantly higher than in the HP group. Net ultrafiltration at 4 hours was 5.6 +/- 1.3 mL, 10.2 +/- 1.8 mL, and 13.2 +/- 0.6 mL for the HP, HA, and control group, respectively. The peritoneal fluid absorption rate decreased by 45% in the HA group compared to the HP group. There was no significant difference in peritoneal fluid absorption rate between the HA and the control group. No difference was found in the direct lymphatic absorption rate between the HP and HA groups [0.010 +/- 0.003 mL/minute in the HP group and 0.011 +/- 0.004 mL/min in the HA group] although they were both higher than that of the control group (0.004 +/- 0.001 mL/min).The solute transport rates were in general significantly higher in the HP group compared to the HA and control groups, and there was no significant difference between the latter two groups, except that protein transport rate was significantly lower in the HA group compared to the control group. CONCLUSIONS: The present study suggests that (1) repeated exposure to hypertonic glucose-based dialysis solution results in increased peritoneal solute transport rates, as well as increased peritoneal fluid absorption rates; and (2) these changes, reflecting a highly permeable peritoneal membrane, were ameliorated by repeated i.p. addition of hyaluronan. The similar changes in the direct lymphatic absorption rate in rats that received daily i.p. injection of dialysis solution suggest that direct peritoneal lymphatic absorption was not influenced by hyaluronan.     

Peritoneal accumulation of AGE and peritoneal membrane permeability.

BACKGROUND: In continuous ambulatory peritoneal dialysis (CAPD), the peritoneal membrane is continuously exposed to high-glucose-containing dialysis solutions. Abnormally high glucose concentration in the peritoneal cavity may enhance advanced glycosylation end-product (AGE) formation and accumulation in the peritoneum. Increased AGE accumulation in the peritoneum, decreased ultrafiltration volume, and increased peritoneal permeability in long-term dialysis patients have been reported. AIM: The purpose of the study was to evaluate the relation between peritoneal membrane permeability and peritoneal accumulation of AGE. METHODS: Peritoneal membrane permeability was evaluated by peritoneal equilibration test (PET) using dialysis solutions containing 4.25% glucose. Serum, dialysate, and peritoneal tissue levels of AGE were measured by ELISA method using polyclonal anti-AGE antibody. Peritoneal biopsy was performed during peritoneal catheter insertion [new group (group N), n = 18] and removal [long-term group (group LT), n = 10]. Peritoneal catheters were removed due to exit-site infection not extended into the internal cuff (n = 6) and ultrafiltration failure (n = 4) after 51.6+/-31.5 months (13 - 101 months) of dialysis. PET data obtained within 3 months after the initiation of CAPD or before catheter removal were included in this study. Ten patients in group N and 4 patients in group LT were diabetic. Patients in group LT were significantly younger (46.5+/-11.1 years vs 57.5+/-1.3 years) and experienced more episodes of peritonitis (3.5+/-2.1 vs 0.2+/-0.7) than group N. RESULTS: Peritoneal tissue AGE level in group LT was significantly higher than in group N, in both nondiabetic (0.187+/-0.108 U/mg vs 0.093+/-0.08 U/mg of hydroxyproline, p < 0.03) and diabetic patients (0.384+/-0.035 U/mg vs 0.152+/-0.082 U/mg of hydroxyproline, p < 0.03), while serum and dialysate levels did not differ between the groups in both nondiabetic and diabetic patients. Drain volume (2600+/-237 mL vs 2766+/-222 mL, p = 0.07) and D4/D0 glucose (0.229+/-0.066 vs 0.298+/-0.081, p < 0.009) were lower, and D4/P4 creatinine (0.807+/-0.100 vs 0.653+/-0.144, p< 0.0001) and D1/P1 sodium (0.886+/-0.040 vs 0.822+/-0.032, p < 0.0003) were significantly higher in group LT than in group N. On linear regression analysis, AGE level in the peritoneum was directly correlated with duration of CAPD (r = 0.476, p = 0.012), number of peritonitis episodes (r = 0.433, p = 0.0215), D4/P4 creatinine (r = 0.546, p < 0.027), and D1/P1 sodium (r = 0.422, p = 0.0254), and inversely correlated with drain volume (r = 0.432, p = 0.022) and D4/D0 glucose (r = 0.552, p < 0.0023). AGE level in the peritoneal tissue and dialysate were significantly higher in diabetics than in nondiabetics in group LT, while these differences were not found in group N. Serum AGE level did not differ between nondiabetics and diabetics in either group N or group LT. Drain volume and D4/D0 glucose were lower and D4/P4 creatinine and D1/P1 sodium higher in diabetics than in nondiabetics in both groups. CONCLUSION: Peritoneal accumulation of AGE increased with time on CAPD and number of peritonitis episodes, and was directly related with peritoneal permeability. Peritoneal AGE accumulation and peritoneal permeability in diabetic patients were higher than in nondiabetic patients from the beginning of CAPD.     

多巴胺在低腹膜转运患者中的运用

目的：寻找提高低腹膜转运功能患者的腹膜透析效能方法,使之达到或接近充分透析的指标。方法：先测定腹膜透析患者的腹膜转运功能,对低转运功能或低于平均转运功能的患者在其腹透液中加入小剂量多巴胺（５ｍｇ∶２Ｌ腹透液）,然后观察其腹膜转运功能的变化,并通过动物实验得到证实。结果：５７例腹膜透析患者中,低转运功能和低于平均转运功能的患者共１８例,其中１２例低于平均转运功能患者加入多巴胺后,腹膜对肌酐（Ｃｒ）的转运效率提高了１２．０％,而蛋白质的丢失同时增加２３．６％。动物实验重复了上述结果。结论：腹透液中加入小剂量多巴胺后可以提高腹膜对物质的转运功能。推测可能是通过扩张腹膜内毛细血管,增加了腹膜交换面积所致。     

Fluid and solute transport using different sodium concentrations in peritoneal dialysis solutions.

BACKGROUND: Fluid and sodium balance is important for the success of long-term peritoneal dialysis. Convective transport is the major determinant for sodium removal during peritoneal dialysis using conventional dialysis solutions. However, recent studies showed that lower sodium concentration in dialysate could significantly increase sodium removal by increasing the diffusion gradient, thereby increasing diffusive transport. In the present study, we investigated the influence of the sodium concentration gradient on the diffusive transport coefficient, K(BD) for sodium. METHODS: A 4-hour dwell study was done in Sprague-Dawley rats using 25 mL 5% glucose (NS), 5% glucose + 0.3% NaCl (LS), 5% glucose + 0.6% NaCl (MS), or 5% glucose + 0.9% NaCl (HS), with frequent dialysate and blood sampling. Radiolabeled human albumin (RISA) was added to the solution as an intraperitoneal volume marker. The peritoneal fluid and sodium transport characteristics were evaluated. RESULTS: Significant ultrafiltration (both net ultrafiltration and transcapillary ultrafiltration) was observed in each group despite the osmolality of the 5% glucose solution being slightly lower than the plasma osmolality. There was no difference in peritoneal fluid absorption rate and direct lymphatic absorption among the four groups. With the sieving coefficient for sodium set to 0.55, a significantly higher K(BD) for sodium was found in the NS compared to the HS group. The K(BD) for sodium was 0.21+/-0.01, 0.20+/-0.01, 0.17+/-0.01, and 0.09+/-0.01 mL/min for the NS, LS, MS, and HS groups, respectively. The K(BD) values for glucose were significantly lower in the NS and LS groups compared to the MS and HS groups. CONCLUSIONS: Our results suggest that (1) sodium concentration may affect peritoneal sodium K(BD)--as the sodium concentration gradient increased, the K(BD) decreased; (2) 5% glucose solution could induce significant peritoneal ultrafiltration in normal rats despite its initial hypo-osmotic nature, this was due to the significantly lower glucose transport rate than sodium transport rate; and (3) a lower dialysate sodium concentration may decrease peritoneal glucose absorption.     

容量控制对腹膜透析患者体液平衡的影响

目的探讨容量负荷控制对持续性腹膜透析(CAPD)患者体液平衡的影响。方法选择山东中医药大学第二附属医院肾内科CAPD治疗患者32例,限制水盐摄入1-3个月,测定限制水盐前后体重、平均动脉压、超滤量、下腔静脉直径(IVCD)等相关指标。结果CAPD患者限制水盐后水肿程度、体重、平均动脉压、透析液糖浓度、透析液糖总量、透析液总剂量、每日平均超滤量及总液体清除量与限制水盐以前比较明显降低,P<0．05差异有显著性。IVCD与收缩压值有直线相关关系(r前=0．407,P<0．01;r后=0．413,P<0．01)。限制水盐前后患者的尿量无明显变化,P>0．05。结论严格限制腹膜透析患者水钠摄入,可降低容量负荷,从而降低血压、减轻水肿,改善患者的一般状况;下腔静脉直径能精确评估体液负荷状况。     

Dialysis efficiency in continuous ambulatory peritoneal dialysis patients treated with erythropoietin.

OBJECTIVE: To determine the effect of subcutaneous erythropoietin treatment on dialysis efficiency in continuous ambulatory peritoneal dialysis (CAPD) patients. DESIGN: Dialysis efficiency, platelet and white cell aggregation, and red cell deformability were measured monthly for six months in nine anaemic CAPD patients treated with erythropoietin, and on a single occasion in seven control CAPD patients with intrinsically high haemoglobin concentrations. SETTING: Renal dialysis unit. PATIENTS: Nine patients stable on CAPD for a minimum of six months and with haemoglobin concentrations less than 8.5 g/dl were treated with erythropoietin. Seven CAPD patients matched for age and renal function, with haemoglobins greater than 9.0 g/dl served as controls. RESULTS: Daily peritoneal clearances and net ultrafiltration volumes were unchanged when haematocrit increased from 25.0 +/- 2.2% to 36.5 +/- 3.5%. Spontaneous whole blood platelet aggregation was significantly increased from week twelve (pre-treatment aggregation 46 +/- 23%; 12 weeks: 67 +/- 19%, p less than 0.05; 16 weeks: 64 +/- 19%, p less than 0.01; 20 weeks: 71 +/- 16%, p less than 0.01; 24 weeks: 73 +/- 10%, p less than 0.01). CONCLUSIONS: The increase in haematocrit and platelet aggregation associated with erythropoietin treatment did not affect peritoneal clearances or ultrafiltration capacity.     

The association of peritoneal transport properties with 24-hour blood pressure levels in CAPD patients.

OBJECTIVES: We aimed to investigate the effects of peritoneal transport characteristics on blood pressure (BP) parameters, measured by 24-hour ambulatory blood pressure monitoring (ABPM), and on the development of left ventricular hypertrophy (LVH) in continuous ambulatory peritoneal dialysis (CAPD) patients. DESIGN: Cross-sectional and prospective design. SETTING: Tertiary-care center. PATIENTS: 25 CAPD patients (11 male, 14 female; mean age 47 +/- 14 years) were included. Mean time on CAPD was 22.9 +/- 18 months and all patients had been dialyzed for more than 6 months. The patients were divided into high, high-average, low-average, and low transport groups according to peritoneal equilibration test results. MAIN OUTCOME MEASURES: Daytime and nighttime systolic and diastolic BP and left ventricular mass index among the different peritoneal transport groups; changes in BP parameters before and after increase in ultrafiltration. RESULTS: On 24-hour ABPM records, 13 patients (52%) were found to be hypertensive. Both mean systolic and diastolic BP were significantly increased in high-transporter groups compared to low transporters in both daytime and nighttime BP parameters. Left ventricular mass index was higher in high transporters compared to low transporters, without reaching statistical significance: 160 +/- 23 vs 119 +/- 41 g/m2, p > 0.05. Following increase in ultrafiltration, mean systolic (145 +/- 13 vs 128 +/- 5 mmHg, p < 0.001) and diastolic (96 +/- 10 vs 81 +/- 3 mmHg, p < 0.001) BP decreased, and BP levels returned to normotensive levels in 6 (46%) of the 13 hypertensive patients, requiring discontinuation of antihypertensive drugs. CONCLUSION: Improvement in volume status resulted in a decrease in both daytime and nighttime BP. Differences in peritoneal transport properties were associated with the development of hypertension and LVH.     

Serum BNP concentration and left ventricular mass in CAPD and automated peritoneal dialysis patients.

OBJECTIVE: To compare ultrafiltration under continuous ambulatory peritoneal dialysis (CAPD) and automated PD (APD), disclosing potential effects on serum B-type natriuretic peptide (BNP) levels and echocardiographic findings. PATIENTS AND METHODS: This cross-sectional clinical study included 32 patients on CAPD and 30 patients on APD without clinical evidence of heart failure or hemodynamically significant valvular heart disease. Peritoneal equilibration tests, BNP levels, and echocardiographic measurements were performed in each subject. BNP measurements were also performed in 24 healthy control subjects. RESULTS: Patients on APD had lower ultrafiltration and higher values of BNP and left ventricular mass index (LVMI) compared with patients on CAPD (respectively: 775 +/- 160 vs 850 +/- 265 mL, p = 0.01; 253.23 +/- 81.64 vs 109.42 +/- 25.63 pg/mL, p = 0.001; 185.12 +/- 63.50 vs 129.30 +/- 40.95 g/m(2), p = 0.001). This occurred despite higher mean dialysate glucose concentrations and far more extensive use of icodextrin in the APD group. CONCLUSION: Treatment with APD is associated with higher plasma BNP levels and LVMI compared to CAPD. This may be the result of chronic fluid retention caused by lower ultrafiltration in APD patients.     

Oral neostigmine and lymphatic absorption in a myasthenia gravis patient on continuous ambulatory peritoneal dialysis (CAPD)

The effects of oral neostigmine on peritoneal lymph absorption and transcapillary and net ultrafiltration were studied in a myasthenia gravis patient on continuous ambulatory peritoneal dialysis (CAPD). Oral neostigmine decreased lymphatic absorption, but only up to a threshold dose. The effect on net ultrafiltration however was nullified to some extent by a concurrent decrease in cumulative transcapillary ultrafiltration.     

Twenty-four hour hormonal and metabolic profiles in uraemic patients before and during treatment with continuous ambulatory peritoneal dialysis

Circulating intermediary metabolite and hormone concentrations were measured at intervals over 24 h in five uraemic patients before starting dialysis and after 3 months' treatment with continuous ambulatory peritoneal dialysis (CAPD) and in 13 non-uraemic normal controls. Fasting and postprandial glucose concentrations were significantly raised in uraemic patients undialysed and on CAPD but 24 h mean (+/- SEM) levels fell from 6.63 +/- 0.40 to 6.00 +/- 0.26 mmol/l (P less than 0.02) after 3 months' dialysis despite peritoneal glucose absorption. Insulin levels were raised in uraemic patients but were unchanged by CAPD. Uraemia was associated with raised levels of the gluconeogenic precursors lactate and alanine and a further rise in fasting and 24 h mean alanine concentrations occurred with CAPD. Fasting total ketone body concentrations were raised in undialysed uraemic patients but concentrations were suppressed throughout the 24 h in CAPD subjects. Fasting triglyceride concentrations were increased in uraemic subjects and mean 24 h levels rose by 30% from 1.55 +/- 0.42 mmol/l before dialysis to 2.02 +/- 0.59 mmol/l during CAPD. Non-esterified fatty acid concentrations were low in uraemic patients and remained low during CAPD. Undialysed and dialysed uraemic patients displayed raised plasma glucagon concentrations throughout the 24 h, suppression of the normal nocturnal secretion of growth hormone and raised mean cortisol levels, which were 23% (CAPD) to 57% (undialysed) higher than in normal controls. The endocrine and metabolic abnormalities of uraemia are not fully corrected by CAPD. Many of the additional changes observed during CAPD reflect an adaptation to the constant absorption of peritoneal glucose.     

CAPD患者腹膜转运功能对患者生存率的影响

目的 了解腹膜透析开始时腹膜转运类型对连续非卧床腹膜透析（CAPD）患者生存率的影响. 方法 选择首都医科大学附属北京友谊医院透析时间大于3个月,且在开始腹膜透析的头3个月内接受了腹膜平衡试验（PET）的患者94名,并根据PET结果分为高转运（H）、高平均（HA）、低平均（LA）和低转运（L）4组,分析各组间残余肾功能、腹膜透析持续时间、腹膜透析对小分子溶质清除情况以及腹膜透析超滤情况的差异. 结果 在四组之间,残余肾功能差异没有显著性;在转运功能强的患者中总肌酐清除率较高,但腹膜透析超滤则低于转运功能弱的患者（P值均小于0.05）.在4组患者中,Kaplan-Meier法生存率分析显示累积生存率差异存在着显著性（χ^2=9.24,P=0.0262）;且高转运和高平均组患者的生存率显著低于低平均组患者（P值分别为0.0026和0.0031）. 结论 腹膜转运功能强的CAPD患者,生存率低于转运功能弱的患者.这无法用小分子溶质的清除效率来解释,可能与转运功能弱的患者腹膜透析超滤效果较好有关.     

Loss of ultrafiltration in continuous ambulatory peritoneal dialysis (CAPD)

Fifteen patients on long-term continuous ambulatory peritoneal dialysis (CAPD) were assessed with respect to net ultrafiltration capacity. Eight patients were defined as having good and seven as having poor ultrafiltration on the basis of net ultrafiltrate obtained/mmol glucose infused. Subsequently, dialysate was sampled at times 0, 1, 15, 30, 60, 90, 120, 180, and 240 min. No difference in residual volume was observed between the groups. A significantly greater decrease in dialysate sodium during the initial dialysis period in those patients with good as compared to those with poor ultrafiltration occurred, reflecting a greater transcapillary movement of electrolyte poor ultrafiltrate. In those with good ultrafiltration, glucose transfer was normal in five and rapid in three, suggesting the latter had low rates of lymphatic reabsorption. Five of seven patients with poor ultrafiltration had no fall in dialysate sodium in association with a high rate of glucose transfer, suggesting a low rate of transcapillary water movement and normal to high lymphatic absorption. Two patients with low ultrafiltration had an initial fall in dialysate sodium with a normal glucose transfer and thus net ultrafiltration is low due to elevated lymphatic reabsorption. We thus propose that the relative contribution of transcapillary water movement and lymphatic reabsorption can be determined by assessing net ultrafiltration and dialysate sodium concentration in conjunction with solute transfer.     

Phosphatidylcholine administration in continuous ambulatory peritoneal dialysis (CAPD) patients with reduced ultrafiltration

To evaluate the possible role of oral phosphatidylcholine administration in improving peritoneal ultrafiltration sixteen continuous ambulatory peritoneal dialysis (CAPD) patients with a reduced ultrafiltration rate (less than 500 mL/4 h after a standard 3.86% glucose exchange) were studied. Three patients spontaneously stopped phosphatidylcholine due to gastric side effects. Three out of the remaining 13 patients showed a mild increase of standard ultrafiltration, which was not followed by any increase in daily dialysate output. No differences in glucose, sodium, potassium, urea and creatinine equilibration curves were seen. In conclusion, in our series oral phosphatidylcholine is not free of side effects, and its efficacy in improving ultrafiltration is scanty, with no clinical relevance in increasing daily ultrafiltration.