Gastric emptying in patients with chronic renal failure on continuous ambulatory peritoneal dialysis

Radionuclide gastric emptying studies were carried out on 20patients with end-stage renal failure (ESRF) undergoing continuousambulatory peritoneal dialysis (CAPD). Nine of the patientshad diabetes mellitus. Eight normal volunteers were also studiedto establish normal ranges. Solid and liquid emptying patternswere investigated simultaneously using a meal made up of a solidphase labelled with ^99mTechnetium and a liquid phase labelledwith ¹¹¹Indium. The solid emptying fitted a model with a lagphase followed by a linear emptying phase and the liquid emptyingfitted a single exponential. Nine of the 20 patients (four diabetic,five non-diabetic) were found to have delayed solid emptying,and four of these (two diabetic, two non-diabetic) also haddelayed liquid emptying. No correlation was found between anyof the parameters studied and the clinical symptoms of the patients.It is concluded that almost half of the patients studied hadabnormal gastric emptying, but that many of these did not sufferfrom severe symptoms.     

Effect of intraperitoneal fluid volume changes on esophageal pressures: studies in patients on continuous ambulatory peritoneal dialysis

Esophageal manometric studies were performed in 11 patients on continuous ambulatory peritoneal dialysis (CAPD) with the dialysis fluid in the peritoneal cavity, after emptying and again after reinfusion. No systematic changes were found in intragastric or lower esophageal sphincter (LES) pressures at any time. No differences in mean distal esophageal amplitude (DEA), duration, or velocity of peristalsis were noted. Although upper gastrointestinal problems are common in CAPD patients and were reported by eight of 11 patients, this study suggests that these symptoms cannot be explained by changes in gastric and esophageal pressures.     

Plasma and dialysate immunoglobulin G in continuous ambulatory peritoneal dialysis patients: a multicenter study

Peritoneal dialysate immunoglobulin (Ig)G concentrations were measured in 120 continuous ambulatory peritoneal dialysis (CAPD) patients evaluated at four dialysis centers in different countries to assess the normal range for dialysate IgG and to investigate the relationships of this protein levels with peritoneal episodes, For 65 of these patients, plasma IgG levels were determined, and IgG clearances were calculated. The mean dialysate concentration of IgG was 6.9 +/- 4.2 mg/dl, and there was no difference between men and women or between patients who had or had not previously undergone hemodialysis. Dialysate IgG concentrations were significantly related to residual renal creatinine clearance and negatively correlated with dialysate volume, plasma albumin and total protein. There were no significant correlations between IgG levels in the dialysate and age, protein losses in the dialysate, time on CAPD or time from the last peritonitis episode. Plasma and dialysate IgG were unrelated to the incidence of peritonitis, statistical analysis being performed with different methods. These results suggest that IgG levels in the dialysate or plasma are not a major factor in the prevention of CAPD peritonitis.     

Gastric emptying in patients on renal replacement therapy

In addition to gastrointestinal tract symptoms such as nausea, vomiting, and loss of appetite, impaired gastric emptying time (GET) may be related to nutritional parameters and nutritional status of patients on renal replacement therapy (RRT). Patients on RRT are affected by several factors such as uremic toxins, the presence of dialysate in the peritoneal cavity, and the drugs used against renal allograft rejection. In this study, we investigated the gastric emptying time and its relationship with biochemical and nutritional parameters in patients on RRT: those on hemodialysis and peritoneal dialysis, and renal transplantation patients. Seventy-five patients, 44 on hemodialysis, 16 on peritoneal dialysis, and 15 renal transplant patients, were included in the study. They were examined for gastric emptying time using a radioisotopic method. The results were compared with the GET of healthy subjects. Each group of patients was evaluated in terms of hemoglobin, hematocrit, blood urea nitrogen (BUN), creatinine, blood glucose, total protein, albumin, serum lipids, parathyroid hormone (PTH) and body mass index and biceps and triceps skinfold. The mean GET of patients on RRT was significantly longer than the mean GET of healthy subjects (87.8 +/- 23.4 vs. 55 +/- 18 min, p<0.05). The mean GET of each therapy subgroups was significantly longer than the healthy subjects (the mean GET was 85.1 +/- 22.4 min for hemodialysis, 87.7+/-31.8 min for peritoneal dialysis, and 94.6+/-16.7 min for renal transplant patients, respectively, p<0.05). On the other hand, the differences in the mean GET between the three therapy subgroups were not statistically significant (p>0.05). In addition, time on replacement therapy inversely and blood glucose positively correlated with GET in renal transplant patients. In conclusion, GET was longer in patients on all three RRT modalities than in healthy subjects. GET was not significantly different in dialysis patients and renal transplant patients.     

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.     

Serum concentration and peritoneal transfer of aluminum during treatment by continuous ambulatory peritoneal dialysis

The evolution of the aluminum (A1) serum levels during a 2-year follow-up and the peritoneal transfer of A1 were studied in 22 patients treated by continuous ambulatory peritoneal dialysis (CAPD), using a dialysate with a very low A1 concentration (r = 0.25 - 0.30 mumoles/liter). Patients were divided in three groups. A transfer of A1 from the patient to the dialysate was observed in all patients. In group 1, patients exclusively treated by CAPD and who have never received aluminum-containing phosphate binders (ACPB), mean level (+/- SD) of serum A1 stabilized within a safe range (0.60 +/- 0.28 mumoles/liter). In group 2 the oral administration of ACPB in patients exclusively treated by CAPD induced a slow and progressive increase of A1 serum concentration despite the increase of the A1 excretion through the peritoneal route. In group 3, patients previously treated by hemodialysis and receiving ACPB, the high serum A1 levels observed before treatment by CAPD decreased rapidly on CAPD. A1 removal through the peritoneum was higher in group 3 than in group 2 despite serum A1 levels not statistically different in both groups. A1 removal through the peritoneum is mainly influenced by serum and dialysate A1 concentration. A1 body stores could play a role in the transfer of A1 through the peritoneum. Three cases of A1 poisoning due to the accidental use of a dialysate with a high A1 content are reported.     

Gastric Emptying in Patients on Renal Replacement Therapy

In addition to gastrointestinal tract symptoms such as nausea, vomiting, and loss of appetite, impaired gastric emptying time (GET) may be related to nutritional parameters and nutritional status of patients on renal replacement therapy (RRT). Patients on RRT are affected by several factors such as uremic toxins, the presence of dialysate in the peritoneal cavity, and the drugs used against renal allograft rejection. In this study, we investigated the gastric emptying time and its relationship with biochemical and nutritional parameters in patients on RRT: those on hemodialysis and peritoneal dialysis, and renal transplantation patients. Seventy‐five patients, 44 on hemodialysis, 16 on peritoneal dialysis, and 15 renal transplant patients, were included in the study. They were examined for gastric emptying time using a radioisotopic method. The results were compared with the GET of healthy subjects. Each group of patients was evaluated in terms of hemoglobin, hematocrit, blood urea nitrogen (BUN), creatinine, blood glucose, total protein, albumin, serum lipids, parathyroid hormone (PTH) and body mass index and biceps and triceps skinfold. The mean GET of patients on RRT was significantly longer than the mean GET of healthy subjects (87.8 ± 23.4 vs. 55 ± 18 min, p < 0.05). The mean GET of each therapy subgroups was significantly longer than the healthy subjects (the mean GET was 85.1 ± 22.4 min for hemodialysis, 87.7 ± 31.8 min for peritoneal dialysis, and 94.6 ± 16.7 min for renal transplant patients, respectively, p < 0.05). On the other hand, the differences in the mean GET between the three therapy subgroups were not statistically significant (p > 0.05). In addition, time on replacement therapy inversely and blood glucose positively correlated with GET in renal transplant patients. In conclusion, GET was longer in patients on all three RRT modalities than in healthy subjects. GET was not significantly different in dialysis patients and renal transplant patients.     

持续非卧床腹膜透析患者血清肌酐水平的影响因素分析

目的：探讨影响持续非卧床腹膜透析（CAPD）患者血清肌酐水平的因素。方法：选取北京大学第三医院腹透中心200名临床情况稳定的CAPD患者为研究对象。同时收集患者人口学特征、血清肌酐（Scr）及其他生化资料,评估腹膜透析充分性,采用简单相关及多元回归分析探讨影响Scr水平的因素。结果：所有患者平均年龄（61.02±14.81）岁,平均Scr（893±293）μmol/L;简单相关分析显示Scr水平与年龄、总尿素清除指数（TKt/V）、残肾尿素清除指数（RKt/V）、总肌酐清除率（Tccr）及残肾肌酐清除率（Rccr）呈负相关,而与透析剂量、体质指数（BMI）、透析龄呈正相关,差异均具有统计学意义;逐步多元回归分析提示在矫正透析剂量、透析龄及糖尿病等因素后,性别、年龄、Tccr、RKt/V、透析液肌酐浓度/血肌酐浓度（D/PCr）及BMI是影响Scr水平的独立因素（R2=0.659,P〈0.05）。结论：本研究提示在剂量、透析龄及糖尿病等因素后,性别、年龄、营养状况、残余肾功能及腹膜转运功能仍能独立地影响CAPD患者血清肌酐水平。     

Intraperitoneal production of erythropoietin with continuous ambulatory peritoneal dialysis

Higher hematocrit and serum erythropoietin (EPO) levels have previously been shown in end-stage renal disease patients treated with continuous ambulatory peritoneal dialysis (CAPD) compared with hemodialysis. We investigated whether EPO was produced intraperitoneally in CAPD patients. EPO concentration was 3.5±0.3 mU/ml by radioimmunoassay in 26 samples of peritoneal dialysis effluent obtained from 15 CAPD patients. EPO was not detectable in the fresh unused dialysate. No correlation was observed between EPO levels in the serum and dialysis effluent. Peritoneal macrophages were isolated from the dialysis effluent of 9 CAPD patients after an overnight dwell. The culture supernatant obtained after 24 h of in vitro culture of a million cells yielded EPO of 3.5±0.3 mU/ml. Our study demonstrated that peritoneal macrophages from CAPD patients produce EPO on in vitro stimulation, and EPO is present in the dialysis effluent of CAPD patients.     

腹膜溶质转运特性对腹膜透析患者营养指标的影响

目的探讨腹膜溶质转运特性对腹膜透析患者营养指标的影响.方法按照腹膜平衡试验(PET)计算结果,将68例稳定的连续性不卧床性腹膜透析(CAPD)患者分为高转运组(37例)和低转运组(31例).检测患者血浆和腹透透出液中的总蛋白、白蛋白及氨基酸量,同步计算蛋白质摄入量(DPI)和蛋白质分解率(nPCR).比较两组营养状态及进行相关因素分析.结果两组的残余肾功能、CAPD治疗时间、每日透析液剂量、超滤量、葡萄糖吸收量、血糖、尿素氮(BUN)、血清肌酐(Scr)和尿素清除指数(Kt/V)比较,差异无显著性意义(均P>0.05).高转运组每日经腹透透出液丢失的总蛋白质和多种氨基酸量显著高于低转运组(均P<0.05);各项营养指标均低于低转运组;两组体重及血清白蛋白比较,差异有显著性意义(均P<0.05).每日经腹透液丢失的Alb量和TAA与D/P4Scr呈正相关关系(均P<0.05).结论腹膜透析高转运患者营养指标较低转运者差,应加强对高转运患者的营养护理和指导;每日透析液量及超滤量能达到TCcr与DPI平衡即可,不宜盲目增加腹透液的剂量、浓度和存留时间,导致过度透析,引起蛋白质和氨基酸经腹透液大量丢失及吸收大量的葡萄糖,加重患者蛋白质缺乏性营养不良.     

Peritoneal ultrafiltration and fluid reabsorption during peritoneal dialysis

Peritoneal ultrafiltration and fluid reabsorption characteristics for 18 patients undergoing continuous ambulatory peritoneal dialysis (CAPD) were investigated in single dwell studies of 6 h duration with 21 of 3.86% glucose dialysis fluid. Dialysate volumes were determined in situ using radioiodinated serum albumin (RISA) as volume marker with a correction applied for the total elimination of RISA from the peritoneal cavity. The RISA elimination rate was calculated as 2.1 +/- 0.5 ml/min. The true dialysate volume after 360 min was on average 28% less than the apparent volume calculated without correction for the elimination of RISA. The mean maximum true volume plus sampling losses was 3255 ml at 240 min, corresponding to a mean net ultrafiltration volume of 762 ml between 3 min and 240 min. The mean net fluid reabsorption rate between 240 min and 360 min was 1.2 +/- 0.7 ml/min. This study of standard dialysate volume/time curves in clinically stable CAPD patients using hypertonic dialysis fluid shows that about 90% of the total net ultrafiltration is achieved during the first 90 min of the dwell. After an extended period of dialysate isovolaemia, usually lasting as long as between 120 min and 240 min, fluid reabsorption is observed in all 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.     

Comparisons of the peritoneal equilibration test and ultrafiltration in patients with and without diabetes mellitus on continuous ambulatory peritoneal dialysis

BACKGROUND/AIMS: To compare dialysance and ultrafiltration (UF) of peritoneum in diabetes mellitus (DM) and non-DM patients on continuous ambulatory peritoneal dialysis. METHODS: A total of 162 adult patients on continuous ambulatory peritoneal dialysis (40 DM and 122 non-DM patients) were studied with the peritoneal equilibration test (PET) using 2.5% glucose dialysis solution retained for 4 h. Patients using 2,000 or 1,500 ml of infusion volume were classified into groups A (23 DM and 63 non-DM patients) and B (16 DM and 41 non-DM patients), respectively. PET results were compared between DM and non-DM patients by unpaired t test. Using Pearson's correlation and least-square multiple regression, the most powerful predictors of UF rate were also evaluated in DM and non-DM patients. RESULTS: There were no differences between PET parameters and UF rate between DM and non-DM patients in the whole group (WG) and group A. The only significant difference (p < 0.05) was an increased D4/D0 value in DM patients in group B. The most simple but powerful method to predict UF rate was (100 - GAP)/(D4/D0), where GAP corresponds to the glucose absorption percentage and D4/D0 is the PET 4-hour dialysate glucose level/PET 0-hour dialysate glucose level. GAP and D4/D0 were two major determinants of UF rate in the DM group, non-DM group and WG. CONCLUSIONS: Peritoneal permeability did not differ between DM and non-DM patients, and GAP and D4/D0 were two major factors predicting UF rate.     

不同腹膜溶质转运特性腹膜透析患者营养状况的比较

目的 探讨腹膜转运特性对腹膜透析患者营养状态的影响。方法 按照腹膜平衡试验(PET)计算结果,将82例稳定的CAPD患者分为高转运组和低转运组。检测患者血浆和腹透透出液总蛋白、白蛋白及氨基酸量,同步计算蛋白质摄入量(DPI)和蛋白质分解率(nPCR)。比较两组营养状态及分析相关因素。结果两组的残余肾功能、腹透治疗时间、每日透析液剂量、超滤量、葡萄糖吸收量、血糖、BUN、Scr和Kt／V均无显著性差异。高转运组每日经腹透透出液丢失的总蛋白质和多种氨基酸量明显高于低转运组;各项营养指标均低于低转运组,且体重及血清白蛋白有显著性差异。血中及经腹透透出液丢失的白蛋白和氨基酸量均与转运类型相关。结论 腹膜透析高转运患者营养状态较低转运者差。单纯提高透析充分性并不能明显改善营养状态。要加强对高转运患者的营养管理和指导。     

Concentrations of thyroxine-binding globulin in sera and peritoneal dialysates in patients on chronic peritoneal ambulatory dialysis

Losses in thyroxine-binding globulin (TBG) in peritoneal dialysate and thyroid function were evaluated in patients undergoing continuous ambulatory peritoneal dialysis (CAPD), in comparison to patients on hemodialysis (HD) without TBG loss in the dialysate. The TBG concentration in the peritoneal dialysate was 0.26 +/- 0.09 microgram/ml (mean +/- SD, n = 24), with a daily loss of 2.47 +/- 0.94 mg. The serum TBG level in CAPD patients was 21.0 +/- 4.71 micrograms/ml (n = 24), which was not significantly different from that in HD patients (20.0 +/- 5.72 micrograms/ml, n = 24) or in healthy Japanese subjects. The serum TBG level correlated positively with the TBG loss and TBG level in the peritoneal dialysate (p less than 0.001). The serum T4 level in CAPD patients (4.93 +/- 1.38 microgram/dl, n = 24) was significantly greater than in HD patients (4.08 +/- 1.30 microgram/dl, n = 24, p less than 0.05).     

Risk factors for mortality in diabetic peritoneal dialysis patients

Objective To investigate the risk factors of all-cause mortality in diabetic patients on peritoneal dialysis (PD). Methods As a single-center retrospective cohort study, all incident PD patients who were catheterized at the First Affiliated Hospital of Nanchang University between November 1, 2005 and February 28, 2017 were included. Patients were divided into diabetes mellitus group (DM group) and non-diabetes mellitus group (NDM group). Outcomes were analyzed by Kaplan-Meier method. Multivariate Cox proportional hazards models were utilized to assess the risk factors of all-cause mortality. Results A total of 977 patients were enrolled. Compared with NDM group, patients in DM group were older (47.5±14.4 vs 59.3±11.3, P＜0.01), had more cardiovascular disease (CVD) (7.5% vs 20.3%, P＜0.01), higher levels of serum hemoglobin (78.2±17.2 vs 82.3±14.6 g/L, P＜0.01) , and lower levels of serum albumin (36.1±5.0 vs 32.7±5.6 g/L, P＜0.01). The one-, three- and five-year patient survival rates of DM and NDM group were 89.7%, 56.0%, 31.9% and 94.7%, 81.3%, 67.4%, respectively.Survival rate was significantly lower in DM group than in NDM group ( χ2=63.51, P＜0.01). Stratified analysis showed that DM group had significant lower survival rate than NDM group in patients younger than 70 years old ( χ2= 73.35, P＜0.01), while survival rate was similar between the two groups patients older than 70 years old ( χ2= 0.003, P=0.96). Multivariate Cox proportional hazards model analysis showed that DM (HR: 1.74, 95%CI: 1.27-2.38, P＜0.01), age (HR: 1.05, 95%CI: 1.04-1.06, P＜0.01), leukocyte (HR: 1.06, 95%CI: 1.00-1.12, P=0.04) and triglyceride (HR: 1.19, 95%CI: 1.07-1.32, P＜0.01) were all independent risk factors for all-cause mortality of PD patients. However, age (HR: 1.05, 95%CI: 1.04-1.07, P＜0.01) and alkaline phosphatase (HR: 1.01, 95%CI: 1.00-1.01, P=0.02) were independent risk factors for all-cause mortality of diabetic patients. Conclusions Long-term survival rate was lower in diabetic PD patients than in non-diabetic PD patients. DM, age, leukocyte and triglyceride were independent risk factors of mortality in PD patients. Age and alkaline phosphatase were independent risk factors of mortality in diabetic patients.     

Dialysate flow rate and peritoneal clearance

We evaluated the influence of dialysate flow rates upon peritoneal clearance of urea, creatine, protein losses into dialysate, glucose disappearance from dialysate, sodium removal from the patient during dialysis, and ultrafiltration rate in 64 patients undergoing intermittent peritoneal dialysis. We evaluated three dialysate flow rates: 2 L/h, 3 L/h, and 4 L/h. All dialysate contained 1.5% glucose. The clearance of urea in milliliters per minute (2-L series 14.0, 3-L series 15.1, 4-L series 17.6) and creatinine in milliliters per minute (2-L series 9.3, 3-L series 10.6, 4-L series 11.6) determined at a dialysate flow rate of 4 L/h was significantly greater than the clearances determined at 3 and 2 L/h of dialysate flow (P less than 0.05). The clearance of glucose from the peritoneal cavity in milliliters per minute (2-L series 6.9, 3-L series 7.9, 4-L series 8.9) was significantly greater for the 4-L series as compared with the 2-L series (P less than 0.05). There were no other significant differences. Neither sex, race, previous episodes of peritonitis, nor etiology of renal failure influenced the results. Given the high cost of dialysate, we recommend dialysate flows of 2 L/h if a patient has a residual renal clearance of 2.5 mL/min. Although increasing dialysate flow rate may compensate for renal clearances significantly less than this, we believe the patient should be offered hemodialysis, continuous cyclic peritoneal dialysis (CCPD), or continuous ambulatory peritoneal dialysis (CAPD).     

Venous collapsibility index changes in children on dialysis

AIM: Hypervolemia is an important factor for the development of cardiac failure in end-stage renal disease. The aims of this study are to evaluate whether collapsibility index (CI) is a useful method to assess the volume status in children on haemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD), and to test whether the small amounts of fluid removed after a single dialysis exchange will be reflected by a change in CI in peritoneal dialysis patients. METHODS: Sixteen CAPD, nine HD patients aged from 5 to 18 years and 27 age- and sex-matched healthy children were enrolled in the study. Inferior vena cava diameters were measured from subxiphoidal long axis position in 2 cm to its junction to right atrium and CI were calculated. RESULTS: The collapsibility index was significantly lower in HD patients before HD and in the CAPD group before dialysate exchange when compared with the controls. No significant difference was found between the CAPD and HD groups. We observed significant increase in CI after HD, CI values reached nearly to control levels after HD. Ultrafiltrate was 1.93 +/- 0.98 kg in HD, 0.23 +/- 0.09 kg in the CAPD group. Although the change in CI values before and after dialysate exchange was significant in the CAPD group, there was still a significant difference between the CI values of the control group and the CAPD patients after dialysate exchange. CONCLUSION: We suggest that serial measurements of CI in children will be a useful guide to assess the volume changes in an individual instead of a single measurement.     

Vitamin A losses during continuous ambulatory peritoneal dialysis

Since continuous ambulatory peritoneal dialysis (CAPD) causes losses of certain plasma proteins and their ligands, we examined the serum concentrations of vitamin A and retinol-binding protein (RBP), as well as the concentrations of vitamin A in the skin and dialysis fluid from 32 patients on CAPD over a period of 1-30 months (mean 7.5). The mean values of vitamin A and RBP in serum were 2-4 times higher than those in the healthy controls; a consistent finding in patients with chronic renal failure. Similarly, the vitamin A concentrations in skin were elevated in the CAPD patients (p less than 0.01). The vitamin A content of the dialysate (mean 1.4 mumol/24 h), which correlated significantly with the serum vitamin A concentration (r = 0.67), was constant during CAPD treatment. RBP was present in the dialysate and its concentration closely correlated with that of vitamin A (r = 0.95), indicating that the transperitoneal diffusion involved retinol-RBP. This conclusion was supported by calculations of clearance rates. Despite the considerable losses of vitamin A in CAPD fluid, the patients' vitamin A concentrations in serum and skin remained elevated. Whether extended CAPD treatment (greater than 30 months) may eventually affect the vitamin A situation in chronic renal failure warrants further observations.     

Increased risk of Staphylococcus epidermidis peritonitis in patients on dialysate containing 1.25 mmol/L calcium.

Peritoneal macrophage function is decreased in vitro in the presence of dialysate with 1.25 mmol/L calcium compared with that containing 1.75 mmol/L calcium. Theoretically, patients using this dialysate may have a higher risk of peritonitis. Nineteen patients on continuous ambulatory peritoneal dialysis (CAPD) or continuous cycling peritoneal dialysis (CCPD) were converted from dialysate with 1.75 mmol/L calcium (mean time, 33 +/- 26 months) to that with 1.25 mmol/L calcium, for some or all exchanges (mean time, 10 +/- 4.7 months). Peritonitis rates were compared with 19 control patients who remained on dialysate with 1.75 mmol/L calcium. The two groups were matched for the proportion of diabetics, sex, age, use of the Y-set, and dialysis modality (CAPD, CCPD). Peritonitis rates were similar in the study patients before conversion to 1.25 mmol/L calcium dialysate and in the control patients (0.49 v 0.58 episodes/patient-year, respectively). After conversion to dialysate with 1.25 mmol/L calcium, the peritonitis rate was 0.82 episodes/patient-year contrasted to 0.58 episodes/patient-year in the control patients (P = 0.09). The peritonitis rate due to Staphylococcus epidermidis was 0.51 episodes/patient-year when 1.25 mmol/L calcium dialysate was used, and 0.19 episodes/patient-year for the comparable period in the control patients on 1.75 mmol/L calcium dialysate (P = 0.005). The proportion of peritonitis episodes due to S epidermidis increased from 20% to 61% after conversion to 1.25 mmol/L calcium (P = 0.01). The increased risk of peritonitis due to S epidermidis in patients using dialysate with 1.25 mmol/L calcium is consistent with a previous study demonstrating that clearance of S epidermidis by peritoneal macrophages is less effective with a decrease in the dialysate calcium content.(ABSTRACT TRUNCATED AT 250 WORDS)