Correlating structure with solute and water transport in a chronic model of peritoneal inflammation

To study the process of chronic peritoneal inflammation from sterile solutions, we established an animal model to link structural changes with solute and water transport. Filtered solutions containing 4% N-acetylglucosamine (NAG) or 4% glucose (G) were injected intraperitoneally daily in 200- to 300-g rats and compared with controls (C). After 2 mo, each animal underwent transport studies using a chamber affixed to the parietal peritoneum to determine small-solute and protein mass transfer, osmotic filtration, and hydraulic flow. After euthanasia, parietal tissues were sampled for histological analysis, which demonstrated significant differences in peritoneal thickness (microm; C, 42.6 +/- 7.5; G, 80.4 +/- 22.3; NAG, 450 +/- 104; P < 0.05). Staining for VEGF correlated with CD-31 vessel counts (no./mm2: C, 53.1 +/- 16.1; G, 166 +/- 32; NAG, 183 +/- 32; P < 0.05). Tissue analysis showed treatment effects on tissue hyaluronan (micro/g: C, 962 +/- 73; G, 1,169 +/- 69; NAG, 1,428 +/- 69; P < 0.05) and collagen (microg/g: C, 56.9 +/- 12.0; G, 107 +/- 12; NAG, 97.6 +/- 11.4; P < 0.05) but not sulfated glycosaminoglycan. Transport experiments revealed no significant differences in mannitol transfer or osmotic flow. Changes were seen in hydrostatic pressure-driven flux (microl x min(-1) x cm(-2): C, 0.676 +/- 0.133; G, 0.317 +/- 0.124; NAG, 0.284 +/- 0.117; P < 0.05) and albumin transfer (microl x min(-1) x cm(-2): C, 0.331 +/- 0.028; G, 0.286 +/- 0.026; NAG, 0.229 +/- 0.025; P < 0.04). We conclude that alteration of the interstitial matrix correlates with diminished hydraulic conductivity and macromolecular transport.

The effect of peritoneal rest in combination therapy of peritoneal dialysis and hemodialysis: using the cultured human peritoneal mesothelial cell model

The effects of peritoneal rest for 24 h during peritoneal dialysis and hemodialysis combination therapy were investigated using cultured human peritoneal mesothelial cell (HPMC) models. Cell activity was investigated by 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenylterazolium bromide (MTT) assay after exposing HPMCs to peritoneal dialysis fluids (PDFs) with different pH levels. The following PDFs (50 microl/well) were used for exposure durations of 30 or 240 min: acidic heat-sterilized PDFs (L-H PDF, pH 5.5) and neutral heat-sterilized PDFs (N-H PDF, pH 6.7). Control wells were exposed to M-199 Hanks medium containing 20% fetal bovine serum (FBS) for 30 or 240 min. Supernatants were then aspirated from each well and M-199 culture medium containing 20% FBS (50 microl) was added to each well to rest HPMCs for 24 h before investigation of MTT activity. The activity of HPMCs exposed to L-H PDF for 240 min decreased to approximately 20% and 15% when compared with controls (glucose concentrations of 1.36% and 3.86%, respectively; P < 0.01 versus control, Tukey-Kramer test), and to approximately 60% and 40% after exposure to N-H PDF for 240 min (glucose: 1.36% and 3.86%; P < 0.01). The activity of HPMCs exposed to L-H PDF for 240 min followed by rest was approximately 20% and 4% when compared with controls (glucose: 1.36% and 3.86%; P < 0.01) and was 93% and 96% when compared with controls after exposure to N-H PDF for 240 min followed by rest (glucose: 1.36% and 3.86%). These findings suggest that rest for 24 h after exposure to N-H PDF improves the activity of HPMCs.

Impact of Mode of Dialysis on Intra-abdominal Infection after Simultaneous Pancreas-Kidney Transplantation

BACKGROUND

Whether peritoneal dialysis is a risk factor for the development of intra-abdominal infection (IAI) after simultaneous pancreas kidney (SPK) transplantation is controversial.

METHODS

We investigated the incidence of IAI, and patient and pancreas graft survival rates of 120 patients that received SPK between November 1995 and August 2003. All patients were dialysis-dependent prior to transplantation; mean duration of peritoneal dialysis (PD; n=52) and hemodialysis (HD; n=68) was 20+/-15 months and 23+/-16 months, respectively.

RESULTS

IAI developed in five PD and six HD patients (P=0.88). The time of diagnosis of IAI and the spectrum of organisms cultured were similar in the two groups of patients. Age, duration of dialysis, and method of exocrine drainage did not have a significantly impact on infection rate. Patient and pancreas graft survival rates were 92.3% and 88.4% in the PD group and 95.5% and 92% HD group (p=ns) after a mean follow-up of 42+/-27 months and 39+/-27 months, respectively. Overall patient and pancreas graft survival was not significantly affected by IAI.

CONCLUSIONS

PD does not adversely affect IAI rate and is a safe mode of dialysis for patients awaiting SPK transplantation.

Peritoneal resuscitation

BACKGROUND

After resuscitation from hemorrhagic shock, intestinal microvessels constrict leading to impaired mucosal blood flow. This occurs despite restoration of central hemodynamics. We review studies on the use of peritoneal dialysis fluid as an adjunct treatment in amelioration of this gut hypoperfusion.

METHODS

Using in vivo microscopy of the intestinal microcirculation, the effects of topically applied dextrose-based peritoneal dialysis fluid was measured. In other words, animal experiments, the survival benefits, the morbidity, blood flow distribution, and the postresuscitation inflammatory response to direct peritoneal resuscitation (DPR) were determined.

RESULTS

Simulated DPR caused a dramatic vasodilation compared with a progressive vasoconstriction when used during conventional resuscitation (CR) from hemorrhagic shock. It also reversed established vasoconstriction 2 and 4 hours after CR. In CR animals, there was a 40% mortality compared with 100% survival in DPR animals. DPR resulted in a downregulation of the gut-associated proinflammatory response noted after CR and similarly prevented edema formation.

CONCLUSION

DPR enhances organ blood flow to organs incited in the pathogenesis of multiple organ failure and improves survival after severe hemorrhage and CR.

Evaluation of intraperitoneal pressure and the effect of different osmotic agents on intraperitoneal pressure in children

OBJECTIVES

To establish intraperitoneal pressure (IPP) in a relatively large pediatric study group and to study the effects of a 3.86% glucose solution and a 7.5% icodextrin solution on IPP during a 4-hour dwell.

DESIGN

IPP was measured with the patient in a supine position. The intraperitoneal volume (IPV) was 1200 mL/m2 with a 1.36% glucose solution. The influence of dialysis solutions was obtained by performing two 4-hour peritoneal equilibration tests (PETs) with 3.86% glucose and 7.5% icodextrin as test solution, using an IPV of 1200 mL/m2 and dextran 70 as volume marker. IPP was measured at two consecutive time points (t = 0 and t = 240 minutes). Transcapillary ultrafiltration, net ultrafiltration, and marker clearance were calculated.

PATIENTS

IPP was established in 30 patients with median age of 4.5 years (range 1.0 - 14.9 years). Influence of dialysis solutions on IPP was studied in 9 children with median age of 4.2 years (range 1.7 - 10.9 years) and median treatment period of 12 months (range 5.6 - 122.3 months).

RESULTS

Mean IPP was 12.0 +/- 6.5 cm H2O. Significant relations were found between the change in IPP and transcapillary ultrafiltration and body surface area during the PET with 3.86% glucose. No relations were seen during the PET with icodextrin.

CONCLUSIONS

IPP was established in a large pediatric study group and was similar to previously published values of IPP in a small number of patients. Differences in fluid kinetics have different effects on the change in IPP during a 4-hour dwell period.

Pharmacokinetics of intraperitoneal cefepime in automated peritoneal dialysis

OBJECTIVE

This study determined the pharmacokinetics of intraperitoneal (IP) cefepime in automated peritoneal dialysis (APD) patients.

DESIGN AND METHODS

A prospective pharmacokinetic study was performed in 6 noninfected adult APD patients. All patients were administered a single IP dose of cefepime (15 mg/kg) over a 6-hour dwell. Patients then underwent a fixed APD regimen consisting of the first 6-hour dwell, followed by an 8-hour dialysate-free period and a subsequent series of 3 overnight APD exchanges. Blood and dialysate samples were collected at t = 0, 1, 2, 4, 6 (end of dwell), and 24 hours. Any urine produced during the study period was collected. Cefepime concentrations in serum, dialysate, and urine were determined by liquid chromatography mass spectrometry. Pharmacokinetic parameters were calculated assuming a mono-exponential model.

RESULTS

One hour after IP administration, serum cefepime levels exceeded the minimum inhibitory concentration (8 microg/mL) for susceptible organisms. The mean serum and dialysate concentrations at 24 hours were 15.8 +/- 3.6 and 6.2 +/- 2.3 microg/mL respectively. Bioavailability was 84.3% +/- 6.2%, volume of distribution 0.34 +/- 0.07 L/kg, and serum half-life 13.8 +/- 3.2 hours. Total, peritoneal, and renal clearances were 16.5 +/- 4.4, 4.3 +/- 0.7, and 3.5 +/- 2.5 mL/minute, respectively.

CONCLUSIONS

IP cefepime dosed at 15 mg/kg resulted in adequate serum concentrations in APD patients at 24 hours post dose. Pharmacokinetic predictions suggest that most APD and CAPD patients would achieve adequate serum cefepime concentrations if treated with standard doses of 1000 mg given IP once daily. Patients using APD regimens different from that used in this study, anuric patients, and those with significant residual renal function may require a more individualized approach.

Low molecular weight heparin improves peritoneal ultrafiltration and blocks complement and coagulation

OBJECTIVES

Clinical studies have demonstrated that the intraperitoneal (IP) complement and coagulation systems are activated in peritoneal dialysis (PD) patients. In animal models, low molecular weight heparin (LMWH) was seen to inhibit peritoneal angiogenesis, and related compounds have increased ultrafiltration volumes after repeated administration to PD patients. The present study evaluated the effects of LMWH on ultrafiltration, coagulation, and complement activation during a single PD dwell.

DESIGN

Rats were exposed to a single dose of 20 mL 2.5% glucose-based, filter-sterilized PD fluid, with or without supplementation with LMWH. The PD fluid was administered either as an IP injection or as an infusion through an indwelling catheter. The dwell fluid was analyzed 2 hours later concerning activation of the complement and coagulation cascades, chemotactic activity, neutrophil recruitment, ultrafiltration volume, and glucose and urea concentrations.

RESULTS

Exposure to PD fluid induced activation of IP complement [formation of C3a (desArg) and increase of C5a-dependent chemotactic activity] and coagulation (formation of thrombin-antithrombin complex) and recruitment of neutrophils. In the case of IP injection, neutrophil recruitment and complement activation were inhibited by LMWH. In both models, LMWH inhibited thrombin formation, reduced complement-dependent chemotactic activity, and increased the IP fluid volume, indicating an improved ultrafiltration.

CONCLUSIONS

The acute inflammatory reaction to PD fluid involves the complement and coagulation cascades. Addition of LMWH to the PD fluid improves ultrafiltration, inhibits formation of thrombin, and potentially blocks C5a activity. The present results motivate further investigations of the IP cascade systems in PD.

The Management of Abdominal Aortic Aneurysms in Patients with Concurrent Renal Impairment

INTRODUCTION

Patients with concurrent renal impairment and abdominal aortic aneurysms present a significant challenge in terms of pre-operative, intra-operative and post-operative management. This aim of this review was to determine the risks of surgery in this patient group and determine whether any clear management strategies exist to enhance their clinical management.

METHODS

Systematic review of published literature giving details of the outcome of open or endovascular abdominal aortic aneurysm repair in patients with pre-operative renal impairment. Papers concerning the management of post-operative acute renal failure in patients with normal pre-operative renal function has not been included.

RESULTS

There is little data regarding patients with end-stage renal failure and AAA although these patients appear to have a high peri-operative mortality rate. In contrast, those with renal impairment do not have a significantly higher mortality rate than those with normal renal function, rather they have a higher risk of complications associated with surgery and may require more intensive post-operative organ system support than normal patients. Many have a transient deterioration in renal function in the immediate peri-operative period that will resolve. In the case of patients with ruptured AAA, it is not clear whether pre-operative renal impairment affects mortality.

Peritoneal dialysis

Peritoneal dialysis has much to offer patients with chronic renal failure who wish to manage their care and live relatively independent lives. The authors discuss different peritoneal dialysis treatments, patient selection, benefits and the management of potential complications.

Dialysis choice in the context of an early referral policy: there is room for self care

BACKGROUND

Predialysis care is vital for the patient and is crucial for dialysis choice: empowered, early referred patients tend to prefer out-of-hospital and self-care treatment; despite these claims, early referral remains too often a program more than a reality. Aim of the study was to evaluate the pattern and reasons for RRT choice in patients treated in a long-standing outpatient network, presently following 850 chronic patients (about 80% diabetics), working with an early referral policy and offering a wide set of dialysis options (home hemo and PD; self care and limited care hemodialysis; hospital hemodialysis).

METHODS

Prospective historical study. All patients who started RRT in January 2001-December 2003 were considered. Correlations between demographical (sex, age, educational level) or clinical variables (pre-RRT follow-up, comorbidity, SGA and Karnofsky) and treatment choice have been tested by univariate (chi-square, Kruskal-Wallis) and multivariate models (logistic regression), both considering all choices and dichotomising choice into "hospital" versus "out of hospital dialysis".

RESULTS

Hospital dialysis was chosen by 32.6% of patients; out of hospital in 67.4% (PD 26.5%, limited-care 18.4%, home hemodialysis 4.1%, self-care 18.4%). Hospital dialysis and PD were chosen by elderly patients (median age: 67.5 and 70 years respectively) with multiple comorbidities (75% and 92.3%); no difference for age, comorbidity, Karnofsky, SGA and educational level. 6/13 PD patients needed the help of a partner. Self-care/home hemodialysis patients were younger (median age 52), had higher educational level (p = 0.014) and lower prevalence of comorbidity (63.6% vs 94.7% in the other dialysis patients, p = 0.006). In the context of a long follow-up period (3.9 years) a statistically significant difference was found comparing hospital dialysis (3.3 years) vs out of hospital dialysis (4.9 years) (p = 0.035). In a logistic regression model, only pre-RRT follow-up was correlated with dialysis "hospital vs "out of hospital" choice (p = 0.014).

CONCLUSION

Early nephrological follow-up may enhance self and home-based dialysis care.

Icodextrin re-absorption varies with age in children on automated peritoneal dialysis

Information on the use of Icodextrin in children remains scarce; however, it is believed that the characteristics are similar across all ages. We report the use of Icodextrin in a cohort of pediatric automated peritoneal dialysis (APD) patients younger than those previously reported (n=8, median age of 2.8, range 0.02-17.1 years). Net Icodextrin daytime dwell ultrafiltration was calculated in each patient for every day on therapy as ml/h/m2. Half of the patients showed re-absorption even when reducing Icodextrin dwells from a median of 10 to 6 h. All four patients who re-absorbed the Icodextrin (ranging from -23.7+/-7.5 to -2.5+/-6.0 ml/h/m2) were treated with cyclic nocturnal APD, and three of these four patients were high transporters on the peritoneal equilibration test (PET). Icodextrin fluid removal correlated significantly with age (Spearman rank r=0.8571, P=0.0107). The data suggest that Icodextrin behaves differently in young children.

Direct peritoneal resuscitation from hemorrhagic shock: effect of time delay in therapy initiation

BACKGROUND

After conventional resuscitation from hemorrhagic shock, splanchnic microvessels progressively constrict, leading to impairment of blood flow. This occurs despite restoration and maintenance of central hemodynamics. The authors' recent studies have demonstrated that topical and continuous ex vivo exposure of the gut microvasculature to a glucose-based clinical peritoneal dialysis solution (Delflex), as a technique of direct peritoneal resuscitation (DPR), can prevent these postresuscitation events when initiated simultaneously with conventional resuscitation. This study aimed to determine whether DPR applied after conventional resuscitation reverses the established postresuscitation intestinal vasoconstriction and hypoperfusion.

METHODS

Male Sprague-Dawley rats were bled to 50% of baseline mean arterial pressure and resuscitated intravenously over 30 minutes with the shed blood returned plus two times the shed blood volume of saline. Initiation of ex vivo, topical DPR was delayed to 2 hours (group 1, n = 8), or to 4 hours (group 2, n = 8), respectively, after conventional resuscitation. Intravital microscopy and Doppler velocimetry were used to measure terminal ileal microvascular diameters of inflow A1 and premucosal A3 (proximal pA3, distal dA3) arterioles and blood flow in the A1 arteriole, respectively. Maximum arteriolar dilation capacity was obtained from the topical application, in the tissue bath, of the endothelium-independent nitric oxide-donor sodium nitroprusside (10M).

RESULTS

Hemorrhagic shock caused a selective vasoconstriction of A1 (-24.1% +/- 2.15%) arterioles from baseline, which was not seen in A3 vessels. This caused A1 blood flow to drop by -68.6% of the prehemorrhage value. Conventional resuscitation restored and maintained hemodynamics in all the animals without additional fluid therapy. In contrast, there was a generalized and progressive postresuscitation vasoconstriction of A1 (-21.7%), pA3 (-18.5%), and dA3 (-18.7%) vessels. The average postresuscitation A1 blood flow was -49.5% of the prehemorrhage value, indicating a persistent postresuscitation hypoperfusion. Direct peritoneal resuscitation reversed the postresuscitation vasoconstriction by 40.9% and enhanced A1 blood flow by 112.9% of the respective postresuscitation values.

CONCLUSIONS

Delayed DPR reverses the gut postresuscitation vasoconstriction and hypoperfusion regardless of the initiation time. This occurs without adverse effects on hemodynamics. Direct peritoneal resuscitation-mediated enhancement of tissue perfusion results from the local effects from the vasoactive components of the Delflex solution, which are hyperosmolality, lactate buffer anion, and, to a lesser extent, low pH. The molecular mechanism of this vasodilation effect needs further investigation.

Predictive factors of low HCO3– levels in peritoneal dialysis patients

BACKGROUND

Metabolic acidosis is a major metabolic abnormality in end-stage renal disease (ESRD) and alkali is provided with dialysis treatment to patients on chronic peritoneal dialysis (CPD) to keep their acid-base balance within normal serum HCO3- levels.

METHODS AND RESULTS

We examined the levels of venous serum HCO3- in 163 patients on CPD and the predictive factors for HCO3- levels low enough to indicate metabolic acidosis. The mean value for HCO3- was 26+/-2.4 mmol/l and for anion gap was 13.1+/-3.1 mEq/l. A serum bicarbonate concentration of less than 24 mmol/l, compatible with metabolic acidosis, was observed in 13.5% of the patients. In a multivariate analysis HCO3- levels were directly correlated with older age and use of CaCO3- as phosphate binders, and inversely associated with serum potassium, the use of sevelamer and low lactate dialysis solutions. Higher serum urea levels, the use of low lactate solutions and sevelamer instead of CaCO3 were significantly predictive factors for HCO3- levels < 24 mmol/l.

CONCLUSIONS

Venous HCO3- and anion gap values were within the normal ranges in stable CPD patients. In 13.5% of them, however, chronic metabolic acidosis was observed based on venous HCO3- levels < 24 mmol/l. Dietary protein intake, the use of sevelamer and low (35 mmol/l) concentration of lactate in dialysis solutions are important predictive factors for chronic metabolic acidosis in these patients.

[Selection of peritoneal dialysis schemes based on multi-objective fuzzy pattern recognition]

The fuzziness in the selection of peritoneal dialysis schemes is discussed. A method of multi-objective fuzzy pattern recognition and its application in the selection of peritoneal dialysis schemes are presented. The method was first applied to the field of peritoneal dialysis. The conclusion showed that this method agreed with doctors' opinions. It provides a new idea for research in this field. At the same time, since the method is simple and easy to use, it can be of wide application.

[Peritoneal dialysis with allogenic hepatic cell suspension in treatment of hepatic insufficiency]

Increasing prevalence of patients with liver diseases results in growth of morbidity caused by liver insufficiency. The comparative analysis of the different methods (hemosorption, hemofiltration, plasmapheresis, liver cell transplantation) for the treatment of the hepatic failure showed that the mortality rate of such patients remains to be high. Ex vivo blood treatment can be divided into three categories: passive detoxification, liver perfusion and bioartificial or cell-based systems. A cellular dialyzing fluid was used in rats to evaluate efficacy of peritoneal dialysis in the treatment of hepatic insufficiency. The results of treatment of animals suffering from acute toxic disease of the liver indicate to the high therapeutic effectiveness of such dialysis. Cellular peritoneal dialysis did not induce anaphylactic reactions in animals. Favorable dynamics of changes in the biochemical, clinical and morphological induces were noted, which allows this method to be recommended for clinical approbation.

Choix d’une méthode de dialyse par les malades insuffisants rénaux

The principal options for treatment of end-stage renal disease are hospital, out-center, self-or home hemodialysis or continuous ambulatory or automated peritoneal dialysis. Hemodialysis and peritoneal dialysis were long considered competitive methods, but they have become complementary and the same patient can use them successively at different life stages. The choice of technique usually depends on family, personal, social and work factors, rather than the medical situation. The healthcare team provides guidance to the patient in making this choice. The choice of treatment is optimal when the referral is early.

Longitudinal membrane function in functionally anuric patients treated with APD: Data from EAPOS on the effects of glucose and icodextrin prescription

BACKGROUND

Peritoneal dialysis is associated with changes in membrane function that can lead eventually to ultrafiltration (UF) failure. Factors driving these changes are thought to include hypertonic glucose exposure, but previously reported associations are confounded by the presence of residual renal function.

METHODS

Longitudinal membrane function (solute transport and UF capacity) were measured annually in a prospective cohort of 177 functionally anuric patients as part of the European Automated Peritoneal Dialysis Outcomes Study (EAPOS). Subgroup analysis was performed according to glucose exposure and icodextrin use at baseline.

RESULTS

The whole cohort experienced an increase in solute transport and reduction in UF capacity at 12 and 24 months that could not be explained by informative censoring. These changes were accelerated and more severe in patients using either 2.27% or 3.86% glucose, or those not using icodextrin at baseline. These differences could not be explained by age, comorbidity score, previous time spent on renal replacement, differential dropout from the study, peritonitis rates, or, by definition, residual renal function. Patients using icodextrin at baseline had worse membrane function and were more likely to be diabetic. There was an association between membrane function changes and achieved 24-hour ultrafiltration over the 2-year study period.

CONCLUSION

Anuric automated peritoneal dialysis (APD) patients experience significant detrimental changes in membrane function over a relatively short time period. Glucose appears to enhance these changes independent of residual renal function. Icodextrin use in these circumstances is associated with less deterioration in membrane function.

Adiponectin in peritoneal dialysis patients: a comparison with hemodialysis patients and subjects with normal renal function

BACKGROUND

Adiponectin, a cytokine with anti-inflammatory properties that is secreted from adipose tissue, is associated with insulin resistance. Adiponectin has been shown to be a predictor of cardiovascular events in both the general population and patients undergoing hemodialysis (HD); however, its role in peritoneal dialysis (PD) analogues remains unclear.

METHODS

Serum adiponectin levels, measured by means of enzyme-linked immunosorbent assay in subjects with normal renal function and patients undergoing HD or PD (28 subjects in each group), were analyzed to establish the relationship between adiponectin and lipid levels, as well as insulin resistance. In the second study, 104 PD patients were recruited to analyze the relationships between serum adiponectin level and residual renal and peritoneal function and C-reactive protein (CRP) level. Independent factors for serum adiponectin level were determined from multiple linear regression.

RESULTS

No significant difference was shown comparing serum adiponectin levels of PD and HD patients; however, both were significantly greater than those of control subjects (P < 0.01). Negative associations were shown between adiponectin and triglyceride (TG; P < 0.01) and insulin levels (P < 0.05) and homeostatic model assessment of insulin resistance (P < 0.01) for the former 2 groups; however, a positive association was shown for high-density lipoprotein (HDL) level (P < 0.05). Neither HD nor PD removed adiponectin significantly, with levels for the PD group negatively associated with residual renal function (P < 0.01) and CRP level (P < 0.001). PD patients administered glucose-lowering agents had lower adiponectin levels; however, lipid-lowering agents and renin-angiotensin blockades did not appear to affect them. Independent determinants for serum adiponectin level in PD patients were TG, HDL, and CRP levels and body mass index, after adjustment for age, sex, PD therapy duration, and diabetes. Adiponectin levels were not associated with left ventricular mass or ejection fraction. As for HD patients, PD patients had high adiponectin levels; adiponectin was not removed effectively using either of the studied dialysis modalities. In addition to a significant relationship with the components of insulin resistance, adiponectin level was associated with CRP level in these patients.

CONCLUSION

These results indicate that adiponectin level in PD patients may be a good indicator of cardiovascular disease risk.

Dialysate as Food: Combined Amino Acid and Glucose Dialysate Improves Protein Anabolism in Renal Failure Patients on Automated Peritoneal Dialysis

Protein-energy malnutrition as a result of anorexia frequently occurs in dialysis patients. In patients who are on peritoneal dialysis (PD), dialysate that contains amino acids (AA) improves protein anabolism when combined with a sufficient oral intake of calories. It was investigated whether protein anabolism can be obtained with a mixture of AA plus glucose (G) as a source of proteins and calories during nocturnal automated PD (APD). A random-order cross-over study was performed in eight APD patients to compare in two periods of 7 d each AA plus G dialysate obtained by cycler-assisted mixing of one bag of 2.5 L of AA (Nutrineal 1.1%, 27 g of AA) and four bags of 2.5 L of G (Physioneal 1.36 to 3.86%) versus G as control dialysate. Whole-body protein turnover was determined using a primed continuous infusion of L-[1-13C]leucine, and 24-h nitrogen balance studies were performed. During AA plus G dialysis, when compared with control, rates of protein synthesis were 1.20 +/- 0.4 and 1.10 +/- 0.2 micromol/kg per min leucine (mean +/- SD), respectively (NS), and protein breakdown rates were 1.60 +/- 0.5 and 1.72 +/- 0.3 micromol/kg per min (NS). Net protein balance (protein synthesis minus protein breakdown) increased on AA plus G in all patients (mean 0.21 +/- 0.12 micromol leucine/kg per min; P < 0.001). The 24-h nitrogen balance changed by 0.96 +/- 1.21 g/d, from -0.60 +/- 2.38 to 0.35 +/- 3.25 g/d (P = 0.061, NS), improving in six patients. In conclusion, APD with AA plus G dialysate improves protein kinetics. This dialysis procedure may improve the nutritional status in malnourished PD patients.

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.

Peritoneal catheters and exit-site practices toward optimum peritoneal access: a review of current developments

OBJECTIVE

This review updates the 1998 International Society for Peritoneal Dialysis (ISPD) recommendations for peritoneal dialysis catheters and exit-site practices (Gokal R, et al. Peritoneal catheters and exit-site practices toward optimum peritonealaccess: 1998 update. Perit Dial Int 1998; 18:11-33.)

DESIGN

DATA SOURCES

The Ovid and PubMed search engines were used to review the Medline databases of January 1980 through June 2003. Searches were restricted to human data; primary key word searches included dialysis, peritoneal dialysis, and continuous ambulatory peritoneal dialysis cross referenced with access, catheter, dialysis catheter, peritoneal dialysis catheter, and Tenckhoff catheter. Related searches were provided via the PubMed related articles link.

STUDY SELECTION

Reports were selected if they provided identifiable information on catheter design, catheter placement technique, and survival or placement complications. Reports without such data were excluded from review. Each study was then categorized by its characteristics: single-center or multicenter; retrospective or prospective; controlled trial, with or without random patient assignment; or review article.

MAIN RESULTS

There are few randomized controlled evaluations testing how catheter design and/or placement influence long-term survival and function, and these are typically conducted at a single center. The majority of reports represent retrospective single-center experiences, and these are supplemented by occasional multicenter data registries.

CONCLUSIONS

There is substantial variability in catheter outcomes between centers, and this variability is more closely correlated with operator and center characteristics than with catheter design. Some catheter designs appear to impact long-term catheter success, and, in some cases, specific patient characteristics and dialysis formats combine with specific catheter designs to influence catheter survival. Most reporters prefer two-cuff designs and placement of the deep cuff at an intramuscular location. Intramuscular cuff placement results in fewer pericatheter leaks and hernias, but makes catheter removal more difficult. High-risk patients (those with previous pelvic surgery) benefit from visual inspection of the peritoneum during catheter placement, and in randomized controlled trials, catheters with pre-shaped arcuate subcutaneous segments ("swan neck" designs) reduce the risk of early drainage failure via "migration."