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

Sodium handling in pediatric patients on maintenance dialysis

The risk of cardiovascular disease remains exceedingly high in pediatric patients with chronic kidney disease stage 5 on dialysis (CKD 5D). Sodium (Na+) overload is a major cardiovascular risk factor in this population, both through volume-dependent and volume-independent toxicity. Given that compliance with a Na+-restricted diet is generally limited and urinary Na+ excretion impaired in CKD 5D, dialytic Na+ removal is critical to reduce Na+ overload. On the other hand, an excessive or too fast intradialytic Na+ removal may lead to volume depletion, hypotension, and organ hypoperfusion. This review presents current knowledge on intradialytic Na+ handling and possible strategies to optimize dialytic Na+ removal in pediatric patients on hemodialysis (HD) and peritoneal dialysis (PD). There is increasing evidence supporting the prescription of lower dialysate Na+ in salt-overloaded children on HD, while improved Na+ removal may be achieved in children on PD with an individual adaptation of dwell time and volume and with icodextrin use during the long dwell.

Factors related to ultrafiltration volume with icodextrin dialysate use in children

BACKGROUND

Icodextrin has a lower absorption rate, and icodextrin peritoneal dialysate contributes to more water removal than glucose dialysate in patients with high peritoneal permeability. There are limited data on icodextrin dialysate use in children.

METHODS

This study included all pediatric patients who received peritoneal equilibration tests and peritoneal dialysis with icodextrin dialysate at the study center. The factors related to ultrafiltration volume with icodextrin dialysate with long dwell time were statistically analyzed. Then the ultrafiltration volume with icodextrin and medium-concentration glucose dialysate was compared in individual cycles in the same patients.

RESULTS

Thirty-six samples were included in the icodextrin group, and nine samples were used to compare the ultrafiltration volume with icodextrin and glucose dialysate. Dwell time, D/P-creatinine, D/D₀-glucose, age, height, and weight correlated significantly with the ultrafiltration volume of icodextrin dialysate (p < 0.05). A dwell volume equal to or more than 550 mL/m² was associated with a significantly higher ultrafiltration volume than a lower dwell volume (p = 0.039). Multiple regression analysis revealed that dwell time (p = 0.038) and height (p < 0.01) correlated with ultrafiltration volume significantly. In addition, the ultrafiltration volume was superior (p < 0.01), and dwell time was longer (p = 0.02), with icodextrin dialysate than with medium-concentration glucose dialysate.

CONCLUSIONS

The ultrafiltration volume with icodextrin dialysate decreases in patients with small stature. Providing sufficient dwell time and volume is important for maximal water removal even in children. Ultrafiltration volume is superior with icodextrin than medium-concentration glucose dialysate for long dwell times. A higher resolution version of the Graphical abstract is available as Supplementary information.

Prescribing peritoneal dialysis for high-quality care in children

Background:

Peritoneal dialysis (PD) remains the most widely used modality for chronic dialysis in children, particularly in younger children and in lower and middle income countries (LMICs). We present guidelines for dialysis initiation, modality selection, small solute clearance, and fluid removal in children on PD. A review of the literature and key studies that support these statements are presented.

Methods:

An extensive Medline search for all publications on PD in children was performed using predefined search criteria.

Results:

High-quality randomized trials in children are scarce and current clinical practice largely relies on data extrapolated from adult studies or drawn from observational cohort studies in children. The evidence and strength of the recommendation is GRADE-ed, but in the absence of high-quality evidence, the opinion of the authors is provided and must be carefully considered by the treating physician, and adapted to local expertise and individual patient needs as appropriate. We discuss the timing of dialysis initiation, factors to be considered when selecting a dialysis modality, the assessment and management of volume status on PD, achieving optimal small solute clearance, and the importance of preserving residual kidney function. While optimal dialysis must remain the goal for every patient, a careful discussion with fully informed patients and caregivers is important to understand the patient and family’s expectations of dialysis and reasonable adjustments to the dialysis program may be considered in accordance with a philosophy of shared decision-making.

Conclusions:

There continues to be very poor evidence in the field of chronic PD in children and these recommendations can at best serve to guide clinical decision-making. In LMICs, every effort should be made to conform to the framework of these statements, taking into account resource limitations.

Impact of fill volume on ultrafiltration with icodextrin in children on chronic peritoneal dialysis

BACKGROUND

Icodextrin is a solution of glucose polymers developed to provide sustained ultrafiltration over an extended dwell. Our aim was to determine whether or not fill volume with icodextrin contributes to the ability to achieve ultrafiltration in children.

METHODS

The charts of all children on chronic peritoneal dialysis between January 2000 and July 2014 were screened for the use of an icodextrin day dwell. Data were extracted from the electronic chart and the HomeChoice™ Pro card and corrected for body surface area (BSA).

RESULTS

Fifty children had an icodextrin day dwell. A linear correlation was found between the daytime fill volume and net ultrafiltration (p < 0.001). More ultrafiltration was achieved with a fill volume above 550 ml/m(2) BSA (107 ± 75 ml/m(2) BSA) than with smaller fill volumes (-8 ± 99 ml; p = 0.004). Ultrafiltration was achieved in 88 % of children with a fill volume above 550 ml/m(2) BSA versus only 44 % of patients with a smaller fill volume (p = 0.001). Icodextrin was well tolerated.

CONCLUSIONS

Our observations reveal that the larger the fill volume the higher the likelihood of achieving ultrafiltration with icodextrin and suggest that a minimum day dwell volume of 550 ml/m(2) BSA seems to facilitate ultrafiltration in children. To our knowledge this is the largest study addressing ultrafiltration with icodextrin in children.

Quantitative Histomorphometry of the Healthy Peritoneum

The peritoneum plays an essential role in preventing abdominal frictions and adhesions and can be utilized as a dialysis membrane. Its physiological ultrastructure, however, has not yet been studied systematically. 106 standardized peritoneal and 69 omental specimens were obtained from 107 patients (0.1–60 years) undergoing surgery for disease not affecting the peritoneum for automated quantitative histomorphometry and immunohistochemistry. The mesothelial cell layer morphology and protein expression pattern is similar across all age groups. Infants below one year have a thinner submesothelium; inflammation, profibrotic activity and mesothelial cell translocation is largely absent in all age groups. Peritoneal blood capillaries, lymphatics and nerve fibers locate in three distinct submesothelial layers. Blood vessel density and endothelial surface area follow a U-shaped curve with highest values in infants below one year and lowest values in children aged 7–12 years. Lymphatic vessel density is much lower, and again highest in infants. Omental blood capillary density correlates with parietal peritoneal findings, whereas only few lymphatic vessels are present. The healthy peritoneum exhibits major thus far unknown particularities, pertaining to functionally relevant structures, and subject to substantial changes with age. The reference ranges established here provide a framework for future histomorphometric analyses and peritoneal transport modeling approaches.

Optimizing peritoneal dialysis prescription for volume control: the importance of varying dwell time and dwell volume

Not only adequate uremic toxin removal but also volume control is essential in peritoneal dialysis (PD) to improve patient outcome. Modification of dwell time impacts on both ultrafiltration (UF) and purification. A short dwell favors UF but preferentially removes small solutes such as urea. A long dwell favors uremic toxin removal but also peritoneal fluid reabsorption due to the time-dependent loss of the crystalloid osmotic gradient. In particular, the long daytime dwell in automated PD may result in significant water and sodium reabsorption, and in such cases icodextrin should be considered. Increasing dwell volume favors the removal of solutes such as sodium due to the increased volume of diffusion and the recruitment of peritoneal surface area. A very large fill volume with too high an intraperitoneal pressure (IPP) may, however, result in back-filtration and thus reduced UF and sodium clearance. Based on these principles and the individual transport and pressure kinetics obtained from peritoneal equilibration tests and IPP measurements, we suggest combining short dwells with a low fill volume to favor UF with long dwells and a large fill volume to favor solute removal. Results from a recent randomized cross-over trial and earlier observational data in children support this concept: the absolute UF and UF relative to the administered glucose increased and solute removal and blood pressure improved.

Strategies for the preservation of residual renal function in pediatric dialysis patients

In adults with end-stage renal disease (ESRD), the preservation of residual renal function (RRF) has been shown to be associated with decreased mortality and improved control of complications of chronic kidney disease. However, less is known on the benefits of RRF in the pediatric dialysis population. The purpose of this article is to review the clinical significance of RRF and to discuss strategies for the preservation of RRF in children with ESRD.

Clinical practice recommendations for the care of infants with stage 5 chronic kidney disease (CKD5)

BACKGROUND

To provide recommendations for the care of infants with stage 5 chronic kidney disease (CKD5).

SETTING

European Paediatric Dialysis Working Group.

DATA SOURCES

Literature on clinical studies involving infants with CKD5 (end stage renal failure) and consensus discussions within the group.

RECOMMENDATIONS

There has been an important change in attitudes towards offering RRT (renal replacement therapy) to both newborns and infants as data have accumulated on their improved survival and long-term outcomes. The management of this challenging group of patients differs in a number of ways from that of older children. The authors have summarised the basic recommendations for treating infants with CKD5 in order to support the multidisciplinary teams who endeavour on this difficult task.

Advances in pediatric renal replacement therapy

Advances in the understanding and clinical application of hemodialysis, peritoneal dialysis, and continuous renal replacement therapy have resulted in strategies designed to further improve their safety and efficacy. These advances have been particularly important to children, in whom a variety of clinical and technical issues must be taken into consideration for optimum dialysis across a broad spectrum of patient size and need. This manuscript reviews recent data pertaining to the use of renal replacement therapy, with an emphasis on those aspects of dialysis management that are especially pertinent to pediatric ESRD and acute kidney injury care.

Peritoneal dialysis in infants and young children

Although end-stage renal disease is rare in infants and young children, its development can be associated with significant morbidity and mortality and only through the provision of experienced, multidisciplinary care can a favorable outcome be anticipated. Peritoneal dialysis is the renal replacement modality of choice for this age group and serves as an essential bridge until successful renal transplantation can occur. In this review, we discuss the practice of peritoneal dialysis in infants including the unique ethical and technical considerations facing pediatric nephrologists and caregivers. In addition, we review current guidelines concerning nutrition, growth, and adequacy, as well as the literature on complications and outcomes.

Solutions for peritoneal dialysis in children: recommendations by the European Pediatric Dialysis Working Group

The purpose of this article is to provide recommendations on the choice of peritoneal dialysis (PD) fluids in children by the European Pediatric Dialysis Working Group. The literature on experimental and clinical studies with PD solutions in children and adults was analyzed together with consensus discussions within the group. A grading was performed based on the international KDIGO nomenclature and methods. The lowest glucose concentration possible should be used. Icodextrin may be applied once daily during the long dwell, in particular in children with insufficient ultrafiltration. Infants on PD are at risk of ultrafiltration-associated sodium depletion, while anuric adolescents may have water and salt overload. Hence, the sodium chloride balance needs to be closely monitored. In growing children, the calcium balance should be positive and dialysate calcium adapted according to individual needs. Limited clinical experience with amino acid-based PD fluids in children suggests good tolerability. The anabolic effect, however, is small; adequate enteral nutrition is preferred. CPD fluids with reduced glucose degradation products (GDP) content reduce local and systemic toxicity and should be preferred whenever possible. Correction of metabolic acidosis is superior with pH neutral bicarbonate-based fluids compared with single-chamber, acidic, lactate-based solutions. Prospective comparisons of low GDP solutions with different buffer compositions are still few, and firm recommendations cannot yet be given, except when hepatic lactate metabolism is severely compromised.

Peritoneal dialysis prescription in children: bedside principles for optimal practice

There is no unique optimal peritoneal dialysis prescription for all children, although the goals of ultrafiltration and blood purification are universal. In turn, a better understanding of the physiology of the peritoneal membrane, as a dynamic dialysis membrane with an exchange surface area recruitment capacity and unique permeability characteristics, results in the transition from an empirical prescription process based on clinical experience alone to the potential for a personalized prescription with individually adapted fill volumes and dwell times. In all cases, the prescribed exchange fill volume should be scaled for body surface area (ml/m(2)), and volume enhancement should be conducted based on clinical tolerance and intraperitoneal pressure measurements (IPP; cmH(2)O). The exchange dwell times should be determined individually and adapted to the needs of the patient, with particular attention to phosphate clearance and ultrafiltration capacity. The evolution of residual kidney function and the availability of new, more physiologic, peritoneal dialysis fluids (PDFs) also influence the prescription process. An understanding of all of these principles is integral to the provision of clinically optimal PD.

Pathogenesis and treatment of peritoneal membrane failure

Peritoneal dialysis (PD) is a viable treatment option for end stage renal disease (ESRD) patients worldwide. PD may provide a survival advantages over hemodialysis (HD) in the early years of treatment. However, the benefits of PD are short-lived, as peritoneal membrane failure ensues in many patients, owing mainly to structural and functional changes in the peritoneal membrane from the use of conventional bio-incompatible PD solutions, which are hyperosmolar, acidic, have lactate buffer and contain high concentrations of glucose and glucose degradation products (GDPs). Current data suggest that chronic exposure of the peritoneum to contemporary PD fluids provokes activation of various inflammatory, fibrogenic and angiogenic cytokines, interplay of which leads to progressive peritoneal fibrosis, vasculopathy and neoangiogenesis. There is emerging evidence that peritoneal vascular changes are mainly responsible for increased solute transport and ultrafiltration failure in long-term PD. However, the precise pathophysiologic mechanisms initiating and propagating peritoneal fibrosis and angiogenesis remain elusive. The protection of the peritoneal membrane from long-term toxic and metabolic effects of high GDP-containing, conventional, glucose-based solutions is a prime objective to improve PD outcome. Recent development of new, more biocompatible, PD solutions should help to preserve peritoneal membrane function, promote ultrafiltration, improve nutritional status and, hopefully, preserve peritoneal membrane and improve overall PD outcomes. Elucidation of molecular mechanisms involved in the cellular responses leading to peritoneal fibrosis and angiogenesis spurs new therapeutic strategies that might protect the peritoneal membrane against the consequences of longstanding PD.

Advances in renal replacement therapy as a bridge to renal transplantation

While renal transplantation remains the most prevalent treatment for children with end-stage renal disease, the majority of children incident to ESRD receive dialytic therapy prior to receiving a renal allograft and 25% of children are still receiving dialytic therapy 36 months after achieving ESRD. The current review discusses the most recent advancements in both hemodialysis and PD therapies to provide optimal care for children as a bridge until renal transplantation. Areas covered include dialysis dose assessment, target dry weight assessment, vascular access and advancements in PD technology.

Peritoneal dialysis in infants

The need for maintenance dialysis for infants is rare, but peritoneal dialysis has been the modality of choice in cases of end-stage renal failure, for technical reasons. Problems include higher mortality rates and an inferior long-term outcome compared with that in older children. Also, no internationally accepted guidelines exist for dialysis in infants. Many children on maintenance peritoneal dialysis in Finland have congenital nephrotic syndrome of the Finnish type (NPHS1), and dialysis is started during infancy. In this commentary we discuss our practice of performing peritoneal dialysis in infants and experiences gathered from the literature.

[What is new in pediatric nephrology?]

Recent advances in the knowledge of physiology, genetics, imaging, and therapeutics have lead to novel practical approaches in paediatric nephrology. Many inherited syndromes have been revisited in order to identify precise renal diseases at the molecular level. In addition, a large number of epidemiological studies and clinical trials have allowed guidelines and recommendations to be provided for chronic and end-stage renal failure, urinary tract infection, glomerular diseases, etc.