Measurement of hydrostatic intraperitoneal pressure: a useful tool for the improvement of dialysis dose prescription

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.

Novel equations for estimating intraperitoneal pressure among peritoneal dialysis patients

Background

Increased intraperitoneal pressure (IPP) is associated with abdominal wall complications and technical failure in peritoneal dialysis (PD). Since the standard measurement of IPP is limited due to its cumbersome procedures, we aimed to develop and validate equations for estimating IPP.

Methods

We performed a cross-sectional study with a total of 200 prevalent PD patients who were divided into development and validation datasets after random sampling matched by body mass index. The IPPs were measured using the Durand method, with whole-body and abdominal anthropometry indices collected. Equations with 2.0-L and 1.5-L fill volumes were generated by stepwise linear regression modelling. The bias, accuracy and precision of the estimated IPP (eIPP) with 2-L and 1.5-L fill volumes were compared with actual IPPs by the Durand method. The eIPP for the 2-L fill volume was also compared with other existing equations.

Results

Two new equations incorporating waist circumference and height from the decubitus plane to mid-axillary line were generated. The eIPPs exhibited small biases in relation to the Durand method , with median differences of -0.24 cmH2O and -0.10 cmH2O for 2 L and 1.5 L, respectively. The precisions evaluated by the standard deviation of the absolute value of the differences were 2.59 cmH2O and 2.50 cmH2O, respectively. The accuracies evaluated by the value of the percentage of estimates that differed by >20% for the eIPP were 26% for 2.0 L and 27% for 1.5 L. Better bias, precision and accuracy were observed for the eIPP equation compared with other existing equations for the 2.0-L fill volume.

Conclusions

We provided two new equations developed from abdominal anthropometry indices to accurately estimate the IPP in the PD population.

Care of the pediatric patient on chronic peritoneal dialysis

Peritoneal dialysis is the most commonly prescribed dialysis modality for infants and young children with kidney failure worldwide. Provision of high-quality care for the pediatric patient on chronic peritoneal dialysis requires a multidisciplinary approach and a strong collaboration with the patient and their caregiver. This article not only reviews current recommendations and advances in the care of pediatric patients on peritoneal dialysis with a focus on the provision of high-quality care and improvement in outcomes, but it also draws attention to health care disparities that exist locally and globally.

Traduction des Recommandations de l'ISPD pour l'évaluation du dysfonctionnement de la membrane péritonéale chez l'adulte

Informations concernant cette traductionDans le cadre d’un accord de partenariat entre l’ISPD et le RDPLF, le RDPLF est le traducteur français officiel des recommandations de l’ISPD. La traduction ne donne lieu à aucune compensation financière de la part de chaque société et le RDPLF s’est engagé à traduire fidèlement le texte original sous la responsabilité de deux néphrologues connus pour leur expertise dans le domaine. Avant publication le texte a été soumis à l’accord de l’ISPD. La traduction est disponible sur le site de l’ISPD et dans le Bulletin de la Dialyse à Domicile.Le texte est, comme l’original, libremement téléchargeable sous licence copyright CC By 4.0https://creativecommons.org/licenses/by/4.0/Cette traduction est destinée à aider les professionnels de la communauté francophone à prendre connaissance des recommandations de l’ISPD dans leur langue maternelle. Toute référence dans un article doit se faire au texte original en accès libre :Peritoneal Dialysis International https://doi.org/10.1177/0896860820982218 Dans les articles rédigés pour des revues françaises, conserver la référence à la version originale anglaise ci dessus, mais ajouter «version française  https://doi.org/10.25796/bdd.v4i3.62673"»TraducteursDr Christian Verger, néphrologue, président du RDPLFRDPLF, 30 rue Sere Depoin, 95300 Pontoise – FranceProfesseur Max Dratwa, néphrologueHôpital Universitaire Brugmann – Bruxelles – Belgique

ISPD recommendations for the evaluation of peritoneal membrane dysfunction in adults: Classification, measurement, interpretation and rationale for intervention

Lay summary

Peritoneal dialysis (PD) uses the peritoneal membrane for dialysis. The peritoneal membrane is a thin layer of tissue that lines the abdomen. The lining is used as a filter to help remove extra fluid and poisonous waste from the blood. Everybody is unique. What is normal for one person’s membrane may be very different from another person’s. The kidney care team wants to provide each person with the best dialysis prescription for them and to do this they must evaluate the person’s peritoneal lining. Sometimes dialysis treatment itself can cause the membrane to change after some years. This means more assessments (evaluations) will be needed to determine whether the person’s peritoneal membrane has changed. Changes in the membrane may require changes to the dialysis prescription. This is needed to achieve the best dialysis outcomes. A key tool for these assessments is the peritoneal equilibration test (PET). It is a simple, standardized and reproducible tool. This tool is used to measure the peritoneal function soon after the start of dialysis. The goal is to understand how well the peritoneal membrane works at the start of dialysis. Later on in treatment, the PET helps to monitor changes in peritoneal function. If there are changes between assessments causing problems, the PET data may explain the cause of the dysfunction. This may be used to change the dialysis prescription to achieve the best outcomes. The most common problem with the peritoneal membrane occurs when fluid is not removed as well as it should be. This happens when toxins (poisons) in the blood cross the membrane more quickly than they should. This is referred to as a fast peritoneal solute transfer rate (PSTR). Since more efficient fluid removal is associated with better outcomes, developing a personal PD prescription based on the person’s PSTR is critically important. A less common problem happens when the membrane fails to work properly (also called membrane dysfunction) because the peritoneal membrane is less efficient, either at the start of treatment or developing after some years. If membrane dysfunction gets worse over time, then this is associated with progressive damage, scarring and thickening of the membrane. This problem can be identified through another change of the PET. It is called reduced ‘sodium dip’. Membrane dysfunction of this type is more difficult to treat and has many implications for the individual. If the damage is major, the person may need to stop PD. They would need to begin haemodialysis treatment (also spelled hemodialysis). This is a very important and emotional decision for individuals with kidney failure. Any decision that involves stopping PD therapy or transitioning to haemodialysis therapy should be made jointly between the clinical team, the person on dialysis and a caregiver, if requested. Although evidence is lacking about how often tests should be performed to determine peritoneal function, it seems reasonable to repeat them whenever there is difficulty in removing the amount of fluid necessary for maintaining the health and well-being of the individual. Whether routine evaluation of membrane function is associated with better outcomes has not been studied. Further research is needed to answer this important question as national policies in many parts of the world and the COVID-19 has placed a greater emphasis and new incentives encouraging the greater adoption of home dialysis therapies, especially PD. For Chinese and Spanish Translation of the Lay Summary, see Online Supplement Appendix 1.

Key recommendations

Guideline 1:

A pathophysiological taxonomy: A pathophysiological classification of membrane dysfunction, which provides mechanistic links to functional characteristics, should be used when prescribing individualized dialysis or when planning modality transfer (e.g. to automated peritoneal dialysis (PD) or haemodialysis) in the context of shared and informed decision-making with the person on PD, taking individual circumstances and treatment goals into account. (practice point)

Guideline 2a:

Identification of fast peritoneal solute transfer rate (PSTR): It is recommended that the PSTR is determined from a 4-h peritoneal equilibration test (PET), using either 2.5%/2.27% or 4.25%/3.86% dextrose/glucose concentration and creatinine as the index solute. (practice point) This should be done early in the course dialysis treatment (between 6 weeks and 12 weeks) (GRADE 1A) and subsequently when clinically indicated. (practice point)

Guideline 2b:

Clinical implications and mitigation of fast solute transfer: A faster PSTR is associated with lower survival on PD. (GRADE 1A) This risk is in part due to the lower ultrafiltration (UF) and increased net fluid reabsorption that occurs when the PSTR is above the average value. The resulting lower net UF can be avoided by shortening glucose-based exchanges, using a polyglucose solution (icodextrin), and/or prescribing higher glucose concentrations. (GRADE 1A) Compared to glucose, use of icodextrin can translate into improved fluid status and fewer episodes of fluid overload. (GRADE 1A) Use of automated PD and icodextrin may mitigate the mortality risk associated with fast PSTR. (practice point)

Guideline 3:

Recognizing low UF capacity: This is easy to measure and a valuable screening test. Insufficient UF should be suspected when either (a) the net UF from a 4-h PET is <400 ml (3.86% glucose/4.25% dextrose) or <100 ml (2.27% glucose /2.5% dextrose), (GRADE 1B) and/or (b) the daily UF is insufficient to maintain adequate fluid status. (practice point) Besides membrane dysfunction, low UF capacity can also result from mechanical problems, leaks or increased fluid absorption across the peritoneal membrane not explained by fast PSTR.

Guideline 4a:

Diagnosing intrinsic membrane dysfunction (manifesting as low osmotic conductance to glucose) as a cause of UF insufficiency: When insufficient UF is suspected, the 4-h PET should be supplemented by measurement of the sodium dip at 1 h using a 3.86% glucose/4.25% dextrose exchange for diagnostic purposes. A sodium dip ≤5 mmol/L and/or a sodium sieving ratio ≤0.03 at 1 h indicates UF insufficiency. (GRADE 2B)

Guideline 4b:

Clinical implications of intrinsic membrane dysfunction (de novo or acquired): in the absence of residual kidney function, this is likely to necessitate the use of hypertonic glucose exchanges and possible transfer to haemodialysis. Acquired membrane injury, especially in the context of prolonged time on treatment, should prompt discussions about the risk of encapsulating peritoneal sclerosis. (practice point)

Guideline 5:

Additional membrane function tests: measures of peritoneal protein loss, intraperitoneal pressure and more complex tests that estimate osmotic conductance and ‘lymphatic’ reabsorption are not recommended for routine clinical practice but remain valuable research methods. (practice point)

Guideline 6:

Socioeconomic considerations: When resource constraints prevent the use of routine tests, consideration of membrane function should still be part of the clinical management and may be inferred from the daily UF in response to the prescription. (practice point)

Adequacy of Peritoneal Dialysis in Children: Consider the Membrane for Optimal Prescription

The peritoneal dialysis (PD) prescription should be adequate before being optimal. The peritoneal membrane is a dynamic dialyzer: the surface area and the vascular area both have recruitment capacity.

At bedside, prescription is based mainly on tolerance of the prescribed fill volume, and therefore a too-small fill volume is often prescribed. A too-small fill volume may lead to a hyperpermeable exchange, with potentially enhanced morbidity—or even mortality—risks. Better understanding of the peritoneal membrane as a dynamic dialysis surface area allows for an individually adapted prescription, which is especially suitable for children on automated PD.

Fill volume should be scaled for body surface area (mL/m2) and, to avoid a hyperpermeable exchange, for a not-too-small amount. Fill volume enhancement should be conducted under clinical control and is best determined by intraperitoneal pressure measurement in centimeters of H2O. In children 2 years of age and older, a peak fill volume of 1400 – 1500 mL/m2 can be prescribed in terms of tolerance, efficiency, and peritoneal membrane recruitment.

Dwell times should be determined individually with respect to two opposing parameters:

• Short dwell times provide adequate small-solute clearance and maintain the crystalloid osmotic gradient (and, thereby, the ultrafiltration capacity).

• Long dwell times enhance phosphate clearance, but can lead to dialysate reabsorption.

The new PD fluids (that is, those free of glucose degradation products, with a neutral pH, and not exclusively lactate-buffered) appear to be the best choice both in terms of membrane recruitment and of preservation of peritoneal vascular hyperperfusion.

Identification of the Factors Associated With Intraperitoneal Pressure in ADPKD Patients Treated With Peritoneal Dialysis

Introduction

Peritoneal dialysis (PD) is reported to be underused in the autosomal dominant polycystic kidney disease (ADPKD) population because doctors fear technical failure caused by reduced abdominal space and high intraperitoneal pressure (IPP).

Methods

We designed a multicenter retrospective study to be carried out in 15 French centers recruiting 60 patients with ADPKD treated with PD to identify factors associated with IPP. Inclusion criteria were start of PD between 2010 and 2017, available tomodensitometry, and IPP measurement in the first year of dialysis. The clinical and radiological data for each patient were reviewed by the same operator. Total kidney volume (TKV), liver volume, and the volume of the abdominal cavity were measured using contouring.

Results

TKV and the volume of the abdominal cavity in women and men were, respectively, 2397 ml versus 3758 ml and 9402 ml versus 12,920 ml. In the univariate analysis, IPP was significantly and positively associated with body surface area (P = 0.0024), body mass index (BMI) (P < 0.0001), the volume of the abdominal cavity (P = 0.0005), and the volume of the dialysate infused in the peritoneal cavity (IPV) (P = 0.0108). In the multivariate analysis, only BMI was still significantly associated with IPP (P = 0.0004)

Conclusions

Our results identified BMI as the main factor linked to IPP in patients with ADPKD. Despite a reliable assessment of the volume of their organs we did not find any correlation between liver and kidney volumes and IPP. To our knowledge, this is the first study designed to identify factors associated with IPP in patients with ADPKD on PD.

Application of Ion Mobility Spectrometry for Permeability Studies of Organic Substances through Polymeric Materials

Drift tube ion mobility spectrometers (DT IMS) allow the concentration of different organic compounds to be measured. This gives the opportunity to use these detectors in measuring the penetration of various substances through polymer membranes. Permeation measurements of two substances (2-heptanone and dimethyl methylphosphonate (DMMP)) through a cylindrical silicone rubber membrane were carried out. The membrane separated the aqueous solution from the air. The analyte was introduced into water, and then its concentration in air on the opposite side of the membrane was recorded. Based on the dynamics of detector signal changes, the diffusion coefficients for both tested substances were determined. Determination of permeability coefficients was based on precise quantitative measurements, which took into account the non-linearity of the detector characteristics and the effect of water on detection sensitivity. The analysis of measurement results was based on a mathematical description of diffusion process.

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.

The Influence of Peritoneal Surface Area on Dialysis Adequacy

In children, the prescription of peritoneal dialysis is based mainly on the choice of the peritoneal dialysis fluid, the intraperitoneal fill volume (mL/m2 body surface area (BSA)], and the contact time. The working mode of the peritoneal membrane as a dialysis membrane is more related to a dynamic complex structure than to a static hemodialyzer. Thus, the peritoneal surface area impacts on dialysis adequacy. In fact, the peritoneal surface area may be viewed as composed of three exchange entities: the anatomic area, the contact area, and the vascular area.

First, in infants, the anatomic area appears to be twofold larger than in adults when expressed per kilogram body weight. On the other hand, the anatomic area becomes independent of age when expressed per square meter BSA. Therefore, scaling of the intraperitoneal fill volume by BSA (m2) is necessary to prevent a too low ratio of fill volume to exchange area, which would result in a functional “hyperpermeable” peritoneal exchange. Second, the contact area, also called the wetted membrane, is only a portion of the anatomic area, representing 30% to 60% of this area in humans, as measured by computed tomography. Both posture and fill volume may affect the extent of recruitment of contact area. Finally, the vascular area is influenced by the availability of both the anatomic area and the recruited contact area. This surface is governed essentially by both peritoneal vascular perfusion, represented by the mesenteric vascular flow and, hence, by the number of perfused capillaries available for exchange. This vascular area is dynamically affected by different factors, such as composition of the peritoneal fluid, the fill volume, and the production of inflammatory agents.

Peritoneal dialysis fluids that will be developed in the future for children should allow an optimization of the fill volume owing to a better tolerance in terms of lower achieved intraperitoneal pressure for a given fill volume. Moreover, future peritoneal dialysis fluids should protect the peritoneal membrane from hyperperfusion (lower glucose degradation products).

Acute Central Hemodynamic Effects of a Volume Exchange in Peritoneal Dialysis

Background

Although peritoneal dialysis is considered to offer more hemodynamic stability than hemodialysis, the acute hemodynamic effects of peritoneal dialysis have only been investigated scarcely. The present study assesses the central hemodynamic impact of volume infusion using pH-adjusted icodextrin, thus avoiding interference of glucose, pH, and osmolarity.

Methods

Patients were randomized to 3 different starting volumes (A: 1000 mL, B: 1500 mL, and C: 2500 mL) of icodextrin, followed by addition (A and B) or drainage (C) of 200 mL every 10 minutes for 50 minutes. Local carotid systolic blood pressure (BP; as a surrogate for central BP), augmentation index, and augmentation pressure were measured by applanation tonometry before and after infusion of the starting volumes and after each volume change.

Results

We included 13 patients (median age 57 years). Baseline brachial BP was 126/77 mmHg. After infusion of the starting volume, carotid systolic BP and augmentation pressure increased by 4.7 mmHg ( p = 0.006) and 3.1 mmHg ( p = 0.015). Augmentation index increased by 5.7% ( p = 0.04) and heart rate decreased by 2.6/minute ( p = 0.006). Intraperitoneal pressure increased by 2.3 cm H2O ( p = 0.03). No additional hemodynamic changes except for a rise in diastolic BP with increasing volume ( p = 0.004) were observed after subsequent addition or removal of volumes.

Conclusions

Infusion of peritoneal dialysis fluids causes an acute increase in carotid systolic B P, followed by a progressive rise in diastolic BP. These effects persist until complete drainage of the abdomen and may be due to an enhanced preload, resulting from intraperitoneal venous compression, and/or increased wave reflection.

Clinical relevance of marginal factors on ultrafiltration in peritoneal dialysis

BACKGROUND

Ultrafiltration (UF) in peritoneal dialysis (PD) is mainly driven by the osmotic gradient and peritoneal permeability, but other factors-such as intraperitoneal pressure (IPP)-also have an influence.

METHODS

To assess the clinical relevance of these marginal factors, we studied 41 unselected PD patients undergoing two consecutive 2 h, 2.27% glucose exchanges, first with 2.5 L and then with 1.5 L.

RESULTS

IPP, higher in the 2.5 L exchange, had a wide interpatient range, was higher in obese and polycystic patients and their increase with infusion volume was higher for women regardless of body size. UF with 2.5 L correlated inversely with IPP and was higher for patients with polycystosis or hernias, while for 1.5 L we found no significant correlations. The effluent had higher glucose and osmolarity in the 2.5 L exchange than in the 1.5 L one, similar for both sexes. In spite of this stronger osmotic gradient, only 21 patients had more UF in the 2.5 L exchange, with differences up to 240 mL. The other 20 patients had more UF in the 1.5 L exchange, with stronger differences (up to 800 mL, and more than 240 mL for 9 patients). The second group, with similar effluent osmolarity and peritoneal equilibration test (PET) parameters than the first, has higher IPP and preponderance of men. The sex influence is so intense that men decreased average UF with 2.5 L with respect to 1.5 L, while women increased it.

CONCLUSIONS

With 2.27% glucose, sex and IPP-modulated by obesity, polycystosis, hernias, and intraperitoneal volume-significantly affect UF in clinical settings and might be useful for its management.

Hypertension in Pediatric Dialysis Patients: Etiology, Evaluation, and Management

PURPOSE OF REVIEW

Review epidemiology, pathophysiology, and management of hypertension in the pediatric dialysis population.

RECENT FINDINGS

Interdialytic blood pressure measurement, especially with ambulatory blood pressure monitoring, is the gold standard to assess for hypertension. Tools to assess dry weight aid in achievement of euvolemia, the primary therapy for management of hypertension. Persistent hypertension should be treated with antihypertensive medications and potentially with native nephrectomies. Cardiovascular disease continues to be the primary cause of morbidity and mortality in the dialysis population with hypertension as an important modifiable factor. Achievement on dry weight and limiting both aggressiveness of interdialytic weight gain and ultrafiltration rate underlie the best approach. Tools to assess volume status beyond clinical assessment have shown promise in achieving euvolemia. When hypertension persists despite achievement of euvolemia, antihypertensive medications may be required and in some cases native nephrectomies. Future studies in children are needed to determine the best antihypertensive class and ideal rate of ultrafiltration on hemodialysis towards achievement of normotension and reduction of cardiovascular risk.

Blood pressure management in children on dialysis

Hypertension is a leading cause of cardiovascular complications in children on dialysis. Volume overload and activation of the renin-angiotensin-aldosterone system play a major role in the pathophysiology of hypertension. The first step in managing blood pressure (BP) is the careful assessment of ambulatory BP monitoring. Volume control is essential and should start with the accurate identification of dry weight, based on a comprehensive assessment, including bioimpedance analysis and intradialytic blood volume monitoring (BVM). Reduction of interdialytic weight gain (IDWG) is critical, as higher IDWG is associated with a worse left ventricular mass index and poorer BP control: it can be obtained by means of salt restriction, reduced fluid intake, and optimized sodium removal in dialysis. Optimization of peritoneal dialysis and intensified hemodialysis or hemodiafiltration have been shown to improve both fluid and sodium management, leading to better BP levels. Studies comparing different antihypertensive agents in children are lacking. The pharmacokinetic properties of each drug should be considered. At present, BP control remains suboptimal in many patients and efforts are needed to improve the long-term outcomes of children on dialysis.

Intraperitoneal pressure in peritoneal dialysis

The measure of intraperitoneal pressure in peritoneal dialysis is easy and provides clear therapeutic benefits. However it is measured only rarely in adult peritoneal dialysis units. This review aims to disseminate the usefulness of measuring intraperitoneal pressure. This measurement is performed in supine before initiating the drain of a manual exchange with "Y" system, by raising the drain bag and measuring from the mid-axillary line the height of the liquid column that rises from the patient. With typical values of 10-16 cmH₂O, intraperitoneal pressure should never exceed 18 cmH₂O. With basal values that depend on body mass index, it increases 1-3 cmH₂O/L of intraperitoneal volume, and varies with posture and physical activity. Its increase causes discomfort, sleep and breathing disturbances, and has been linked to the occurrence of leaks, hernias, hydrothorax, gastro-esophageal reflux and enteric peritonitis. Less known and valued is its ability to decrease the effectiveness of dialysis significantly counteracting ultrafiltration and decreasing solute clearance to a smaller degree. Because of its easy measurement and potential utility, should be monitored in case of ultrafiltration failure to rule out its eventual contribution in some patients. Although not yet mentioned in the clinical practice guidelines for PD, its clear benefits justify its inclusion among the periodic measurements to consider for prescribing and monitoring peritoneal dialysis.

Peritoneal dialysis for the management of pediatric patients with acute kidney injury

Renal replacement therapy (RRT) is the most important supportive measure used in the management of acute kidney injury (AKI). Peritoneal dialysis (PD) is a safe, simple and inexpensive procedure and has been used in pediatric AKI patients, ranging from neonates to adolescents. It is the modality of choice for RRT in developing countries with cost constraints and limited resources. However, its use has declined with the availability of newer types of extracorporeal modalities for RRT in the developed world. Much controversy exists regarding the dosing and adequacy of PD in the management of AKI. Data in infants and children have shown that PD can provide adequate clearance, ultrafiltration and correction of metabolic abnormalities even in those who are critically ill. Although there are no prospective studies in children, data from retrospective studies reveal no differences in mortality rates between different modalities of RRT. In this review, we discuss the advantages and limitations of PD, indications for acute PD, strategies to improve the efficiency of acute PD and outcomes of PD in children with AKI.

Should sodium removal in peritoneal dialysis be estimated from the ultrafiltration volume?

In peritoneal dialysis (PD), ultrafiltration (UF) volume is the sum of solute-free- and solute-coupled-water removal, a dynamic process throughout the entire dwell exerted via aquaporin-1 (AQP1) and small pores, respectively. Determination of sodium sieving is used as a parameter for AQP1 function analysis, while coupled water removal is essential for adequate sodium and water balance and thus blood pressure control. The diffusive capacity of glucose via the small pores determines the dynamic crystalloid osmotic gradient. The osmotic conductance, i.e., milliliter of UF per gram of glucose absorbed, quantifies cooperation between small-pores and AQP1 channels. In continuous ambulatory peritoneal dialysis, with dwell times beyond glucose-induced sodium-sieving effects, approximate dialytic sodium removal (DSR) may be estimated from the UF volume (in average 100 mmol Na/L UF), while DSR is lower, with shorter cycle times, in automated PD (APD); therefore, effluent sodium concentrations should be measured. Applying dialysis mechanics, i.e., varying dwell time and dwell volume-as proposed in adapted APD to the PD prescription-may provide unmatched high DSR relative to UF volume, findings which are not sufficiently explained by the three-pore model of PD. Overall DSR should therefore be measured rather than estimated from UF volume.

[Peritoneal equilibration test: Conventional versus adapted. Preliminary study]

Conventional automated peritoneal dialysis (APD) is prescribed as a repetition of cycles with the same dwell time and the same fill volume. Water and sodium balance remains a common problem among patients on peritoneal dialysis. More recently, adapted automated peritoneal dialysis was described, as a combination of short dwells with a low volume, in order to enhance ultrafiltration, followed by long dwells with a large fill volume to favor solute removal. We performed a preliminary crossover study on 4 patients. The total amount of dialysate was the same, i.e. 2L/m² as well as the total duration of the test, i.e. 150 minutes. The conventional test was made with two identical cycles, each cycle had a fill volume of 1L/m² and a duration of 75 minutes, while the adapted test was performed with one short cycle, i.e. 30 minutes with a low fill volume, i.e. 0.6L/m², followed by a long cycle, i.e. 120 minutes, with a large fill volume, i.e. 1.4L/m². Sodium extraction was improved by 29.3mmol/m² (169%) in the adapted test in comparison to the conventional test. Ultrafiltration was enhanced by 159mL/m² (128%) in the adapted test compared to the conventional one. Glucose absorption was decreased by 35% in the adapted test in comparison to the conventional test and osmotic conductance was also improved. In conclusion, adapted dialysis may allow for a better volume and sodium balance, since we observed an improvement in sodium extraction and ultrafiltration. This pre-study authorizes an improvement of the European Pediatric Study's protocol on Adapted APD, already started and which will continue in the next months.

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.

The neglected role of abdominal compliance in organ-organ interactions

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency medicine 2016. Other selected articles can be found online at http://www.biomedcentral.com/collections/annualupdate2016. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

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.

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.

Integration of inspiratory and expiratory intra-abdominal pressure: a novel concept looking at mean intra-abdominal pressure

BACKGROUND

The intra-abdominal pressure (IAP) is an important clinical parameter that can significantly change during respiration. Currently, IAP is recorded at end-expiration (IAPee), while continuous IAP changes during respiration (ΔIAP) are ignored. Herein, a novel concept of considering continuous IAP changes during respiration is presented.

METHODS

Based on the geometric mean of the IAP waveform (MIAP), a mathematical model was developed for calculating respiratory-integrated MIAP (i.e. MIAPri=IAPee+i⋅ΔIAP), where 'i' is the decimal fraction of the inspiratory time, and where ΔIAP can be calculated as the difference between the IAP at end-inspiration (IAPei) minus IAPee. The effect of various parameters on IAPee and MIAPri was evaluated with a mathematical model and validated afterwards in six mechanically ventilated patients. The MIAP of the patients was also calculated using a CiMON monitor (Pulsion Medical Systems, Munich, Germany). Several other parameters were recorded and used for comparison.

RESULTS

The human study confirmed the mathematical modelling, showing that MIAPri correlates well with MIAP (R2 = 0.99); MIAPri was significantly higher than IAPee under all conditions that were used to examine the effects of changes in IAPee, the inspiratory/expiratory (I:E) ratio, and ΔIAP (P <0.001). Univariate Pearson regression analysis showed significant correlations between MIAPri and IAPei (R = 0.99), IAPee (R = 0.99), and ΔIAP (R = 0.78) (P <0.001); multivariate regression analysis confirmed that IAPee (mainly affected by the level of positive end-expiratory pressure, PEEP), ΔIAP, and the I:E ratio are independent variables (P <0.001) determining MIAP. According to the results of a regression analysis, MIAP can also be calculated asMIAP=-0.3+IAPee+0.4⋅ΔIAP+0.5⋅IE.

CONCLUSIONS

We believe that the novel concept of MIAP is a better representation of IAP (especially in mechanically ventilated patients) because MIAP takes into account the IAP changes during respiration. The MIAP can be estimated by the MIAPri equation. Since MIAPri is almost always greater than the classic IAP, this may have implications on end-organ function during intra-abdominal hypertension. Further clinical studies are necessary to evaluate the physiological effects of MIAP.

Comparative Role of PET and Kt/V Determination in Pediatric Chronic Peritoneal Dialysis

Introduction

Nutritional state and growth are considered as prognostic markers of chronic peritoneal dialysis (PD) adequacy in pediatric patients. The euvolemia, blood pressure control, and metabolic and electrolytic equilibrium are parameters to be achieved by PD treatment.

Objective

To describe the chronic PD prescription parameters of a cohort of pediatric patients and to compare the obtained hemodynamic, antrophometric and adequacy results with those suggested by the literature.

Methods

Retrospective analysis based on clinical records evaluation of 30 pediatric patients undergoing PD for more than 6 months from January 1998 to May 2005.

Results

In the present study, 17/30 (56.7%) were boys. Chronic kidney disease was secondary to uropathy in 66.7% of the cases. The infusion volume was > 1,000 ml/m2 in 9 patients. The peritoneal membrane was characterized as high (27.8%), high-average (33.3%), low-average (22.2%) and low transporter (16.7%). The weekly urea Kt/V was > 2.1 in all the evaluated patients. Blood pressure parameters above the 95th percentile despite the use of antihypertensive medication were observed in 5/30 patients, four of whom with CKD secondary to glomerulopathy. The initial and final Body Mass Index and weight for height ratio were preserved in 83.3% (25/30) patients.

Conclusion

Elevated indexes of small solutes removal are easily attained in pediatric PD patients and do not imply optimal clinical management do not imply optimal climanagement.

Peritoneal dialysis in children with end-stage renal disease

Peritoneal dialysis is the preferred chronic dialysis modality for most children owing to its almost universal applicability and superior compatibility with lifestyle over other modalities. Although technological advances and increasing clinical experience have impacted favorably on patient and technique survival, clinical research in pediatric peritoneal dialysis has been hampered by the low incidence of end-stage renal disease (ESRD) in the pediatric population. To overcome this limitation, several international registries have emerged in the past few years to complement other long-standing registries, which together have provided useful information regarding technique-specific complications and comorbidities associated with ESRD in children undergoing chronic peritoneal dialysis. In this Review, we summarize the most relevant findings from these studies, highlighting the substantial variation in patient conditions, peritoneal dialysis practices and management of comorbidities encountered in different parts of the world.

Peritoneal dialysis in infants: the experience of the Italian Registry of Paediatric Chronic Dialysis

BACKGROUND

Although chronic peritoneal dialysis (CPD) is considered the replacement therapy of choice for infants with end-stage renal failure, many questions persist about treatment risks and outcomes.

METHODS

We present data on 84 infants who started CPD at <1 year of age; these patients represent 12% of the total population of the Italian Registry of Paediatric Chronic Dialysis. We analysed patient records from all children consecutively treated with CPD between 1995 and 2007 in Italy. Growth data analysis was performed only in infants with complete auxological parameters at 0, 6 and 12 months of follow-up.

RESULTS

Median age at the start of CPD was 6.9 months, weight was 6.1 kg and length 63.6 cm. In one-half of the study population diagnosis leading to renal failure was congenital nephrouropathy. Twenty-eight per cent of the children had at least one pre-existing comorbidity. The mean height standard deviation score was -1.65 at the start of CPD, -1.82 after 12 months and -1.53 after 24 months. Catch-up growth was documented in 50% of patients during dialysis. A positive correlation was observed between longitudinal growth and both exchange volume (R(2) = 0.36) and dialysis session length (R(2) = 0.35), while a negative association was found with the number of peritonitis cases (P = 0.003). Peritonitis incidence was 1:20.7 episode:CPD-months (1:28.3 in the older children from the same registry) and was significantly higher in children with oligoanuria (1:15.5 episode:CPD-months) compared to infants with residual renal function (1:37.4 episode:CPD-months). Catheter survival rate was 70% at 12 months and 51% at 24 months. Catheter-related complications were similar in infants and older children (1:20.5 versus 1:19.8 episode:CPD-months), while clinical complications were more frequent in children under 1 year of age (1:18.3 versus 1:25.2 episode:CPD-months; P < 0.05). During the follow-up period, 33 patients were transplanted (39.3%), 18 were shifted to haemodialysis (21.4%) and 8 died (9.5%). The mortality rate was 4-fold greater than in older children (2.3%).

CONCLUSIONS

Our data confirm that infants on CPD represent a high-risk group; however, our experience demonstrated that growth was acceptable and a large portion was successfully transplanted. Increased efforts should be aimed at optimizing dialysis efficiency and preventing peritonitis. The higher mortality rate in infants was largely caused by comorbidities.

Peritoneal dialysis tailored to pediatric needs

Consideration of specific pediatric aspects is essential to achieve adequate peritoneal dialysis (PD) treatment in children. These are first of all the rapid growth, in particular during infancy and puberty, which must be accompanied by a positive calcium balance, and the age dependent changes in body composition. The high total body water content and the high ultrafiltration rates required in anuric infants for adequate nutrition predispose to overshooting convective sodium losses and severe hypotension. Tissue fragility and rapid increases in intraabdominal fat mass predispose to hernia and dialysate leaks. Peritoneal equilibration tests should repeatedly been performed to optimize individual dwell time. Intraperitoneal pressure measurements give an objective measure of intraperitoneal filling, which allow for an optimized dwell volume, that is, increased dialysis efficiency without increasing the risk of hernias, leaks, and retrofiltration. We present the concept of adapted PD, that is, the combination of short dwells with low fill volume to promote ultrafiltration and long dwells with a high fill volume to improve purification within one PD session. The use of PD solutions with low glucose degradation product content is recommended in children, but unfortunately still not feasible in many countries.

The beneficial influence on the effectiveness of automated peritoneal dialysis of varying the dwell time (short/long) and fill volume (small/large): a randomized controlled trial

BACKGROUND

It is well known that the efficiency of peritoneal dialysis (PD) varies with the duration of the dwell and with the prescribed fill volume. Automated PD (APD) is classically given as a series of recurrent exchanges, each having the same dwell time and fill volume-that is, conventional APD (APD-C). We propose a new way of giving PD, using a modified version of APD-C. This method first uses a short dwell time with a small fill volume to promote ultrafiltration (UF) and subsequently uses a longer dwell time and a larger fill volume to promote removal of uremic toxins from the blood. We use the term "adapted APD" (APD-A) to describe this modified form of PD.

METHODS

We designed a multicenter prospective randomized crossover trial to assess the impact of APD-A in comparison with APD-C on the efficacy of dialysis. The parameters investigated were overnight UF; weekly peritoneal Kt/V(urea); weekly peritoneal creatinine clearance corrected to 1.73 m(2) body surface area (K(creat)); and phosphate (PDR) and sodium dialytic removal (SDR) in millimoles per session, corrected for glucose absorption, which provides an estimate of metabolic cost. Blood pressure was also regularly monitored. Initially, 25 patients were identified for inclusion in the study. There were 6 withdrawals in total: 2 at enrolment, 1 at day 75 (transplantation), 2 at day 30 (catheter dysfunction), and 1 for drainage alarms. All patients received the same duration of overnight APD, using the same total volume of dialysate, with the same 1.5% glucose, lactate-buffered dialysate (Balance: Fresenius Medical Care, Bad Homburg, Germany).

RESULTS

Tolerance was good. Compared with APD-C, APD-A resulted in a significant enhancement of Kt/V(urea), K(creat), and PDR. The metabolic cost, in terms of glucose absorption, required to achieve dialytic capacity for urea, creatinine, and phosphate blood purification was significantly lower for APD-A than for APD-C, and UF increased during APD-A. With APD-A, each gram of glucose absorbed contributed to 18.25 ± 15.82 mL UF; in APD-C, each gram of glucose absorbed contributed to 15.79 ± 11.24 mL UF. However, that difference was not found to be significant (p=0.1218). The SDR was significantly higher with APD-A than with APD-C: 35.23 ± 52.00 mmol and 18.35 ± 48.68 mmol per session respectively (p<0.01). The mean blood pressure recorded at the end of each PD period (on day 45) was significantly lower when patients received APD-A than when they received APD-C.

CONCLUSIONS

Our study provides evidence that, compared with the uniform dwell times and fill volumes used throughout an APD-C dialysis session, the varying dwell times and fill volumes as described for an APD-A dialysis session result in improved dialysis efficiency in terms of UF, Kt/V(urea), K(creat), PDR, and SDR. Those results were achieved without incurring any extra financial costs and with a reduction in the metabolic cost (assessed using glucose absorption).

Relationship between drain volume/fill volume ratio and clinical outcomes associated with overfill complaints in peritoneal dialysis patients

BACKGROUND

To better understand the spectrum of overfill reports and their corresponding clinical severity and etiology, we conducted a review of overfill reports from the Manufacturer and User Facility Device Experience (MAUDE) database, which is within the Food and Drug Administration (FDA) Web site (www.fda.gov).

METHOD

We searched the MAUDE database for events related to overfill reports between 1 January 1995 and 31 December 2008 and recorded drain volume (DV)/fill volume (FV), or DV/FV, and clinical symptoms and signs associated with the overfill report.

RESULTS

Among 462 MAUDE reports with a possible overfill event, 440 reports (95.2%) with a confirmed overfill event contained sufficient information to ascertain the clinical severity of the event. The number of reports with a clinical severity rating of minor, moderate, major, or death was 331, 71, 28, and 10, respectively. The median (range) DV/FV for a subgroup of 292 reports with a clinical severity rating of minor, moderate, major, or death was 1.63 (1.06 - 4.29), 1.71 (1.08 - 5.87), 2.14(1.64 - 2.61), and 2.50 (2.28 - 3.33), respectively. Insufficient drain accounted for a majority of overfill reports.

CONCLUSION

Our analysis of reports from the MAUDE database suggests an association between DV/FV and clinical severity of the reported overfill event, as well as significant patient-to-patient variability with respect to intraperitoneal volume tolerance.

A reference equation for objectively adjusting dwell volume to obtain more ultrafiltration in daily practice of peritoneal dialysis

OBJECTIVES

Few studies mention how to objectively adjust peritoneal dialysis (PD) dwell volume for adult continuous ambulatory peritoneal dialysis (CAPD) patients. We proposed a reference equation composed of parameters from the peritoneal equilibrium test (PET) for adjusting daily dialysate dwell volume to obtain more ultrafiltration volume. Better fluid control could reduce more fluid overload-related complications.

DESIGN

We used body mass index, waist circumference, intraperitoneal pressure, and other parameters from peritoneal equilibrium test to compose a reference equation for fine-tuning daily dwell volume.

PATIENTS AND SETTING

Eighty-eight PD patients in one center with laboratory data collected during half-yearly PET evaluations were enrolled. Instilled dialysate was composed of 2.57% glucose PD fluid, either 1500 ml or 2000 ml in volume. In addition to other demographic data, intraperitoneal pressure (IPP) was also measured twice in the supine position four hours apart. We applied statistical multivariate techniques of discrimination analysis and logistic regression to verify the most feasible and optimal formula to determine infill volumes for patients.

RESULTS

We determined a novel formula for calculating daily dialysate dwell volume, Z: Z = (0.523 x waist circumference) + (0.852 x body mass index), derived from rotating axes to obtain an accurate prediction rate of 80.68% using the multivariate approach.

CONCLUSION

The novel formula used objective, real-time parameters for determining appropriate dwell volumes for PD patients to optimize maximal ultrafiltration volumes and reduce subjective abdominal discomfort. The novel formula makes frequent adjustment of daily dwell volume by physicians or patients easy to calculate.

Effect of Peritoneal Dialysis on Abdominal Circumference

Background

Peritoneal dialysis (PD) is probably underused because of fears concerning the body image of patients. For the purposes of providing exact information for patients when choosing between PD and hemodialysis, we studied the extent of increase in waist circumference by infusing dialysate.

Methods

The abdominal circumference of 44 PD patients was measured before and after infusion of dialysate. The change in circumference was compared to body mass index (BMI) and length of the abdominal cavity, defined by the distance between the processus xiphoideus and the os pubis.

Results

Mean abdominal circumferences at the umbilicus and the iliac crest increased from 92.6 ± 10.1 to 95.5 ± 10.0 cm and from 95.2 ± 8.5 to 96.2 ± 6.3 cm, respectively, when dialysate was infused ( p value for both < 0.01). A dialysate volume of 2000 mL increased the circumference only slightly more than the increase seen with 1500 mL. The change in circumference was not correlated with the circumference before the infusion, BMI, height of the patient, or length of the abdominal cavity.

Conclusions

This study shows that normal PD fill volumes increase the waist circumference only a little. This finding should ease the patient's presumption of PD changing the body image.

Normal growth and intravascular volume status with good metabolic control during peritoneal dialysis in infancy

The most demanding patient population on peritoneal dialysis (PD) consists of children under 2 years of age. Their growth is inferior to that of older children and maintaining euvolemia is difficult, especially in anuric patients. In this prospective study reported here, we enrolled 21 patients <2 years of age (mean 0.59 years) at onset of PD and monitored their uremia parameters and evaluated their nutrition. Since no good instrument currently exists for estimating intravascular volume status, we used traditional blood pressure measurements, echocardiography, and N-terminal atrial natriuretic peptide measurements. Growth was compared with midparental height. Metabolic control was good. Long-term hypertension was seen in 43% of the patients, but left ventricular hypertrophy decreased during the study period. Mean weekly urea Kt/V was 3.38 +/- 0.66 and creatinine clearance was 49 +/- 20 L/week per 1.73 m(2). Catch-up growth was documented in 57% of the patients during PD. However, these children did not attain their midparental height at the end of PD at a mean age of 1.71 years. Although favorable metabolic control and good growth were achieved during PD, these children lagged in term of their midparental height. We conclude that several instruments are needed for determining the management of intravascular volume status and that the control of calcium-phosphorus status is demanding.

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.

Selection of modalities, prescription, and technical issues in children on peritoneal dialysis

Peritoneal dialysis (PD) is widely employed as a dialytic therapy for uraemic children, especially in its automated form (APD), that is associated with less burden of care on patient and family than continuous ambulatory PD. Since APD offers a wide range of treatment options, based on intermittent and continuous regimens, prescription can be individualized according to patient's age, body size, residual renal function, nutritional intake, and growth-related metabolic needs. Transport capacity of the peritoneal membrane of each individual patient should be assessed, and regularly monitored, by means of standardized peritoneal function tests validated in pediatric patients. To ensure maximum recruitment of peritoneal exchange area, fill volume should be scaled to body surface area and adapted to each patient, according to clinical tolerance and intraperitoneal pressure. PD solutions should be employed according to their biocompatibility and potential ultrafiltration capacity; new pH-neutral, glucose-free solutions can be used in an integrated way in separate dwells, or by appropriately mixing during the same dialytic session. Kinetic modelling software programs may help in the tailoring of PD prescription to individual patients' characteristics and needs. Owing to advances in the technology of new APD machines, greater programming flexibility, memorized delivery control, and tele-dialysis are currently possible.

Dialysate leakage into pericardium in an infant on long-term peritoneal dialysis

We report on a 2-year-old boy on automated peritoneal dialysis (PD) with a history of multiple hernias and dialysate leaks who developed pericardial effusion. Magnetic resonance imaging (MRI) demonstrated a peritoneo-pericardial fistula. Dialysis had to be discontinued, since head-down tilt reproducibly induced significant hypotension. In PD patients with pericardial effusion a peritoneo-pericardial leak should be considered.

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.

How to Increase Adequacy of Peritoneal Dialysis in Children?

Since children on dialysis are treated most often with nightly intermittent peritoneal dialysis, adequacy of dialysis is determined by the number and duration of cycles, the volume of the dialysis fluid applied, and the choice of dialysis solution. The number and duration of cycles are dependent on the maximal acceptable duration of night rest and the permeability properties of the peritoneal membrane. The latter can be established by performance of a peritoneal equilibration test. The volume used should be about 1200 mL/m2 body surface area, and intraperitoneal pressure should be between 5 and 15 cm H2O. The dialysis solution administered should have a glucose concentration as low as possible, and an icodextrin daytime dwell may be considered.

Effect of peritoneal dialysis fluid composition on peritoneal area available for exchange in children

BACKGROUND

Although conventional peritoneal dialysis fluids (PDFs), such as Dianeal, are non-physiological in composition, new PDFs including Physioneal have a more neutral pH, are at least partially buffered with bicarbonate and, most importantly, contain low concentrations of glucose degradation products (GDPs).

METHODS

To evaluate the impact of new PDFs in childcare, we performed a comparative crossover study with Dianeal and Physioneal. We examined both intraperitoneal pressure (IPP), which partly reflects pain induction, and the total pore area available for exchange, which indicates the number of capillaries perfused in the peritoneal membrane at any given moment and therefore partly reflects peritoneal dialysis capacity. The IPP was determined after inflow of 1000 ml/m(2) body surface area (BSA) of dialysate (intraperitoneal volume; IPV). The steady-state unrestricted area over diffusion distance (A(0)/ triangle up x, in cm(2)/cm per 1.73 m(2) BSA) was calculated from the three-pore theory. Six children were enrolled in the study. On the first day, two consecutive peritoneal equilibration tests of 90 min each were performed using first Dianeal and then Physioneal. On the second study day, the procedure was repeated with the fluids given in the opposite order.

RESULTS

The mean IPP normalized to IPV (ml/m(2)) was significantly higher for Dianeal (9.5 +/- 0.9 cm/1000 ml/m(2)) than for Physioneal (7.9 +/- 1.2 cm/1000 ml/m(2), P < 0.01). The mean A(0)/ triangle up x was 17 +/- 4% larger with Dianeal (36 095 +/- 2009 cm(2)/cm per 1.73 m(2)) than with Physioneal (31 780 +/- 2185 cm(2)/cm per 1.73 m(2), P < 0.001; based on 24 data pairs).

CONCLUSIONS

These pilot study results suggest a higher biocompatibility for Physioneal than for Dianeal. Less inflow pain associated with Physioneal induced a lower IPP reflecting enhanced fill volume tolerance, and the lower A(0)/ triangle up x reflected less capillary recruitment. Taken together, these results suggest that the new more biocompatible PDFs will improve peritoneal dialysis therapy, although this conclusion will require verification in extended clinical trials.

Renal replacement therapy for acute renal failure in children: European guidelines

Acute renal failure (ARF) is uncommon in childhood and there is little consensus on the appropriate treatment modality when renal replacement therapy is required. Members of the European Pediatric Peritoneal Dialysis Working Group have produced the following guidelines in collaboration with nursing staff. Good practice requires early discussion of patients with ARF with pediatric nephrology staff and transfer for investigation and management in those with rapidly deteriorating renal function. Patients with ARF as part of multi-organ failure will be cared for in pediatric intensive care units where there should be access to pediatric nephrology support and advice. The choice of dialysis therapy will therefore depend upon the clinical circumstances, location of the patient, and expertise available. Peritoneal dialysis has generally been the preferred therapy for isolated failure of the kidney and is universally available. Intermittent hemodialysis is frequently used in renal units where nursing expertise is available and hemofiltration is increasingly employed in the intensive care situation. Practical guidelines for and the complications of each therapy are discussed.