Transcapillary ultrafiltration and peritoneal equilibration test in pediatric patients

The usefulness of the peritoneal equilibration test (PET) in children is unknown. The relationship between transcapillary ultrafiltration and PET was investigated in order to evaluate the usefulness of PET in children. PET was performed on 14 patients undergoing peritoneal dialysis. Their age and bodyweight ranged from 3.8 to 23.6 years and 10.2 to 55.8 kg, respectively. The patients were divided into two groups according to bodyweight; group A patients weighed ≤ 40 kg (n = 7) and group B patients weighed > 40 kg (n = 7). There was no significant difference in the mean infusion volume per bodyweight between the two groups, but the mean infusion volume per body surface area was smaller in group A than in group B. Group A showed a more rapid equilibration of dialysate glucose and creatinine than group B. Higher normalized mass transfer area coefficients were evident in group A. In spite of the lower effective glucose gradient in group A, the transcapillary ultrafiltration capacity (TUFC) showed no difference between the two groups. When the slope indices of the regression equations between the two groups were compared, the slopes of the regression in the relationship between TUFC and dialysate (D) ratios D/D₀ glucose or D/P creatinine in group A were steeper than those in group B. Results of the present study indicate that the larger peritoneal area to infusion volume in patients with smaller body size results in both a rapid equilibration of solutes and sufficient transcapillary ultrafiltration.     

Modification of peritoneal ultrafiltration capacity in children undergoing peritoneal dialysis

Eleven children (7 girls and 4 boys) 2 1/2 to 17 years and 8 months of age were treated with CAPD for periods ranging from 6 to 31 months. All children were treated with commercially available dialysate solutions containing lactate. Peritoneal ultrafiltration capacity (PUFC) decreased progressively in all children without accompanying decrease in peritoneal urea and creatinine clearances. Five children developed membrane failure with negative ultrafiltration. One episode of peritonitis occurred in one of these 5 children and in 4 of them only 1.5% glucose solutions had been used. After an initial period (ranging from 14 to 31 months) of CAPD, 2 children were treated with Intermittent Ambulatory Peritoneal Dialysis (IAPD) and two others with Intermittent Cycling Peritoneal Dialysis (ICPD). In these 4 children, PUFC increased within one month from -3.75 ml/kg/day to + 5 ml/kg/day. By providing a shorter dwell time, IAPD and ICPD may allow a reduction in net inward transport of glucose, the maintenance of osmolar gradient and preservation of ultrafiltration capacity. Furthermore, periods of rest may allow some recovery from the progressive deterioration of the peritoneum resulting from long-term irrigation of the peritoneal cavity. These results indicate that IAPD and CPD may be superior to CAPD to maintain the ultrafiltration capacity of the peritoneum.     

持续性腹膜透析儿童腹膜平衡试验及结果分析

目的通过腹膜平衡试验（PET）探讨我国慢性腹膜透析（PD）儿童腹膜转运特性特点。方法对6例持续性非卧床腹膜透析（CAPD）患儿（2—14岁）行10次儿童标准PET,参照Twardowski和儿科腹膜透析联盟（PPDSC）标准评价腹膜溶质转运类型。结果本组患儿首次PET于PD开始后平均（38．74±15．6）d进行。4h肌酐清除率（4h-D／P）和4h葡萄糖吸收率（4h-D／D0）分别为（0．85±0．24）、（0．34±0．19）。依Twardowski和PPDSC腹膜转运类型评价标准,本组腹膜溶质转运类型分别为高转运型6例（6／10）、高平均转运型1例（1／10）、低平均转运型3例（3／10）,无一例低转运型;两种标准分型的总符合率100％。本组腹膜葡萄糖转运类型分别为高转运型3例（3／10）、高平均转运型4例（4／10）、低平均转运型1例（1／10）,低转运型2例（2／10）;两种标准分型的总符合率90％。连续PET显示转运类型变化不一,腹膜炎后4h-D／P升高。结论本组CAPD儿童腹膜溶质和葡萄糖转运类型均以高转运和高平均转运为主（7／10）,呈偏态分布,提示儿童腹透溶质清除充分,但水超滤能力不足;标准儿童PET及其评价标准完全符合Twardowski标准PET要求。腹膜炎后溶质转运能力提高。     

The effect of dialysate volume on ultrafiltration in young patients treated with CAPD

The effect of dialysate volume on ultrafiltration in young patients on continuous ambulatory peritoneal dialysis (CAPD) was studied. Twelve patients were evaluated. Each patient was studied with five different dialysate volumes (30, 40, 50 cc/kg and 2, 3 liters/1.73 m2) and two different dialysate glucose concentrations (1.5% and 4.25%). Dialysate osmolalities were measured at 30 minutes, one hour, two hours, and four hours. Dialysate volume was measured after four hours. Increased dialysate volume was associated with an increase in ultrafiltration rate and a slower fall in dialysate osmolality. It is concluded that since infants have a greater peritoneal surface area per kg than adults, they absorb dialysate glucose at a greater rate when related to body weight. This will lower dialysate osmolality at a faster rate and reduce ultrafiltration. Dialysate volume prescribed for children should not be extrapolated from the adult experience on the basis of 2 liters/70 kg, but rather by surface area (2 liters/1.73 m2).     

Evaluation of 25-hydroxyvitamin D and vitamin D binding protein losses in thirteen children on continuous ambulatory peritoneal dialysis

Thirteen children, 6 females, 7 males, aged 2 to 13 years were studied. At the time of study they were on continuous ambulatory peritoneal dialysis (CAPD) for 1 to 22 months. 25-(OH)D loss in daily dialysate fluids represented 2 to 22 micrograms/day. A significant correlation was found between 25-(OH)D plasma concentration and 25-(OH)D dialysate concentration. 25-(OH)D clearance was correlated to 25-(OH)D binding protein clearance (p less than 0.001). These findings of important 25-(OH)D losses in the dialysate fluid of children on CAPD demonstrate the necessity of carefully adapted vitamin D intakes with such a treatment.     

Pharmacokinetics of recombinant human erythropoietin in children treated with continuous ambulatory peritoneal dialysis

In children treated by continuous ambulatory peritoneal dialysis (CAPD) renal anaemia is preferably treated by intraperitoneal administration of erythropoietin, since subcutaneous administration is painful and frightening for the child. Pharmacokinetics of erythropoietin were studied in three groups of children treated by CAPD. In group subcutaneous (SC) (n=5) erythropoietin was administered subcutaneously, whereas in group intraperitoneal 1 (IP1) (n=8) and intraperitoneal 2 (IP2) (n=8) erythropoietin was given intraperitoneally during a 12-h dwell. Group IP1 received erythropoietin in 20 ml/kg of dialysis fluid, while in group IP2 the hormone was added to only 50 ml of dialysate, irrespective of body weight. The median area under the curve (AUC) was 4064 mU·h/ml (range 2647–24357) in group SC, 1698 (570–5514) in group IP1 and 3577 (1225–6555) in group IP2. In comparison to group SC the AUC was significantly lower in group IP1 (Wilcoxon;P=0.02). The difference between group SC and group IP2 was not statistically significant.In children on CAPD the resorption of erythropoietin after intraperitoneal administration, measured as AUC, is similar to subcutaneous administration, when erythropoietin is administered in 50 ml of dialysate. The dose needed to treat renal anaemia with erythropoietin administered intraperitoneally this way will have to be established in a therapeutic study.     

The importance of continuous ambulatory peritoneal dialysis technics in relation to intermittent peritoneal dialysis in acute renal insufficiency in children. Apropos of 7 cases

We report seven cases of acute renal failure (ARF) treated by continuous ambulatory peritoneal dialysis (CAPD). ARF was caused by hemolytic uremic syndrome in six patients and acute fetal distress in one neonate. Mean age was 28 months (range 6 days-6 years). A flexible Tenckhoff catheter was inserted surgically under brief (10 minutes) general anesthesia in all patients. During the first 24 hours, in order to avoid clogging of the catheter, exchanges were done every 45 minutes with 20 ml/kg dialysate initially, gradually increased to 40-50 ml/kg. Thereafter, 5 to 8 exchanges were done every day (mean duration 9 days, range 4-21) until creatinine clearance reached 15 ml/mn/1.73 m2. No case of peritonitis or leakage was recorded. In two patients, migration of the straight catheter caused flow obstruction. None of the crook-shaped catheters migrated. Because dialysis was continuous and fluid balance could be controlled by using a hypertonic dialysate if called for, optimal protein (1-1.5 g/kg/d) and energy intake were possible. This intake was ensured mainly by continuous enteral nutrition. Improved patient comfort (no immobilization, no repeated punctures) and staff comfort (technical simplicity, independence from a cycler) are further non-negligeable advantages of CAPD.     

THE EXCRETION OF C6–C10-DICARBOXYLIC ACIDS IN THE URINE OF NEWBORN INFANTS DURING STARVATION

ABSTRACT. Gregersen, N. and Ingerslev, J. (Research Laboratory for Metabolic Disorders, University Department of Clinical Chemistry and University Department of Obstetrics and Gynaecology, Aarhus kommunehospital, Aarhus, Denmark). The excretion of C₆–C₁₀-dicarboxylic acids in the urine of newborn infants during starvation. Acta Paediatr Scand, 68: 677, 1979.—The excretion of C₆–C₁₀-dicarboxylic acids, i.e. adipic, suberic and sebacic acids, was measured during the three first days of life in 3 fasting newborns, 2 newborns fed with isocaloric glucose and 2 newborns given mothers'-milk. On the second and third day of life the starved children excreted 27–84 mmol adipic acid/mol creatinine, 6–22 mmol suberic acid/mol creatinine and 4–7 mmol sebacic acid/mol creatinine. The excretion of C₆–C₁₀-dicarboxylic acids in the neonates given glucose or mothers'-milk was, for the first three days of life, 0–9 mmol adipic acid/mol creatinine, 0–10 mmol suberic acid/mol creatinine and 0–4 mmol sebacic acid/mol creatinine. The latter amounts are equivalent to the excretion of dicarboxylic acids in older children. It is argued that the detected dicarboxylic acids are formed by ω-oxidation of long-chain monocarboxylic acids followed by β-oxidation, and that the excreted amounts reflect ω-oxidation activity. It is speculated that the substantial ω-oxidation activity in the starving newborn serve to provide succinyl-CoA-substrate for the citric acid cycle and for gluconeogenesis.     

Clearance of osteocalcin by peritoneal dialysis in children with end-stage renal disease

Osteocalcin is a bone-specific protein whose concentration in blood is a direct reflection of bone turnover. In chronic renal failure, circulating osteocalcin is elevated. This elevation is due to decreased renal clearance and, in some patients, increased bone turnover secondary to renal osteodystrophy. In children receiving continuous ambulatory peritoneal dialysis, mean serum osteocalcin concentrations are substantially lower than in similar patients on hemodyalysis (1). This difference may be due to clearance of the protein by the peritoneal membrane. To test this possibility we examined osteocalcin in 16 infants and adolescents undergoing continuous ambulatory peritoneal dialysis with two commercially available glucose-based dialysis solutions (2.5 and 4.25% Dianeal). Mass transfer of osteocalcin over 5-h dialysis exchange periods was -18.9 +/- 2.8 and -28.4 +/- 7.8 micrograms for the low and high glucose solutions, respectively. Serum levels fell over the course of single exchange periods in concert with increasing dialysate concentrations. There were significant correlations between initial blood concentrations of osteocalcin and the total amount of osteocalcin transferred (r = 0.609 and 0.642 for the high and low glucose solutions, respectively, p less than 0.05). There were also strong correlations between the mass transfers of osteocalcin and those of creatinine (p less than 0.05) and total protein (p less than 0.01) with the 4.25% glucose exchange. The relationships were weaker with the 2.5% glucose exchange. Fractionation of serum revealed a single immunoreactive peak eluting coincident with intact osteocalcin, but two or three immunoreactive peaks were identified in matching dialysate samples, suggesting that both intact osteocalcin and circulating fragments are transferred by the peritoneal membrane.(ABSTRACT TRUNCATED AT 250 WORDS)     

The utility of peritoneal drains in children with uncomplicated perforated appendicitis

Peritoneal drainage in children with uncomplicated perforated appendicitis (UPA) is still controversial. Many pediatric surgeons prefer not to drain the peritoneal cavity in such cases. However, there is no randomized controlled study performed in children. We aimed to study the effects of peritoneal drainage in children with UPA in a randomized prospective trial. One hundred and forty consecutive patients with UPA were divided randomly into 2 groups. Group I (70 patients) consisted of cases with peritoneal drainage, and group II (70 patients) without drainage. UPA is defined as perforated appendicitis with no more discoloration of peritoneal fluid after peritoneal wash out. Cases with localized abscess in the peritoneum were excluded from the study. In all patients, the ages, duration of symptoms, nasogastric drainage and hospitalization, and complications after surgery were recorded. The duration of hospitalization and nasogastric draining time were significantly lower in patients without peritoneal drainage. There was no difference in postoperative complications between the two groups. The onset of oral intake after surgery was significantly earlier in group II patients. Placing drains in the peritoneum does not improve outcome in UPA. Therefore, we do not recommend routine drainage of children with UPA.     

Recent developments in dialysis and transplantation

In the last two decades major progress has been made in the treatment of children with end stage renal disease (ESRD). Dialysis and transplantation have become available for even the smallest infants with improved long-term outcome. Continuous ambulatory peritoneal dialysis (CAPD) and continuous cycling peritoneal dialysis (CCPD) are the major dialytic modalities chosen by the patients and families. The indications to initiate dialysis in infants should probably include, in addition to uremic clinical manifestations, failure to grow, reduced increments in head circumference and developmental delay. CAPD/CCPD provide adequate long term biochemical control of uremia, acceptable control of blood pressure and reduced transfusion requirements. Complications of CAPD/ CCPD are mainly peritonitis, hernias and leaks which are manageable. Despite the benefits of CAPD/ CCPD, renal transplantation is considered the ultimate treatment for children with ESRD, providing them with excellent quality of life and rehabilitation. The outcome of renal transplantation in children is comparable to that of adults except for infants under 2 years of age where results are less optimal. In order to prevent immunologic rejection, which is the major impediment to successful renal transplantation, the best donor recipient histocompatibility matching is attempted, pretransplant blood transfusions are given and immunosuppressive drugs are used. The potential for recurrence of the original disease in the transplanted kidney is not a contraindication to transplantation since it rarely causes graft loss. Rehabilitation with successful renal transplantation is excellent, promising a better life for children with ESRD.     

Pulmonary function in children with chronic renal failure

Lung volumes were measured in 45 children with chronic renal failure and compared to 10 healthy controls. Six patients were receiving conservative treatment (CT), 11 were undergoing regular haemodialysis (HD), 8 were on continuous ambulatory peritoneal dialysis (CAPD) and 20 were post transplantation (TP). We measured vital capacity (VC) and forced expiratory volume in 1 s (FEV-1) with a bell spirometer. In addition residual volume (RV) was determined in CAPD patients. VC and FEV-1 values below the lower limit of predicted normal values from healthy children with the same body height were found in 38% and 52% of all patients respectively (P<0.05). Median values of VC and FEV-1 were lowest in CT and highest in TP patients. Median FEV-1 was significantly reduced to 79% of predicted values in CT and to 82% in HD patients (P<0.05). No correlation was found between FEV-1 and haemoglobin levels or the concomitant use of beta-blocking agents. During a HD session mean FEV-1 increased significantly. In CAPD patients the routine filling of the abdomen was followed by an 11% decrease of RV (non significant) while the other parameters remained stable. It is concluded that lung volumes are frequently reduced in chronic renal failure but remain essentially stable during the dialysis procedures.     

Effect of amino acid containing dialysis solutions on plasma amino acid profiles in children with chronic renal failure

Our previous studies demonstrated that, over single peritoneal dialysis cycles, amino acid-based dialysis solutions (AAD) were effective in dialyzing children with chronic renal failure (CRF) and offered metabolic advantages over traditional glucose dialysis solutions. The AAD, however, resulted in undesirable elevations of certain plasma amino acids, notably methionine. To further investigate the relationship between dialysate and plasma amino acid levels, we assessed the plasma amino acid response to a new AAD with relatively low methionine content (Vamin-based) over separate 5-h cycles with 1.3 and 2.3% AAD in eight patients with CRF (age 1-9 years) on continuous ambulatory peritoneal dialysis (CAPD). There was a net absorption of 70-73% of the amino acids, the net absorption of individual amino acids corresponding with the AAD composition. Plasma amino acid levels rose with AAD, peaking by 1 h postinfusion. Although most amino acids fell to preinfusion levels at the end of the cycle (including methionine), isoleucine with the 1.3% AAD and isoleucine, leucine, phenylalanine, and tyrosine with the 2.3% AAD remained significantly elevated. Having demonstrated in children that amino acids are absorbed from the peritoneal cavity in proportion to the AAD profile, modification of the current AAD is suggested.     

Vitamin D-dependent rickets type II: extreme end organ resistance to 1,25-dihydroxy vitamin D3 in a patient without alopecia

Vitamin D-dependent rickets type II (VDDR II) is a rare syndrome resulting in severe rickets and is resistant to treatment with vitamin D and its derivatives. Patient with this disease, who are frequently the children of consanguinous marriages, present with elevated circulating concentrations of 1,25-dihydroxy vitamin D, the active metabolite of vitamin D, and in vitro studies have indicated a failure of intracellular binding of the hormone. Alopecia has been noted in many of these patients and it has been suggested that this feature may indicate a more marked resistance to treatment. However we describe a 3-year-old boy with this disease who, although having normal hair growth, displayed extreme resistance to treatment with active vitamin D metabolites. In vitro studies of skin fibroblasts disclosed not only an absence of hormone binding or 1,25(OH)₂D₃-induced 24-hydroxylase activity but reduced metabolism of 1,25(OH)₂D₃ itself. In this child, treatment with exogenous 1,25-dihydroxy vitamin D₃ at doses of up to 24g/day, which increased the circulating concentration of the metabolite to greater than 100 times the normal adult mean, failed to alleviate his condition and he died at the age of 39 months. This would therefore suggest that absence of alopecia, in this condition, cannot be regarded as a constant predictive sign of a lesser resistance and of responsivenes to Vitamin D treatment.Abbreviations VDDRII vitamin D-dependent rickets type II - AIK Phos alkaline phosphatase     

Rickets with alopecia-remission following a course of 1-α-hydroxy vitamin D3 therapy

A child is described with rickets and alopecia who did not respond to high doses of vitamin D₃ but who responded to a small dose of 1--hydroxyvitamin D₃. Treatment was continued for 2 years and then stopped. She has not shown any signs of relapse 1 year after stopping treatment. Her alopecia, however, has remained unchanged. One year after stopping treatment, her serum 25-hydroxycholecalciferol and parathormone levels were within normal limits but serum 1,25-dihydroxycholecalciferol was elevated.Abbreviations 25 OH D₃ 25-hydroxycholecalciferol - 1,25 (OH)₂ D₃ 1,25-dihydroxycholecalciferol - 1--OH D₃ 1--hydroxy vitamin D - VDDR II vitamin D dependent rickets type II     

Five years' experience with continuous ambulatory or continuous cycling peritoneal dialysis in children

In 93 children, end-stage renal disease was treated with the new dialytic methods of continuous ambulatory peritoneal dialysis (CAPD) or continuous cycling peritoneal dialysis (CCPD) over 5 years. Modality survival rates at 36 months with CAPD, CCPD, or both were 20%, 93%, and 87%, respectively. Use of CCPD as the primary dilaytic method increased during the study period. The peritonitis rate was one episode per 11.8 patient treatment months and was similar with both CAPD and CCPD. Gram-positive organisms were cultured in 34% of these episodes of peritonitis. Staphylococcus aureus peritonitis was associated with a recurrence rate of 40% and led to catheter replacement in 45% of the episodes. Peritoneal membrane failure necessitating switching to hemodialysis was related to peritonitis in three patients. Of the 74 peritoneal catheters that required replacement, 70% were infected. Serial serum levels of urea nitrogen, potassium, calcium, phosphorus, albumin, and alkaline phosphatase remained stable, whereas serum creatinine level rose slightly over time. Episodes of hyperkalemia, hypercalcemia, and hyperphosphatemia were observed at a frequency of one episode per 12.2, 4.6, and 2.5 treatment months, respectively. Blood transfusions were required in once per 1.5 and 3.3 treatment months in seven anephric patients and in 35 patients with their own kidneys, respectively (P = 0.05). In prepubertal patients who received CAPD or CCPD for greater than 1 year, little or no improvement in growth occurred in relationship to either chronologic or bone age.     

Anatomy and physiology of the peritoneum

The peritoneum is commonly encountered in abdominal surgery. The development and rotation of the primitive gut tube lead to the normal adult arrangement of the peritoneal cavity, which forms bloodless planes allowing the retroperitoneal portions of the bowel to be safely mobilised. The arrangement of the peritoneum also forms spaces in which infected fluid or pus can collect. The microcirculation of peritoneal fluid is now well understood, and the large absorptive surface of the peritoneum can be exploited in peritoneal dialysis. The absorption of gas by the peritoneum following abdominal surgery is faster in neonates than in older children, and understanding this process contributes to the interpretation of post-operative radiographs.     

Renal Osteodystrophy in Patients on Continuous Ambulatory Peritoneal Dialysis

Twelve patients on continuous ambulatory peritoneal dialysis (CAPD) were studied in order to evaluate the progression of renal osteodystrophy (ROD). All patients received doses of 0.01 - 0.02 μg/kg of 1 alpha vitamin D₃(1α - D₃) and 0.1 - 0.15 g/kg of calcium carbonate for 12 - 18 months. Serum total protein, total calcium (Ca), creatinine, inorganic phosphate alkaline phosphatase (ALP), and n-terminal parathyroid hormone were measured regularly. The radiological bone appearance for ROD or rickets and the height standard deviation score were compared between the outset and the end of this study. An increase of Ca values and a decrease of ALP values correlated with a suppression of hyperparathyroidism, and the hyperphosphatemia was controlled in the majority of our patients throughout this study. Two patients had ROD and rickets at the outset of this study, and all patients but one had neither ROD nor rickets at the end of this study. Growth retardation improved or remained stable in 10 patients. Our results indicate that adequate doses of 1α - D₃ and calcium carbonate are effective in the prevention of ROD and rickets in patients on CAPD.     

Hemodynamic effects of peritoneal dialysis in three children following open heart surgery

Summary We studied the hemodynamic responses of peritoneal dialysis (PD) in three children following open heart surgery. Hemodynamic measurements were made prior to a dialysis run, following the instillation of dialysis solution (20 ml/kg), and immediately prior to and 5 min after drainage of the peritoneal cavity. The same protocol was repeated 48 h later. There was a significant increase in right atrial pressure (RAP) and mean pulmonary artery pressure upon instillation of the dialysate into the peritoneal cavity (p<0.01). However, cardiac index, mean arterial blood pressure (MAP), systemic (SVRI) and pulmonary vascular resistances (PVRI), left atrial pressure (LAP), and oxygen saturation did not change significantly. There were no significant differences between responses in the initial study and that performed 48 h later. PD is associated with modest right-sided hemodynamic changes which, in this small group of patients, did not compromise patient care.     

Peritonitis rates and common microorganisms in continuous ambulatory peritoneal dialysis and automated peritoneal dialysis

Background:  The aim of the present study was to perform a multicenter investigation in Turkish children on chronic peritoneal dialysis by examining the rates of peritonitis as well as causative organisms according to year.
Methods:  Twelve pediatric renal units participated in this study and data were obtained by review of the medical records.
Results:  One hundred and thirty-two patients were on continuous ambulatory peritoneal dialysis (CAPD), 21 were on automated peritoneal dialysis (APD) and 59 were on CAPD and APD at different times. Mean durations of CAPD and APD were 24.2 ± 21.1 months and 22.9 ± 12.8 months, respectively. Seventy-one (33%) out of 212 patients had no peritonitis episode. Overall peritonitis rate was one episode per 15.5 patient-months. The peritonitis rate was one episode per 15.4 patient-months for APD and one episode per 15.6 patient-months for CAPD. Coagulase-negative staphylococcus was the most common cause of peritonitis among patients with positive culture (20.6%). While the incidence of Gram-negative infection remained unchanged according to year in patients on CAPD ( P  = 0.68), the rate of Gram-negative peritonitis in children on APD was significantly higher ( P  = 0.03).
Conclusions:  Peritonitis rate was similar in CAPD and APD, but the risk of Gram-negative peritonitis in APD was higher than that of CAPD.