[Clinical evaluation of the Paired Filtration Dialysis in children]. / Valutazione clinica della Paired Filtration Dialysis nel bambino.

PURPOSE: An important challenge for a pediatric nephrologist is to achieve in children the innovations of current adult dialytic technology. METHODS: Five children, mean age 14.1 +/- 1.5 yrs, mean weight 31.5 +/- 5.8 kg, mean dialytic age 32 +/- 20 months, were evaluated after a 6-month treatment with paired filtration dialysis (PFD). We used two capillary membranes: a 0.4 m 2 polysulfone hemofilter and a 0.8 m 2 cuprophan dialyzer. There was a reinfusion system (1540 +/- 150 mL/h) between these two filters. QD 500 mL/min and QB 230 +/- 10 mL/min. Ultrafiltration (UF) 2400 mL/h was planned for the hemofilter. At base-line and after 6 months of treatment, in addition, we evaluated routine clinical parameters, and other parameters such as beta2-microglobulin, dialytic adequacy (Kt/V) and nutritional status (dietetic diary). The data were analyzed using the Student's t-test for paired values. RESULTS: Medium values of small molecules did not demonstrate meaningful variations after 6 months of treatment. The extraction percentage after each session was between 63% phosphorous and 76% for urea, but only 25% for convection. Instantaneous urea clearance after 60 min was 178 +/- 10 mL/min. Dialytic efficiency and nutritional intake were appropriated: Kt/V 1.66 +/- 0.2; PCRn 1.65 +/- 0.2; protein intake 2.2 +/- 0.5 g/kg/die; caloric balance 71.2 +/- 15 Kcal/kg/die; protein balance 0.53 +/- 0.4 g/kg/die; and azotic balance 85.8 +/- 74 mg/kg/die. We confirmed the good depuration capacity from the middle molecules with convective treatments: beta2-microglobulin extraction was 53%. Moreover, in children we found good clinical tolerance to PFD with modest interdialytic symptomatology: headache (8%), hypotension (6%), and cramps and vomiting (<2%). Increased priming of the extracorporeal circuit was not a significant technical problem. The cuprophan membrane has been subsequently replaced with the polysulfone membrane. CONCLUSIONS: We can assert that this technique can also be performed in the pediatric age with similar results as in the adult age: good depuration of the small and averages molecules, good clinical tolerance, and shortening the dialytic sessions.

Apheresis in primary focal segmental glomerulosclerosis of native and transplanted kidneys: a therapeutic protocol.

BACKGROUND: Patients with focal segmental glomerulosclerosis (FSGS) develop nephrotic syndrome and terminal renal failure in most cases. FSGS reappears in 15-50% of transplanted kidneys and frequently causes the graft loss. Sera from patients with FSGS of native or transplanted kidneys contain some proteinuric or permeability factors (PF) which can be removed by means of plasma exchange (PE) or protein A Immunoadsorption (IA). METHODS: We suggest a therapeutic protocol, for patients with biopsy proven FSGS of native or transplanted kidneys, resistant to steroid and immunosuppressive therapy, based on the association of PE or IA to conventional drug therapy. Daily proteinuria, renal function, serum albumin and circulating level of proteinuric factors (permeability test) will be monitored at regular time intervals during the apheresis cycle, which will be intensive at the beginning (8-10 sessions in 4 weeks) and very gradually discontinued. Results. We will consider satisfactory remission the reduction of proteinuria below 1 g/day, improvement of renal function, normalization of serum albumin level (> 3.5 g/dl). Partial remission will be considered: proteinuria below 3 g/day, stable renal function, serum albumin level between 3 and 3.5 g/dl. Permeability test, if positive at baseline examination, should be negative after apheresis. CONCLUSIONS: The primary endpoint of our protocol is: lasting remission (satisfactory or partial) after the apheresis suspension. Secondary endpoints are: maintained remission with continuing apheresis sessions, correlation between permeability activity and disease activity, identification of responders and non responders patients on the basis of positive permeability test.

Normal values of the bioelectrical impedance vector in childhood and puberty.

The purpose of this study was to determine the reference, bivariate, and tolerance intervals of the whole-body impedance vector in Italian children. This was a cross-sectional, multicenter study, and participants were chosen from the general school population. The impedance vector (standard, tetrapolar analysis at 50-kHz frequency) was measured in 3110 subjects, ages 2 to 15 y, and 2044 healthy children (1014 male and 1030 female) with weight and height within the 95th percentile were selected for the analysis (resistance-reactance graph method). The age-specific 95% confidence intervals of mean vectors and the 95%, 75%, and 50% tolerance intervals for individual vector measurements were plotted using resistance and reactance components standardized by the subject's height. Mean vectors from both sexes with separate 95% confidence ellipses were considered as representative of eight different age groups, from 2 to 13 y. There was a statistically significant sex effect on vector distribution from boys and girls in the age group of 14 to 15 y. The impedance vector distribution of children was also compared with healthy adult subjects (354 male and 372 female, age 15 to 85 y). There was a progressive, statistically significant vector shortening from age 2 to 15 y toward the adults' vector position. In conclusion, we established the trajectory followed by the mean impedance vector in children over ages 2 to 15 y and also obtained the reference, bivariate, and 95%, 75%, and 50% tolerance intervals of the impedance vector by age for healthy children, with which the vectors from children with altered body composition can be tested.

Therapeutic apheresis in children: experience in a pediatric dialysis center.

The use of apheretic procedures in pediatric patients has always been restricted by technical difficulties and the low incidence of diseases requiring this kind of treatment. The aim of the present study was to describe the solutions adopted to solve technical difficulties related to priming, vascular access and monitoring and then to evaluate clinical results. Between 1982 and 2000, 51 consecutive children (28 male, 23 female) with a mean age of 4.9 +/- 4.8 years (3 months-14.8 years) and a mean weight of 19.7 +/- 12.8 kg (5-52 kg), with renal and/or extra-renal diseases requiring apheretic procedures were selected for the study. The overall number of procedures performed were: 226 plasma-exchange (PE), 6 LDL-apheresis (LDL-A) and 8 protein A immunoadsorption (IAPA) sessions. Our therapeutic protocol involves hematic flux of 20-100 ml/min and ultrafiltration of 5-20 ml/min. In each 70-95 minute session we exchanged plasmatic volume with fresh frozen plasma or with a solution of 6% albumin in lactated Ringer's, using heparin (10-20 UI/kg/h). We used Paired Filtration Dialysis Monitor in PE and LDL-A; Citem 10 in IAPA. As plasma separator, we used a filter made of polypropylene, 0.2 m2 surface, 30 ml priming (Hemaplex BT 900). Hemolytic uremic syndrome was the most commonly treated disease (18/51 cases) with good results in 10/18 cases. We recorded, good results in vasculitis as well, in one girl with focal glomerulosclerosis in transplanted kidney and rapid improvement in all children with Guillaine-Barré Syndrome. PE treatment was effective in metabolic disorders such as tirosynemia and familiar hypercholesterolemia. Only 4/12 patients with acute liver failure due to viral hepatitis recovered. We had poor results in the remaining eight cases. Complications were rare and no viral infection was found in any patient. Our data show that it is possible to use these procedures in pediatric patients even though clinical indications and real effectiveness still need to be cleared up.

[Echographic diagnosis of nephro-urological neoplasia in a pediatric nephrology center]. / Diagnosi ecografica di neoplasie nefro-urologiche in un centro di nefrologia pediatrica.

The use of ultrasound for the diagnosis of urologic neoplasms in simple and accurate. Nowadays nephrologists and urologists advocate the use of ultrasound and the procedure now plays a complementary role of the clinical examination. We present a retrospective study regarding our experience with ultrasonography in the diagnosis of urologic problems. In the period february 95-february 96 we performed 672 ultrasound examination on children ranging in age from 30 days to 16 years. All examinations were performed using a 3.5-5 MHz real time convex scanner. The patients were examined in the supine position for imaging of the bladder and in the prone position for imaging of the kidneys. We report 3 cases of neoplasm of the genito-urinary tract screened with the use of ultrasounds in a selected paediatric population.

[Plasma profile of free amino acids in children with chronic renal insufficiency undergoing hemodialysis therapy]. / Studio del profilo plasmatico degli aminoacidi liberi in bambini con insufficienza renale cronica in terapia emodialitica.

Some Authors found changes in plasma aminoacids concentration in patients with chronic renal failure treated with conservative therapy or with dialysis. Particularly they observed a reduction in the concentration of essential aminoacids (EAA) and an increase of the non essential (NEAA), with increase in their ratio. In our study we analyzed the plasma aminoacids pools in 12 children with chronic renal failure treated with hemodialysis. We have measured the plasma aminoacids concentrations before and after hemodialysis to evaluate their variations and their role in the pathogenesis of some symptoms of uremia. A decreased concentration of EAA and an increased concentration of NEAA, before hemodialysis, were observed. These findings were not modified by this therapy, but turned out to be related to protein intake.