[Treatment of fluid overload and kidney failure with periotoneal dialysis after heart surgery]. / Trattamento del sovraccarico di circolo e dell'insufficienza renale mediante dialisi peritoneale nel postintervento cardio-chirurgico.

BACKGROUND: Infants undergoing cardiac surgery with prolonged cardio-pulmonary bypass are particularly exposed to the risk of acute renal failure for renal hypoxia due to low cardiac output. METHODS: To limit fluid overload deriving from oligo-anuria and low cardiac output we have recently adopted an early peritoneal dialysis protocol, positioning the peritoneal catheter during the intervention and performing early exchanges at first signs of inadequate diuretic response and/or "leaky capillary syndrome" with diffuse edema. From 1-1 to 31-12-1997 12 patients (8 males), of median age of 65.5 days (range 1-350 days) and median weight of 3463 g (range 2380-6550 g) were treated with peritoneal dialysis (automated exchanges of 10 ml/kg body weight of 1.5% glucose, dwell time 20 minutes). Cardiac pathologies included complex hearth malformations. Cardiopulmonary bypass lasted a mean of 202 minutes (range 102-372 minutes). The children were treated for a minimum of 1 to 42 peritoneal dialysis sessions. The infusional therapy included human albumin and fresh frozen plasma to substitute losses and furosemide at the dose of 4 mg/kg/day to reduce the "leaky capillary syndrome". RESULTS: The results were very satisfactory: only 3 children died in the first 30 days after surgery. Renal function was normal at the end of the observation in 8/12 cases, and 2 cases presented chronic renal failure. CONCLUSIONS: Since similar series report a mortality rate of 33-79%, it is suggested that early peritoneal dialysis may have positively influenced the final survival rate.

Providing the right stuff: feeding children with chronic renal failure.

The progressive loss of renal function in children with chronic renal failure (CRF) has a negative influence on their nutritional status and statural growth. Supportive therapies with 1-25 dihydroxy-vitamin D3, recombinant erythropoietin and growth hormone have significantly improved the biochemical and clinical features but the success of these therapies is largely related to an appropriate diet, with adequate protein/caloric intakes. Children more than adults have minimal protein requirements to avoid malnutrition and growth impairment FAO/WHO and RDA recommendations save as guidelines for a correct diet in children with CRF. Following these allowances leads to a "normoproteic" diet, with a protein intake which is often half the unrestricted one in Western European countries, but which is still likely to be not enough to protect against renal deterioration. Indeed the European Study Group for Nutritional Treatment of CRF in children failed to show a significant effect of diet on the mean decline of glomerular filtration rate over two years.

Acetate intolerance is mediated by enhanced synthesis of nitric oxide by endothelial cells.

The clinical picture of acetate intolerance strictly mimics the nitric oxide (NO) effect, including smooth muscle relaxation and extreme vasodilation. Because acetate induces production of cAMP, which is a powerful stimulus of NO synthase (NOS), we evaluated the effect of different dialysate solutions with and without acetate on NOS activity in endothelial cells (EC). NOS activity of EC, evaluated as H3-citrulline produced from H3-arginine, was modulated by the dialysate composition (e.g., 38 mmol/L acetate produced an increase of 3.2 +/- 0.39-fold compared with basal values (P < 0.0005), and the small amount of acetate (4 mmol/L) in 35 mmol/L bicarbonate solution increased the NOS activity by 2 +/- 0.49-fold (P < 0.05). Conversely, the acetate-free solution produced no effect on NOS activity. The mRNA encoding for inducible NOS was highly expressed in EC incubated with acetate buffer and also with acetate in bicarbonate dialysis buffer. The EC proliferative index was depressed by acetate (P < 0.0005), and tumor necrosis factor synthesis was increased (P < 0.0005) compared with acetate-free buffer. This study suggests that dialytic "acetate intolerance" can be induced by the activation, through cAMP and tumor necrosis factor release, of NOS. The small amount of acetate in bicarbonate dialysate, although capable of inducing in vitro NOS activation, is likely to be rapidly metabolized, whereas the large amounts of this anion in acetate fluids overwhelm metabolism by the liver. Acetate-free dialysate is the only solution that provides an acceptable level of biocompatibility both in vivo and in vitro.

[Is HCV RNA detectable in the ultrafiltrate?]. / L'RNA dell'HCV è riscontrabile nell'ultrafiltrato?

We investigated by molecular biology the possibility that the HC virus passes by the dialysis membranes into the ultrafiltrate, making the HD monitor a way of HCV transmission. HCV-RNA was tested in blood and in UF samples during 2 HD sessions at T-0, 30, 60, 120 min and at HD end. HCV-RNA was measured by RT-PCR. Viraemia in patients was > 10(-4) gen Eq/ml and remained unchanged along HD, HCV-RNA was not found in whole UF and its x100 concentrates during the HD. We failed to prove the passage of the HCV into the UF, at least in standard conditions.

Enhanced production of nitric oxide by blood-dialysis membrane interaction.

Nitric oxide (NO) is a powerful vasoactive product of endothelial origin, and one of its major effects is vasodilation, leading to hypotension. The role of NO in some complications of uremia is still debated. This study evaluated whether endothelial NO synthase activity could be modulated by the exposure of healthy blood to hemodialysis materials. In vitro hemodialysis sessions were performed with cuprophan and polymethylmethacrylate membranes. Blood samples from a healthy donor after recirculation for 0, 5, 15, 30, and 60 min were coincubated for 6 h with a murine endothelial cell line (t.End.1); mRNA for inducible NO synthase and enzyme activity, measured as (3H)citrulline produced from (3H)arginine, were detected. The release of interleukin (IL)-1 beta and tumor necrosis factor-alpha (TNF-alpha) from recirculating lymphomonocytes was measured, too. The NO synthase activity of endothelial cells was stimulated by blood dialyzed with cuprophan, peaking at 15 min (11-fold increase in comparison to the basal values), whereas polymethylmethacrylate was ineffective (P < 0.01 versus Cuprophan). Dialysis with cuprophan, but not with polymethylmethacrylate, induced in endothelial cells the expression of mRNA encoding for inducible NO synthase. The release of IL-1 beta and TNF-alpha after 6 h by recirculating lymphomonocytes paralleled the NO synthase activity profile in endothelial cells and was significantly higher after cuprophan exposure than after polymethylmethacrylate (P < 0.0001). In conclusion, the activity of endothelial NO synthase can be enhanced during the dialysis sessions by the interaction of lymphomonocytes with the membranes, possibly via TNF-alpha and IL-1 beta production.

Chronic peritoneal dialysis in paediatrics: experience of a national registry.

The results of the first 3 years' collaboration of the Italian Registry of Paediatric Chronic Peritoneal Dialysis (CPD) (1986-1988) are presented. This Registry acquired data on the majority of the paediatric patients treated with CPD in Italy, thus providing a national picture in a field where few nationwide surveys are available. Patients of less than 15 years of age at the start of dialysis were enrolled and clinical data collected until the age of 19 years. The number of nephrological paediatric centres participating in the Registry increased from 7 in 1986 to 11 in 1988. The total number of patients on CPD was 70 and the percentage of dialysed children treated with CPD ranged from 40.2% to 43.6%. Data on 89 peritoneal catheters were collected: during 1417 dialysis-months 70 catheter-related complications were observed (1:20.8 dialysis-months); actuarial catheter survival was 92.7% at 6 months, 84.8% at 1 year and 68.8% at 2 years. the incidence of peritonitis changed from 1 episode every 10.9 patient-months in 1986 to 1 every 19.8 in 1988. Abdominal hernias were the other main clinical complication observed. The survival of patients was 92.5% at 3 years, while the technique survival at the same time was 84%.

[Acute renal failure. 3 years' activity of a pediatric dialysis unit]. / Insufficienza renale acuta. Tre anni di attività di un centro dialisi pediatrico.

Acute renal failure is a frequent and dramatic clinical syndrome, producing a wide variety of serious and potentially lethal disorders in infancy. Review of 30 cases of severe acute renal failure occurred from 1985 in our unit reveals that the major causes are: acute tubular necrosis (33%), hemolytic uremic syndrome (16%), post-streptococcal glomerulonephritis (16%). 16 patients aged from 7 days to 15 years weighing 2 to 59 kilos, underwent dialysis: 8 HD, 7 PD, 1 both. Functional recovery occurred in 13 patients (82%); 3 patients died for the condition that precipitated renal insufficiency.