Chronic peritoneal dialysis in paediatrics: Experience of a national registry

The results of the first 3 year' 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%.     

Incremental peritoneal dialysis: effects on the choice of dialysis modality, residual renal function and adequacy

There is still disagreement on whether peritoneal dialysis (PD) should begin with a full dose (Full_Dial) or with incremental doses (Incr_Dial) to compensate for the amount of Kt/V no longer supplied by the residual renal function (RRF). The aim of this study is to assess the effects of an Incr_Dial protocol on the choice of dialysis modality, RRF, and adequacy. The Incr_Dial protocol in our center is as follows: for patients with a glomerular filtration rate (GFR)>5 ml min(-1), PD is initiated with two exchanges per day (continuous ambulatory PD (CAPD)) or four sessions per week (ambulatory PD (APD)); and hemodialysis (HD) is initiated with two sessions per week. The PD dose is then increased in proportion to the reduction in the GFR as follows: GFR< or =5 and >3 ml min(-1)=3 CAPD exchanges or five APD sessions; GFR <3 ml min(-1)=full dialysis dose (Full_Dial). The effects of the Incr_Dial protocol on the choice of dialysis modality were assessed on 87 patients (pts) (age: 69.3+/-13.1 years) who initiated dialysis between 1 January 2004 and 31 May 2007. The effects of Incr_Dial on RRF and dialytic adequacy were assessed in 11 pts treated with two CAPD exchanges per day for a total of 106 months (mean+/-s.d. 9.7+/-6.5), and then treated with three CAPD exchanges per day for an additional 105 months (9.4+/-8.3). The use of Incr_Dial determined the choice of PD in 27 of 44 pts (61.4%) without indications or contraindications to HD or PD. CAPD was chosen by 20 of these pts (74.1%), whereas APD was preferred by 6 of the 8 pts switched from Incr_Dial to Full_Dial. During Incr_Dial, a significant reduction in the loss of GFR of 2.4+/-3.1 ml min(-1) year(-1) was observed when compared to the pre-dialysis period. Incr_Dial allowed for adequate clearance, as confirmed by the Kt/V (2.07+/-0.2), protein nitrogen appearance (1.17+/-0.13), and biochemical parameters. Ultrafiltration (UF) with icodextrin (772+/-166 ml per exchange) provided a daily UF of 517+/-296 ml day(-1) and remained unchanged when the duration of the dwell time increased significantly from 12.3+/-1.4 to 17.5+/-2.6 h.     

Analysis of the factors conditioning the diffusion of peritoneal dialysis in Italy.

BACKGROUND: The diffusion of peritoneal dialysis (PD) in Italy is lower than expected on the basis of indications and contraindications reported in literature. METHODS: To analyse the factors influencing the use of PD in Italy, we used data from the first National Census of the Italian Society of Nephrology relating to 9773 incident patients (Incid(HD + PD)) in 2004 and 43 293 prevalent patients dialysed in 658 centres at 31/12/2004 (337 public centres, 286 private centres, 12 paediatric centres, 15 research or religious institutions and 8 unspecified). RESULTS: The percentages on PD of total incident (Inc(PD)%) and prevalent dialysis patients (Prev(PD)%) were 15.9% and 10.3%, respectively with considerable variations from region to region and from centre to centre. The Inc(PD)% was higher in regions with fewer patients on dialysis in private centres. In the private centres, the Inc(PD)% was 0.4%. Of the 325 non-paediatric public centres, 116 (35.7%) do not use PD: compared with the 209 centres which do, these centres have a lower mean Inc(HD + PD) and Prev(HD + PD) per centre (13.0 +/- 12.3 vs 28.6 +/- 18.0 - 51.8 +/- 35.7 vs 117.3 +/- 66.4 patients, P < 0.0001), and more haemodialysis (HD) stations available (3.0 vs 3.5 patients per HD station, P < 0.0001). However, the significant influence of cultural and motivational factors on the use of this method is demonstrated by the fact that it is used by 34% of the smaller non-paediatric public centres, and is not used by 19% of the larger non-pediatric public centres.     

Butyltin Species in Benthic and Pelagic Organisms of the Saguenay Fjord (Canada) and Imposex Occurrence in Common Whelk (Buccinum undatum)

The distribution and accumulation of butyltins in various tissues of 13 benthic and pelagic species living in the sub-Arctic Saguenay Fjord (Canada) were investigated. Butyltin contamination was ubiquitous in this ecosystem with tributyltin (TBT) biota to sediment accumulation factors (BSAF) ranging between 0.22 and 11, but without any important biomagnification between trophic levels. The large range of butyltin compounds accumulating within different tissues of the species collected from all trophic levels was from 7 to 1238 ng Sn g⁻¹ d.w. and indicates an exceptional contamination level only found in northern coastal areas exposed to an intensive traffic of commercial ships. Results show that bioaccumulation in organisms depends on three main factors: (1) the actual contamination level in their habitat, (2) their assimilation pathway by water, sediment or diet, and (3) their ability to metabolize TBT and excrete metabolites. By their lack of an efficient TBT degradation system, bivalves are subject to accumulate more butyltins (from 890 to 993 ng Sn g⁻¹ d.w. for TBT and from n.d to 138 ng Sn g⁻¹ d.w. for metabolites) whereas most burrow-dwelling organisms are able to degrade TBT and their butyltin levels ranged from 86 to 239 ng Sn g⁻¹ d.w. for TBT and from 7 to 106 ng Sn g⁻¹ d.w. for metabolites. Acadian redfish (Sebastes fasciatus) feeding preferentially on shrimps and small crustaceans rich in TBT showed a contamination level about three times higher than eelpout (Licodes vahlii). The latter species living in contact with the sediment and feeding on worms and other burrowing species had a lower proportion of TBT in their tissues. Finally, deleterious effects of butyltins in the Saguenay Fjord were assessed by the significant occurrence of Imposex in common whelk (Bucinum undatum) in two sites from Baie des Ha! Ha!. Results revealed that the effects of Imposex were accentuated close to the source of contamination, at Port-Alfred harbour, since the total of imposexed whelks collected at site A (the mouth of Baie des Ha! Ha!) was 12.5% and reached 52.6% at site B (Port Alfred). Although the incidence or frequency of imposex was low in site A compared to site B, the relative penile length index (RPL) values, a measure of the degree or severity of imposex, was similar at both sites indicating the presence of TBT with higher concentrations in site B.     

Highly persistent butyltins in northern marine sediments: a long-term threat for the Saguenay Fjord (Canada)

An exhaustive study of the distribution of butyltin species was conducted in the sediment of the Saguenay Fjord (Canada), a semi-enclosed marine system with sediment permanently submitted to sub-Arctic cold conditions. Concentrations of total butyltins (tributyltin [TBT], dibutyltin, and monobutyltin) ranged from 6 to 288 ng Sn/g dry weight and were typical of those reported for contaminated coastal areas despite limited seasonal traffic of commercial vessels in the fjord. The distribution profiles of butyltin species in four sediment cores clearly indicated the high persistence of TBT that was dominating other species. The particular oceanographic conditions of the Saguenay Fjord (low seawater temperature, anoxic sediments, and low exchange rate of deep waters) combined with a high sediment/pore-water partition coefficient (Kdobs = 1.0 x 10(4) to 1.2 x 10(4) L/kg) and a low sediment/ water diffusive flux of TBT (J1 = 13 x 10(-8) mol/m2/year) are responsible for the burial and preservation of TBT in this marine ecosystem. The half-life of TBT in deep sediment was estimated to be approximately 87+/-17 years (+/-SEM), which implies a much slower degradation rate than any previously reported. Finally, a flood event that occurred five years before the sampling enabled us to calculate a very slow diffusive flux from the preflood to the postflood layer (J2 = 2 x 10(-8) mol/m2/year), indicating an almost permanent sequestration of TBT in the buried layers.