Background/Aims: The continuous growth of the dialysis pool in our unit induced us to organize a third long nocturnal dialysis (LND) session, considering the excellent survival and rehabilitation results reported with this method. This paper analyzes the results and assesses the role of LND among the different dialytic treatment options. Methods: Out of 18 patients on LND, 13 (12 males and 1 female, mean age 52 ± 13 years, time on dialysis 21.8 ± 23.8 months) with >6 months’ experience were studied, and 9 underwent a further metabolic evaluation. LND was performed using 1- to 1.4-m2 Hemophan membranes, bicarbonate buffer, 200–250 ml/min blood flow, and 300–500 ml/min dialysate flow, 8 h three times a week. Kt/V and protein catabolic rate (3-point classic urea kinetics), postdialytic weight, serum albumin, total protein, hemoglobin, Ca2+, phosphate, intact parathyroid hormone, bioimpedance body water, blood pressure, and drug use (antihypertensives, phosphate binders, erythropoietin, vitamin D, hypnotics) were evaluated in each patient during hemodialysis and LND. In the metabolic study (done twice), sodium (compared with the Kimura model), potassium, phosphate, and urea were analyzed in blood and inlet and outlet dialysate after 0, 2, 4, 6, and 8 h. Results: The mortality was low (1 death every 247 patient-months). After 19 ± 8.1 months of LND, the postdialytic weight rose from 68.5 ± 9.6 to 70.8 ± 10.7 kg (p ≤ 0.01), and the hemoglobin concentration rose from 10.8 ± 2.2 to 11.8 ± 1.8 g/dl (p ≤ 0.05); phosphate dropped from 5.6 ± 2.0 to 4.4 ± 1.3 mg/ dl (p ≤ 0.01) and the systolic blood pressure from 152 ± 15 to 143 ± 19 mm Hg (p ≤ 0.05). In the metabolic study, the sodium profile was significantly lower during the last 4 h than in the Kimura model. The potassium concentration, stable between 4 and 6 h, rose against the gradient during the last 2-hour period. The behavior of sodium and potassium during the last part of the dialysis session can be taken to indicate exhaustion of the sodium/potassium pump. Phosphate showed a gradual reduction with no intradialytic and only a moderate postdialytic rebound. The postdialytic urea rebound was 23.4%. Conclusions: LND is a useful additional tool for nephrologists in treating chronic renal failure, it is easy to organize, and it shows overall good results. Together with other dialysis methods, this schedule permits individualized treatment for each uremic patient.

BACKGROUND:The need of collecting data concerning uremic local population requested by EDTA registry and, more recently, by the Italian dialysis and transplant registry (RIDT) has led different Italian regions to organize structures able to give such clinical and epidemiological informations.METHODS:In Aosta Valley (where live nearly 120.000 people) a data collection has been activated since 1981 on paper support and since 1995 (with data from December 1994) on computer registry. If compared to more experienced Italian structures, such as Piedmont and Lombardy regional registries, RDTVA has the advantage of receiving data from a unique Dialysis centre (composed by a hospital area and a limited care centre).RESULTS:During these years, according to what happened in the rest of Italy, in Aosta Valley the uremic population increased with a per million population (pmp) rate prevalence from 125 patients in 1981 to almost 1000 in 1998. Also the incidence showed a similar trend, with 110 patients/pmp in 1981-82 and 160 in 1997. The gross mortality rate concerning years 1995-98 was about 12%, the main death causes being cardiovascular events (60%), similarly to national data.CONCLUSIONS:Even with the limits deriving from small numbers, RDTVA, because of its favourable position, can play the role of epidemiological observatory for uremic diseases and contribute to future health policy.

A 59-years-old male patient was admitted to our Service because of acute renal failure with maintained diuresis (creatinine at admittance 6.2 mg/dl), preceded by malaise and weight loss. Clinical examination was normal and no investigation lead to a sure differential diagnosis of acute renal failure. The only abnormal laboratory investigations were: marked hypercalcaemia (12.7 mg/dl), slightly depressed parathormone (10 pg/ml) and anemia (Hb 11.2 g/dl). Also instrumental investigations performed were inexpressive. The abrupt appearance of an unilateral 7th cranial nerve paralysis lead to start a steroid therapy followed, in some days, by the normalization of calcium level and by a partial improvement of renal function. A renal biopsy was finally performed which permitted the diagnosis of interstitial granulomatous nephritis according to a sarcoidosis disease. Steroid therapy was continued allowing to a progressive, although not complete, recovery of renal function. The case peculiarity consists of isolated renal lesions with a severe expression of renal disease. The absence of classical disease criteria (pulmonary involvement firstly), in our case total body Gallium-67 scintigraphy was normal, should not exclude the diagnosis of sarcoidosis. The authors underline the importance of renal biopsy in detecting interstitial renal lesions potentially leading to uremia.

Whether to use peritoneal dialysis (PD) or hemodialysis (HD) is a major decision in terms of clinical outcome and management implications; the final choice is difficult because of the conflicting results of comparisons reported in the literature. A review of studies comparing survival shows either superiority of HD, or superiority of PD, or equivalence of the two techniques, but an analysis of the comparisons as a whole brings to light two clear phases in the survival curves. In the first, residual renal function (RRF) gives PD an advantage, or at least puts it on the same level as HD. In the second phase, the reduction in Kt/V as RRF declines gives PD a potential risk. After a few years of PD treatment a sharp watch is therefore necessary to detect signs of under-dialysis promptly and to shift the patient to HD, In patients without RRF it is more difficult to control hypertension with PD and they are more prone to hyperhydration. Despite a widespread belief in the Eighties that PD was the treatment modality of election for diabetics, HD is in fact preferable in these patients, except younger ones. High-turnover and low-turnover bone lesions are more frequent respectively in HD and PD patients. Anemia is better controlled with PD, Blood lipids and nutritional indices are less well controlled with PD. Despite poor technical survival, the "pool" of patients treated with PD frequently reaches 20-30% because it is indicated as first treatment in a large proportion. PD preserves renal function better than HD and is useful while awaiting renal transplantation, with faster postoperative restoration of diuresis. The quality of life with PD as home treatment is usually better than with HD, In conclusion, dialytic centers should establish an integrated PD/HD programme as the two methods are not competitive but are different tools for the treatment and rehabilitation of uremic patients.

Recently developed devices provide detection of access recirculation (AR) and cardiopulmonary recirculation (CPR) by optical, thermal, conducimetrical, and ultrasound methods (USM). We evaluated the last one both in vitro reproducing AR by a bypass pump and in vivo. In vitro, the USM sensitivity was about 5%. In vivo, the USM was compared with the traditional urea method (UM) in 69 patients. 8.7% of the cases resulted positive by both UM and USM. One case was USM positive and UM negative. The UM sensitivity threshold was 6-10%. The accuracy (in vitro) and the repeatability (in vivo) of the USM were satisfactory. USM clearly distinguished AR from CPR. In conclusion, AR determination by USM, avoiding misleading interferences with CPR, is a rapid, easy, and noninvasive method to routinely exclude a potential cause of reduced dialytic efficiency.

(Table 1). The AR reversal lasts a few seconds afterthe interruption of the cycling of some venous bloodAlthough the non-single-pool behaviour of urea kinet- flow to the dialyser. Its recognition is one of the mostics has been pointed out [1–5], and shown to be important goals of urea kinetics, in order to detect therelevant particularly in high-eYciency dialysis [6], the cause of a decrease in eYciency of dialysis or to predictneed to take urea disequilibrium into account even forpractical purposes has become evident in recent years,

The vascular access in emergency represents a basic need for every nephrologist in order to realize an extracorporeal circuit necessary to perform hemodialysis and many other derived therapies. In the eighties a progressive abandonment of the external shunt was noted with a concomitant increase of vena cava catheterization simpler to perform, especially under echographic control, and made increasingly possible by continuous technological improvements. The femoral access is utilized in about 30% of cases, especially in critically ill patients, due to easy performing procedures and few complications. Subclavian vein is abandoned as a first choice in favour of the jugular vein due to frequent and severe early complications and to thrombo-stenotic lesions observed in about 50% of catheterizations. Prevention and rapid treatment of the complications and careful management have an important role in obtaining a prolonged catheter survival. Even if, when possible, the classical arterio-venous fistula remains the ideal solution, at least in particular patient categories a jugular vein utilization as permanent access is justified.

Classical urea kinetic model (UKM) has been followed by several proposals to determine dialysis adequacy either by direct quantification (DDQ), either by simplified two-points formulas (pre- and post-dialysis BUN), or by mUKM, a modified three-point algorithm (pre-post and pre-next dialysis), where urea distribution volume is input to obtain clearance and urea generation rate. Our new formulas (mUKM2) are derived from urea mass balance, and avoid iterative calculation: their results are similar to those obtained by UKM and mUKM when the standard post-dialysis BUN value is employed. On the contrary, when the equilibrated net-rebound value (Cpwnr) is employed their results are very close to the reference DDQ model: however the new approach is simpler and more practical, to measure dialysis dose taking account of the urea rebound phenomenon.

The outputs of a new on-line dialysate urea monitor (UM) were compared to a urea kinetic model (UKM) and to dialysis direct quantification (DDO) in 13 patients. As for urea extraction and predialysis urea level, a good degree of correspondence was found between UM and laboratory data. Kt/V UM (1.21) is intermediate between Kt/V UKM (1.28) and Kt/V uKM using the post-rebound urea value (1.14) or Kt/V DDQ (1.14). Passing and Bablok regression analysis indicated no systematic error between Kt/V UM and Kt/V DDQ . The percentage differences in nPCR by UM, UKM and DDQ were not significant, but the standard deviations were wide. The UM approach is very simple and practical, avoiding blood sampling, laboratory analysis and data handling. It is reliable enough for clinical practice. Compared with traditional urea kinetics, Kt/V computation by a mathematical elaboration of the dialysate urea profile drawn from several points theoretically invites fewer errors due to the analytical procedure.

To verify the accuracy of a urea monitor (UM) to assess dialysis adequacy, it was compared with a modified direct dialysis quantification method (mDDQ) and with a Casino modified urea kinetic model (mUKM) algorithm. Simplified Jindal and Daugirdas formulas, an anthropometric body water Watson formula, bioelectric impedance analysis, and the Garred model have also been considered. Concerning urea removal, UM results are close to mDDQ, as are the predialytic blood urea nitrogen values obtained by UM in the initial equilibration test. Urea distribution volume results for UM, mDDQ, and bioelectric impedance analysis are similar, whereas it appears clearly overestimated by the Watson formula. Urea monitor clearances are not significantly different from mDDQ, unlike UM Kt/V, which is slightly higher than mDDQ reference value, although with a satisfactory degree of concordance. Rebound effect must be considered by sampling after the equilibration time (et) when mUKM or simplified Kt/V formulas are used: mUKMet Kt/V results are quite similar to mDDQ, as is the Daugirdas value. Regarding NPCR, UM results are neither significantly different from mDDQ nor from the Garred model, whereas mUKM results are significantly overestimated. When rebound is considered, NPCR by mUKMet and NCPR by mDDQ are identical. The UM approach is simple and practical, with a satisfactory degree of reliability for clinical practice.