Assessment of weld thickness loss in offshore pipelines using computed radiography and computational modeling.

In order to guarantee the structural integrity of oil plants it is crucial to monitor the amount of weld thickness loss in offshore pipelines. However, in spite of its relevance, this parameter is very difficult to determine, due to both the large diameter of most pipes and the complexity of the multi-variable system involved. In this study, a computational modeling based on Monte Carlo MCNPX code is combined with computed radiography to estimate the weld thickness loss in large-diameter offshore pipelines. Results show that computational modeling is a powerful tool to estimate intensity variations in radiographic images generated by weld thickness variations, and it can be combined with computed radiography to assess weld thickness loss in offshore and subsea pipelines.

Direct effect of the correction of acidosis on plasma parathyroid hormone concentrations, calcium and phosphate in hemodialysis patients: a prospective study.

BACKGROUND: Metabolic acidosis contributes to renal osteodystrophy and together with hyperphosphatemia, hypocalcemia and altered vitamin D metabolism may result in increased levels of intact parathyroid hormone (iPTH) and metastatic calcifications. However, the impact of the correction of metabolic acidosis on iPTH levels and calcium-phosphate metabolism is still controversial. STUDY DESIGN: The effects of the correction of metabolic acidosis on serum concentrations of iPTH, calcium (Ca), phosphate (PO(4)) and alkaline phosphatase were prospectively studied. Twelve uremic patients on maintenance hemodialysis (HD) for 49 months (median; range 6-243 months) with serum bicarbonate levels < or =20 mmol/l were studied before and after 3 months of oral sodium bicarbonate supplementation. Predialysis serum bicarbonate, arterial pH, ionized calcium, plasma sodium, plasma potassium, serum creatinine, hemoglobin, K(t)/V, postdialysis body weight, predialysis systolic and diastolic blood pressure were also evaluated before and after correction. RESULTS: Serum bicarbonate levels and arterial pH increased respectively from 19.3 +/- 0.6 to 24.4 +/- 1.2 mmol/l (p < 0.0001) and 7.34 +/- 0.03 to 7.40 +/- 0.02 (p < 0.001). iPTH levels decreased significantly from 399 +/- 475 to 305 +/- 353 pg/ml (p = 0.026). No changes in total serum Ca, plasma PO(4), serum akaline phosphatase, K(t)/V, serum creatinine, hemoglobin, body weight, predialysis systolic and diastolic blood pressures were observed. iCa decreased significantly. CONCLUSIONS: Our study demonstrates that the correction of metabolic acidosis in chronic HD patients reduces iPTH concentrations in HD patients with secondary hyperparathyroidism possibly by a direct effect on iPTH secretion.

Adequacy of dialysis reduces the doses of recombinant erythropoietin independently from the use of biocompatible membranes in haemodialysis patients.

BACKGROUND: The effect of the adequacy of dialysis on the response to recombinant human erythropoietin (rHuEpo) therapy is still incompletely understood because of many confounding factors such as iron deficiency, biocompatibility of dialysis membranes, and dialysis modality that can interfere. METHODS: We investigated the relationship between Kt/V and the weekly dose of rHuEpo in 68 stable haemodialysis (HD) patients (age 65+/-15 years) treated with bicarbonate HD and unsubstituted cellulose membranes for 6-343 months (median 67 months). Inclusion criteria were HD for at least 6 months, subcutaneous rHuEpo for at least 4 months, transferrin saturation (TSAT) > or = 20%, serum ferritin > or = 100 ng/ml, and haematocrit (Hct) level targeted to 35% for at least 3 months. Exclusion criteria included HBsAg and HIV positivity, need for blood transfusions or evidence of blood loss in the 3 months before the study, and acute or chronic infections. Hct and haemoglobin (Hb) levels were evaluated weekly for 4 weeks; TSAT, serum ferritin, Kt/V, PCRn, serum albumin (sAlb), and weekly dose of rHuEpo were evaluated at the end of observation. No change in dialysis or therapy prescription was made during the study. RESULTS: The results for the whole group of patients were: Hct 35 +/- 1.2%, Hb 12.1 +/- 0.6 g/dl, TSAT 29 +/- 10%, serum ferritin 204 +/- 98 ng/ml, sAlb 4.1 +/- 0.3 g/dl, Kt/V 1.33 +/-0.19, PCRn 1.11+/- 0.28 g/kg/day, weekly dose of rHuEpo 123 +/- 76 U/kg. Hct did not correlate with Kt/V, whereas rHuEpo dose and Kt/V were inversely correlated (r = -0.49; P < 0.0001). Multiple regression analysis with rHuEpo as dependent variable confirmed Kt/V as the only significant variable (P < 0.002). Division of the patients into two groups according to Kt/V (group A, Kt/V < or = 1.2; group B, Kt/V > or = 1.4), showed no differences in Hct levels between the two groups, while weekly rHuEpo dose was significantly lower in group B than in group A (group B, 86 +/- 33 U/kg; group A, 183 +/- 95 U/kg, P < 0.0001). CONCLUSIONS: In iron-replete HD patients treated with rHuEpo in the maintenance phase, Kt/V exerts a significant sparing effect on rHuEpo requirement independent of the use of biocompatible synthetic membranes. By optimizing rHuEpo responsiveness, an adequate dialysis treatment can contribute to the reduction of the costs of rHuEpo therapy.

Correction of metabolic acidosis increases serum albumin concentrations and decreases kinetically evaluated protein intake in haemodialysis patients: a prospective study.

BACKGROUND: Metabolic acidosis in haemodialysis (HD) patients increases whole body protein degradation while the correction of acidosis reduces it. However, the effects of the correction of acidosis on nutrition have not been clearly demonstrated. STUDY DESIGN: In this study we have evaluated the effects of 3 months of correction of metabolic acidosis by oral sodium bicarbonate supplementation on protein catabolic rate (PCRn) and serum albumin concentrations in 12 uraemic patients on maintenance HD for at least 6 months (median 49 months; range 6-243 months). Pre-dialysis serum bicarbonate, arterial pH, serum albumin, total serum proteins, serum creatinine, plasma sodium, haemoglobin, PCRn, Kt/V, and TACurea, were evaluated before and after correction. RESULTS: Serum bicarbonate levels and arterial pH increased respectively from 19.3 +/- 0.6 mmol/l to 24.4 +/- 1.2 mmol/l (P < 0.0001) and 7.34 +/- 0.03 to 7.40 +/- 0.02 (P < 0.0001). Serum albumin increased from 34.9 +/- 2.1 g/l to 37.9 +/- 2.9 g/l (P < 0.01), while PCRn decreased from 1.11 +/- 0.17 g/kg/day to 1.03 +/- 0.17 g/kg/day (P < 0.001). No changes in Kt/V, total serum proteins, serum creatinine, plasma sodium, haemoglobin, body weight, pre dialysis systolic and diastolic blood pressure, and intradialytic weight loss were observed. CONCLUSIONS: Our data demonstrate that correction of metabolic acidosis improves serum albumin concentrations in HD patients. The correction of acidosis induces a decrease in PCRn values, as evaluated by kinetic criteria, suggesting that in the presence of moderate to severe acidosis this parameter does not reflect the real dietary protein intake of the patients probably as a result of increased catabolism of endogenous proteins. The correction of metabolic acidosis should be considered of paramount importance in HD patients.

Evidence for an independent role of metabolic acidosis on nutritional status in haemodialysis patients.

BACKGROUND: Malnutrition in haemodialysis (HD) patients has been referred to underdialysis with low protein intake, and to acidosis. However, the separate effects of underdialysis and acidosis on nutrition have not been clearly demonstrated. To evaluate the role of the dialysis dose and of metabolic acidosis on nutrition, we measured the predialysis serum HCO3, pH, serum albumin, PCRn, Kt/V, and BMI in 81 uraemic patients on maintenance bicarbonate HD for 93+/-80 months. Patients with chronic liver diseases, malignancies, and cachexia were excluded. RESULTS: Mean age was 59+/-17 years, Kt/V was 1.29+/-0.21, PCRn 1.06+/-0.22 g/kg/day, serum albumin 4.07+/-0.28 g/dl, BMI 23+/-4 kg/m2, HCO3 21.1+/-1.9 mmol/l, pH 7.36+/-0.04. Serum albumin showed a significant direct correlation with: PCRn (P=0.001), HCO3 (P=0.001), pH (P=0.002), but no correlation with Kt/V and BMI. Serum HCO3 correlated inversely with PCRn (P=0.027). Multiple regression analysis confirmed the significant role of serum bicarbonate and age, but not of Kt/V, on serum albumin concentrations. The role of PCRn appeared to be marginal compared to serum bicarbonate in determining serum albumin levels. Dividing patients into two groups, serum albumin was 3.96+/-0.22 g/dl with HCO3 < or = 20 mmol/l and 4.18+/-0.31 g/dl in those with serum HCO3 > or = 23 mmol/l (P=0.002). PCRn in the same groups was respectively 1.14+/-0.24 g/kg/day and 1.01+/-0.23 g/kg/day (P=0.03). Most importantly, serum albumin levels did not appear to be affected by the dialysis dose, with Kt/V ranging from 0.90 to 1.88. CONCLUSIONS: In HD patients with adequate Kt/V, metabolic acidosis exerts a detrimental effect on serum albumin concentrations partially independently of the protein intake, as evaluated by PCRn. In the presence of moderate to severe metabolic acidosis, PCRn does not reflect the real dietary protein intake of the patients, probably as a result of increased catabolism of endogenous proteins. For this reason PCRn should be considered with caution as an estimate of the dietary protein intake in HD patients in the presence of metabolic acidosis.

Blood volume changes during three different profiles of dialysate sodium variation with similar intradialytic sodium balances in chronic hemodialyzed patients.

The aim of this study was to evaluate the effects on blood volume (BV) preservation of three different profiles of dialysate sodium variation with similar intradialytic sodium balances. Ten uremic patients aged 50 +/- 11 years receiving regular bicarbonate hemodialysis for 49 +/- 57 months were studied. Each patient underwent three hemodialysis treatments with different modalities of dialysate sodium profiles: constant sodium hemodialysis (CHD), high-low sodium hemodialysis (H-LHD), and low-high sodium hemodialysis (L-HHD). In CHD, the dialysate sodium concentration was 141 mEq/L and did not change during treatment. In H-LHD and L-HHD, the dialysate sodium concentration at the start of dialysis was 160 mEq/L and 133 mEq/L, respectively, and remained constant for 60 minutes. At this time, a single-step break point of variation of dialysate sodium concentration occurred. The dialysate sodium concentration changed according to a model aimed to keep identical the amount of dialysate sodium exchanged in the three different dialysis procedures. The duration of hemodialysis, the blood flow rate, the dialysate flow rate, and the dialysis membrane were the same for all three different hemodialysis modalities. The ultrafiltration rate was kept constant during treatment. Total dialysate collection and intradialytic sodium balance were calculated for each hemodialysis session. Blood pressure and heart rate were monitored at 10-minute intervals; percent reductions of BV (%R-BV) were continuously monitored by an online optical reflection method (Hemoscan; Hospal-Dasco, Medolla, Italy). The results have shown a lower intradialytic %R-BV with H-LHD compared with L-HHD and CHD. No differences in total ultrafiltration rate, systolic and diastolic blood pressures, and heart rate were observed among the three different dialysis procedures. The total dialysate sodium collected and the intradialytic sodium balances were very similar among the three different dialysis procedures, confirming the accuracy of the precision of the sodium model used. The H-LHD sodium profile may be a useful tool in the prevention of excessive %R-BV and of dialysis intolerance episodes.

CAPD viability: a long-term comparison with hemodialysis.

OBJECTIVE: To compare the long-term viability of continuous ambulatory peritoneal dialysis (CAPD) to that of hemodialysis (HD). DESIGN: Retrospective study of patients of our institution starting dialysis between January 1, 1981, and December 31, 1993, and surviving for at least 2 months. PATIENTS: Five hundred and seventy-eight new patients (51.3% on CAPD and 48.6% on HD). MAIN OUTCOMES STUDIED: Cox-adjusted assessment of patient and technique survival, and of technique success. Differences in results for two successive periods of time. RESULTS: Patient survival did not differ between CAPD and HD after adjusting for age and comorbidity, and significantly improved in the second part of the follow-up (1987-1993). Technique failure was significantly higher on CAPD, in which it was inversely related to age. The probability of a patient continuing on the first method of dialysis ("technique success") was significantly lower on CAPD than on HD, but the difference decreased progressively with age and disappeared in patients > or = 75 years. CONCLUSION: CAPD is as effective as HD in preserving life in uremic patients in the long-term, and gives better results in the older elderly. In adults, the lower technique success rate may not be a problem for patients with access to a good transplantation program; for others, this drawback must be weighed against the advantages of home treatment.

A prospective comparison of bicarbonate dialysis, hemodiafiltration, and acetate-free biofiltration in the elderly.

Hemodiafiltration (HDF) and more recently acetate-free biofiltration (AFB) have shown good blood purification and cardiovascular stability in young and middle-aged hemodialysis patients. It is not clear if this is also valid for elderly patients. Twelve patients aged more than 70 years (mean age +/- SD, 76 +/- 4 years) on regular dialysis for at least 5 months were treated with bicarbonate dialysis (BD), HDF, or AFB in a randomized sequence and prospectively followed for 6 months (72 dialysis sessions/patient) for each procedure. The dialysis solution (containing bicarbonate), blood flow rate, and dialysate flow rate were the same with all the methods. During HDF and AFB solutions containing bicarbonate at a concentration of 27 to 30 mEq/L and 145 mEq/L, respectively, were infused postdilution at a rate of 66 +/- 7 mL/min and 2.81 +/- 0.12 L/hr, respectively. During the period of observation we evaluated the number of intradialytic hypotensions, the episodes of nausea, vomiting, headache (dialysis intolerance), body weight, the interdialysis weight gain, the duration of the dialysis session, the number of hospitalizations/patient, and the length of hospitalization/patient. At the end of each observation period we determined: Kt/V, protein catabolic rate, acid base balance, serum creatinine, serum calcium, serum phosphorus, alkaline phosphatases, and serum intact parathyroid hormone. After the switch from BD to either HDF or AFB, the results have shown a significant reduction of dialysis hypotension episodes (18 percent on BD, 14 percent on HDF, and 13 percent on AFB; BD v HDF, P = 0.001; BD v AFB, P = 0.0001; and HDF v AFB, P = NS) and of dialysis intolerance (3.3 percent on BD, 1.3 percent on HDF, and 1.1 percent on AFB; BD v HDF, P = 0.021; BD v AFB, P = 0.019; and HDF v AFB, P = NS). Kt/V improved significantly after the switch from BD to either HDF or AFB (1.17 +/- 0.06 on BD, 1.32 +/- 0.12 on HDF, and 1.32 +/- 0.13 on AFB; BD v HDF, P = 0.021; BD v AFB, P = 0.003; HDF v AFB, P = NS). Protein catabolic rate also improved in HDF and AFB compared with BD (0.90 +/- 0.12 on BD, 1.03 +/- 0.15 on HDF, and 1.04 +/- 0.14 on AFB; BD v HDF, P = 0.001; BD v AFB, P = 0.009; and HDF v AFB, P = NS). AFB showed a better correction of acidosis compared either with BD or HDF (serum bicarbonate, 20.3 +/- 1.1 mEq/L on BD, 20.8 +/- 2.2 mEqL on HDF, and 22.2 +/- 2.4 mEq/L on AFB; BD v HDF, P = NS; BD v AFB, P = 0.01; and HDF v AFB, P = 0.030). The other parameters observed did not differ. In conclusion HDF and AFB show a better dialysis efficiency and a better hemodynamic tolerance compared with BD. This fact is associated with an improvement in protein intake as assessed by kinetic criteria. Acetate-free biofiltration has the further advantage of a better control of the acid-base balance compared with BD and HDF. HDF and AFB are useful dialytic options to traditional BD hemodialysis even in patients older than 70 years.

Comparison of long-term survival between hemodialysis and peritoneal dialysis.

We have reviewed the literature and our own center's results for patients on long-term continuous ambulatory peritoneal dialysis (CAPD) in comparison to results for patients on hemodialysis (HD). Contrary to recent American data showing one-year survivals to be worse on CAPD, the Canadian Registry and other studies show no significant difference in survivals on the two methods. Results are also conflicting for diabetics. Insufficient adjustments for age and case-mix variations are probably the most important causes for differences. For the general population, personal Cox-adjusted data show no difference between CAPD and HD up to ten-year follow-up, with very close curves for the adults and non-significant differences for the elderly. Old elderly (> 75 years) have better survival on CAPD in the first years of treatment. Dropout, which is higher on CAPD, decreases with age, and the patient retention on CAPD is worse than on HD for all patients, except the old elderly, for whom it is similar. These data were obtained in patients receiving a standard treatment, modified in order to give a more adequate dialysis dose only in recent years. The results of a prospective three-year study on the effect of nutritional [serum albumin and transferrin, normalized protein catabolic rate (PCRN), and subjective global assessment of malnutrition] and adequacy indices [Kt/V, creatinine clearance (Ccr), residual renal function] on patient survival on CAPD and HD are reported. Survival was not different for the two methods. Using the Cox analysis, nutritional indices did not affect survival whereas adequacy indices did. The effect of low serum albumin on survival was referable to the predialysis nutritional state. The similar survivals obtained on CAPD and HD, with Kt/V more or less than 1.0/treatment for HD and 1.7/week for CAPD, support the "peak concentration hypothesis" of Keshaviah et al. Survival in different groups of patients with different Kt/V and Ccr shows that the adequate dose on CAPD is Kt/V between 1.96 and 2.03 and Ccr > or = 70 L/week. A group of 26 patients who remained on CAPD treatment for more than eight years was also studied. Patient age and predialysis comorbidity were the most important factors affecting survival. Patients surviving longest had > 3 g/dL of serum albumin, > 0.8 g/kg/day of PCRN, a Kt/V > 1.6, and a weekly Ccr > 54L/week.

Predictive value of dialysis adequacy and nutritional indices for mortality and morbidity in CAPD and HD patients. A longitudinal study.

BACKGROUND: The effects of dialysis inadequacy on patient survival and nutritional status and that of malnutrition on survival have not been clearly assessed. Studies comparing dose/mortality and morbidity curves on continuous ambulatory peritoneal dialysis (CAPD) and on haemodialysis (HD) are also needed, to assess adequate treatment on CAPD. METHODS: We have evaluated the effects of age, 13 pretreatment risk factors, serum albumin, transferrin, normalized protein catabolic rate, Kt/V, normalized weekly creatinine clearance, residual renal function and subjective global assessment of nutritional status on survival and morbidity, in a 3-year prospective study of 68 CAPD and 34 HD patients. RESULTS: Survivals did not differ for CAPD and HD patients. In the Cox hazard regression model, age, peripheral vasculopathy, serum albumin < 3.5 g/dl and Kt/V < 1.0/treatment on HD and < 1.7/week on CAPD were independent factors negatively affecting survival. On the contrary, adjusted survivals were not affected by gender, modality, other comorbid factors, normalized protein catabolic rate, or subjective global assessment of nutritional status. Persistence of residual renal function significantly improved survival. Observed and adjusted survival did not significantly differ for CAPD and HD patients with either low (HD, < 1.0/treatment; CAPD, < 1.7/week) or high ( > or = 1.0 and > or = 1.7) Kt/V. On HD, adjusted survivals were similar for 1.0 < or = Kt/V < 1.2 or > or = 1.2. On CAPD, Kt/V > or = 1.96/week was associated with definitely better survival, with only one death/23 patients versus 19/45, with Kt/V < or = 1.96. Survival was not different for 1.96 < or = Kt/V < 2.03 and > or = 2.03. Normalized weekly creatinine clearance and wKt/V were positively related on CAPD (r 0.39, P < 0.01) and wKt/V = 1.96 corresponded to 58 litres of normalized weekly creatinine clearance. CONCLUSIONS: Indices of adequacy were predictors of mortality and morbidity, both on CAPD and HD, whereas normalized protein catabolic rate and subjective global assessment of nutritional status were not. Serum albumin did not decrease during dialysis; hence its predictive effect for survival is due to the predialysis condition and not to dialysis-induced malnutrition.

Which treatment for which patient in the future? Possible modifications in CAPD.

On 578 unselected new patients followed from 1981 through 1993, 51% on CAPD and 49% on HD, long-term patient and method survivals, cause of death, and drop-out in the two methods were compared. Survival, adjusted for patient selection biases, was not different on CAPD and HD up to 10 years. 50% of the patients were still in their first treatment after 3.5 years on CAPD and after 7 years on HD, and 5 and 28% respectively, after 10 years. Patient survival on CAPD was not falsely improved by drop-outs. Drop-out is increasing for CAPD, mainly due to patient/partner burn-out, which should be relieved by a more liberal application of automated PD. Malnutrition is more frequent on CAPD than on HD but not for the elderly. In a 3 year prospective study on 60 CAPD and 34 HD patients serum albumin, nPCR and nutritional status, as assessed by SGA did not influence survival in each modality. Survival was similar with K(p,r)t/V > or = 1.7/week on CAPD and Kt/V > or = 1/treatment on HD, and worse below these values. On CAPD, a Kp,rt/V > or = 1.96 gave better survivals.

Low incidence of peritonitis with the T-set.

Peritonitis is still one of the most important complications of peritoneal dialysis. Over the last few years, many efforts have been made in developing new device systems. A remarkable improvement has been obtained by modifying the original connection between the catheter and the bag, especially after the introduction of the Y-set. The aim of this study was to verify whether the use of a new device system, called the T-set, could reduce the incidence of peritonitis. This connector adds the advantages of the Y-set to those of the twin bag. In a group of 53 patients enrolled in a three-year period with a follow-up of 797 patient-months, we observed an incidence of peritonitis of one episode every 50 months. Furthermore, in the subgroup of 39 new patients, we observed an incidence of peritonitis of one episode every 89 patient-months. This new device can be a further step in the evolution of connectors that reduce the incidence of peritonitis.

Simultaneous catheter replacement-removal during infectious complications in peritoneal dialysis.

The aim of this study was to verify whether the replacement of the peritoneal catheter in a single operation and during infectious complications of peritoneal dialysis is effective and safe. Sixty-eight infectious complications refractory to appropriate antibiotic therapy were treated by this technique: 26 tunnel infections, 22 peritonitis-complicating tunnel infections, 12 refractory peritonitis, and 8 recurrent peritonitis. Operations were successful in all cases of tunnel infection and recurring peritonitis, and in all cases but one of peritonitis-complicating tunnel infection. Ten failures occurred among the 12 catheters removed for refractory peritonitis. Microorganisms cultured in these 10 failures were: Fungi (3 cases), Mycobacterium (2 cases), Pseudomonas (2 cases), Acinetobacter (1 case), Acinetobacter+Pseudomonas (1 case), and Enterococcus (1 case). Complications were 3 one-way obstructions and 2 external dialysate leaks. This study supports the simultaneous catheter replacement-removal procedure during infectious complications of peritoneal dialysis (PD) with the exception of refractory peritonitis; this technique spares the patient the temporary vascular access, the shift to hemodialysis, and a second operation to insert a new catheter. There are few complications.

Morbidity and mortality of CAPD and hemodialysis.

We have reappraised studies on morbidity and mortality in continuous ambulatory peritoneal dialysis (CAPD), comparing it with hemodialysis (HD), the standard treatment for end-stage renal disease (ESRD). More hospitalization is required for CAPD, the difference being related to peritonitis, to the more frequent presence of some risk factors (such as diabetes and atherosclerosis) in the patients selected for CAPD, and to the lack of experience in the early years of CAPD practice. CAPD patients have less acute morbidity during treatment that not always requires hospitalization: hypotension, hypertension, arrhythmias, and myocardial ischemia. Cardiac performance is also better in CAPD patients, who develop less myocardial hypertrophy than HD patients. Hospitalization due to infectious disease not referable to technique, beta 2-microglobulin related morbidity, signs of uremic neuropathy, osteodystrophy, and malnutrition are similar in both groups. Method survival is better for HD, the difference being completely accounted for by peritonitis. Patient survival adjusted for pre-treatment differences is similar in CAPD and HD, and this is not an artifact of more drop-outs on CAPD. A high incidence of peritonitis is accompanied by an increased risk of death. Older patients have a lesser risk of death on CAPD than on HD. Diabetics have a worse survival than non-diabetics, with no difference between the two methods. Although patient survivals on CAPD and HD are the same, differences in the mode of blood purification have an interesting impact on particular aspects of morbidity.

In vitro and in vivo efficacy of a new connector device for continuous ambulatory peritoneal dialysis.

The purpose of this study was to evaluate the in vitro and in vivo efficacy of a new connection system for continuous ambulatory peritoneal dialysis (CAPD), called the T-set. With this system the patient wears a 27-cm extension line filled with Amuchina during the dwell time; the bag is made of a fill container linked to a drainage tube with a Y-shaped set. For bag exchange, only one connection is needed and this is subsequently flushed with the entire drainage volume. The in vitro efficacy of the system was tested with 20 sets filled with 10 mL of Amuchina and inoculated in the distal lumen with 2.1 x 10(3) colony-forming units (cfu) of S. aureus. After an incubation of 4-6 hours at 35-37 degrees C, three dialysate samples per set were collected, respectively, at the beginning of drainage and filling. All 120 samples were negative, whereas two control sets, filled with a phosphate-buffered saline, had positive drainage samples, and at least one positive infusion sample, indicating the efficacy of Amuchina in sterilizing the system under conditions simulating touch contamination. To evaluate the in vivo efficacy, safety, and acceptability of the T-system, a prospective randomized controlled trial was performed in seven centers: a control group (CG) of 56 patients (follow-up: 952.3 months, mean +/- SD: 17.0 +/- 7.8) was treated with a long branch (21 patients) or short branch (35 patients) Y-set and a test group (TG) of 66 patients (follow-up:898.1 months, mean +/- SD: 13.6 +/- 7.8) with the T-set.(ABSTRACT TRUNCATED AT 250 WORDS)

Hospitalization: CAPD versus hemodialysis and transplant.

We studied morbidity in 648 patients treated in our center in a ten-year period as indicated by duration of hospitalization: 232 patients were on CAPD, 188 on hemodialysis (HD) and 228 had cadaveric kidney transplants (Tx). Duration of hospitalization was divided into four groups according to its causes. The age of the patients on CAPD was 61 +/- 14 years, 53 +/- 17 on HD and 36 +/- 10 in the Tx group. The total follow-up was 629 patient-year (p-y) on CAPD, 458 p-y on HD and 928 p-y on Tx. The first admission was longer on CAPD (30 +/- 18 days) and on Tx (36 +/- 18 days) than on HD (18 +/- 12). After the first admission, the total days of hospitalization (days/patient-year, d/p-y) were more for CAPD than HD and Tx. Analysis of these data showed that the difference was due to peritonitis and to the different percentage of elderly patients in the CAPD group. With a reduction in the incidence of infectious complications (peritonitis, tunnel or exit-site), hospitalization in CAPD could be reduced to a length of time similar to that currently needed by HD and Tx patients. This can result in important cost-saving.

Nutritional status in long-term CAPD patients.

We studied normalized urea nitrogen appearance (NUNA), normalized protein catabolic rate (NPCR), and normalized daily creatinine excretion (NDCE) in twenty-one patients (15 men, 6 women; mean age 63 +/- 9 years) on CAPD for more than 4 years (80 +/- 27 months). In the same patients we evaluated the changes in serum albumin and transferrin with time. After 74 +/- 26 months on CAPD, NUNA was 0.12 +/- 0.03 g/Kg IBW/day, NPCR = 1.09 +/- 0.19 g/Kg IBW/day; NDCE = 15.1 +/- 3.1 mg/Kg IBW/day; serum albumin = 3.8 +/- 0.2 g/dl. NUNA was correlated with NPCR (p < 0.001) and both were correlated with NDCE (p = 0.007 and p = 0.008). NPCR significantly decreased as patient age increased (p = 0.007) but was not correlated with time on CAPD, sex or serum albumin. Serum albumin did not change as age increased. Serum albumin and serum transferrin had not significantly changed after 4 years (after 8 years in a subgroup of eight patients). Finally, we compared these data to the initial data recorded for the same patients (mean interval: 64 +/- 21 months). NUNA, NPCR and NDCE did not change significantly. Changes in NPCR were directly related to changes in NDCE (p = 0.019). This study supports that long-term CAPD does not necessarily impair nutritional status and suggests that the oldest patients can maintain stable serum albumin concentrations on lower protein intake than younger ones.

Audiological findings in elderly patients with chronic renal failure.

The audiological results of 46 patients (m/f 27/19, mean age; 57.4 +/- 11.1) with chronic renal failure (CRF) undergoing dialysis were compared with those of an age- and gender-matched control group (n = 25). Mean pure tone average from 0.5 to 8 kHz was about 15 dB higher in CRF patients than in control subjects. The ABR parameters of the test group were then contrasted with those recorded in a second control group (n = 47, m/f 26/21, mean age: 56.1 +/- 11.4) matched by age, gender and degree of hearing loss (HL). After assessing the normality of the groups by the usual criteria, using the data of a sample of normal young adults, the ABR were found to be abnormal in 23.9% of the controls and in the 39.13% of the CRF patients. Wave V, I-III, III-V and I-V delays were significantly shorter in the females of the control group; in the CRF group, only the V and the I-V delays were shorter in females. The only age-dependent effect was found in the CRF sample, in which older patients had significantly longer I-III IPLD. The degree of HL influenced the latency of the waves in both groups but only the I-V IPLD was longer in CRF patients with pronounced high tone loss. The most distinguishing feature between the effects of CRF plus ageing and those of normal ageing was the lengthening of the I-III IPLD in the test group. This finding is likely to reflect a subclinical disorder of the VIII nerve function that is a part of the axonal uremic neuropathy.