Ultrafiltration with icodextrins in continuous ambulatory peritoneal dialysis and automated peritoneal dialysis.

Icodextrins (Icos) produce constant linear ultrafiltration (UF). This effect allows Icos to replace glucose during long dwells in continuous ambulatory peritoneal dialysis [CAPD (nighttime)] and automated peritoneal dialysis [APD (daytime)]. However, the effectiveness of Icos in producing UF (IcoUF) is limited by lymphatic reabsorption, whose extent depends partly on posture and physical activity. This paper aims to assess whether the difference in posture and physical activity between daytime dwells in APD and nighttime dwells in CAPD affects IcoUF. Patients undergoing first treatment were retrospectively examined. Ten patients were on CAPD [4 males, 6 females; average age, 73.0 +/- 13.4 years; body surface area (BSA), 1.63 +/- 0.21 m2; total volume per day, 5.6 +/- 1.9 L], and ten were on APD (7 males, 3 females; average age, 67.7 +/- 9.8; BSA, 1.75 +/- 0.22 m2; total volume per night, 10.5 +/- 0.9 L). Ultrafiltration was assessed for seven consecutive days preceding a peritoneal equilibration test (PET) and collection of diuresis. In both groups, 3 patients had no diuresis, and the difference between CAPD and APD was not significant (625 +/- 762 mL vs 780 +/- 878 mL). Moreover, no significant difference was seen in 4-hour dialysate-to-plasma creatinine (D/P) between CAPD (0.65 +/- 0.12) and APD (0.64 +/- 0.05). Dwell times with Icos were shorter in CAPD than in APD (11.5 +/- 1.8 hours vs 14.8 +/- 0.5 hours, p < 0.0005), but the fill volume was not significantly different (1760 +/- 286 mL vs 1790 +/- 249 mL). Water excretion owing to diuresis and dialysis [total water excretion (TWE): 1619 +/- 497 mL CAPD vs 1762 +/- 736 mL APD] and dialytic UF (363 +/- 443 mL CAPD vs 748 +/- 479 mL APD), which is not linked to Icos, were not significantly different between the two groups. The IcoUF and the percentage of IcoUF to TWE were significantly higher in CAPD compared to APD [631 +/- 253 mL (44% +/- 27%) vs 234 +/- 215 mL (19% +/- 19%), p < 0.001 (p < 0.05)]. In conclusion, an upright posture and physical activity seem to produce less IcoUF in APD despite the longer dwell. These factors could, indeed, produce greater intraperitoneal pressure, resulting in increased lymphatic reabsorption during a daytime dwell.

Production of platelet-activating factor in patients with sepsis-associated acute renal failure.

BACKGROUND: Studies in experimental animals have suggested that platelet-activating factor (PAF) is a mediator of sepsis-associated acute renal failure (ARF). In the present study we have evaluated whether an increased concentration of PAF within circulation or urine of septic patients correlated with the worsening of renal function. METHODS: The concentration of PAF and selected cytokines (TNF, IL-1, IL-6, IL-8) was evaluated in blood and urine of 12 patients with septic shock and ARF for 4 consecutive days. RESULTS: The data obtained indicate that blood and urinary concentrations of PAF and of IL-1, IL-6 and IL-8 were significantly higher in septic patients than in controls subjects and in patients with chronic renal failure. The concentration of TNF was significantly increased only in urine. A significantly positive correlation was found among blood concentration of PAF and heart rate (r = 0.4193, P < 0.017), serum creatinine (r = 0.3671, P < 0.038), serum IL-6 (r = 0.5475, P < 0.005) and urine excretion of IL-8 (r = 0.3984, P < 0.044), whereas a negative correlation was present with the number of circulating platelets (r = -0.4285, P < 0.018). Moreover, a positive correlation among the concentration of PAF in urine and the serum concentration of IL-6 (r = 0.5654, P < 0.006) and urine excretion of IL-6 (r = 0.6589, P < 0.0008) and IL-8 (r = 0.6371, P < 0.0004) were found. CONCLUSIONS: These results demonstrate in humans during ARF associated with septic shock the production of PAF, a mediator that has been previously implicated in the pathogenesis of experimental endotoxin-induced shock and renal injury. The observation that blood and urinary concentrations of PAF correlated with some of the clinical and laboratory parameters related to the severity of ARF and sepsis suggests that PAF may contribute to the development of renal injury in septic patients.

Calculation of Kt/V and creatinine [correction of creatine] clearance in APD.

The calculation of Kt/V and creatinine clearance per 1.73 m2 of body surface area (CrCl/1.73 m2 of BSA) varies according to whether the post- or pre-nightly dialysis treatment (NDT) values of the serum urea (sUrea), serum creatinine (sCreat), and body weight (BW) parameters are used. The purpose of this paper is to determine the difference between Kt/V and CrCl/1.73 m2 of BSA, calculated using the pre- and post-NDT values, and any correlation of such differences with different automated peritoneal dialysis (APD) methods. We took into consideration patients on APD treated using the tidal method with four different techniques: NTPD (9 patients; no daytime dwell), NTPD-1 (12 patients; one daytime dwell of 4-7 hours), CTPD (10 patients; one daytime dwell), and CTPD-2 (8 patients; two daytime dwells). Body water (V) and body surface area (BSA) were calculated using the Watson and Du Bois formulas. The percentage difference between pre- and post-NDT using the various methods is not statistically significant, while all the post-NDT parameters are significantly lower than the pre-NDT parameters. Since this difference is greater for sUrea (8.8%) and V (1.1%) than for sCreat (4.1%) and BSA (0.8%), the nightly Kt/V variation (11.2%) is greater than the nightly CrCl/1.73 m2 of BSA variation (5.2%). These variations do not differ significantly among the various methods. For APD, therefore, increase is to be expected in the CAPD targets of 10% and 5% respectively for Kt/V and CrCl/1.73 m2 of BSA calculated using the post-NDT values of sUrea and sCreat and the pre-NDT value of BW.

[Insufficient correction of blood bicarbonate levels in biguanide lactic acidosis treated with CVVH and bicarbonate replacement fluids]. / Insufficiente correzione della bicarbonatemia nella acidosi lattica da biguanidi trattata con CVVH e liquido di reinfusione con bicarbonato.

BACKGROUND: In the course of Continuous Veno-Venous Hemofiltration (CVVH), bicarbonate buffer instead of lactate is suitable for the treatment of combined renal and hepatic failure and for patients suffering from lactic acidosis, type A or B, joined with acute renal failure (ARF). METHODS: We applied the CVVH buffered with bicarbonate for the treatment of two patients affected by ARF and severe lactic acidosis type B (due to biguanide intoxication) and we evaluated its ability to correct the acid-base balance. RESULTS: Clinical and laboratory data show that this technique, performed in standard conditions (plasma flow: 70 ml/min, ultrafiltration: 25 ml/min, bicarbonate concentration in the infusion fluid: 30 mEq/L), was inadequate to compensate for the high requirement of bicarbonate (approximately 280 mEq/hr during the first 6 hours of observation) and the severe metabolic acidosis, thus additional bicarbonate infusion was needed. CONCLUSIONS: In particular, from ascertained data and theoretical considerations, in the course of lactic acidosis caused by biguanide, in order to correct acidosis a positive balance of bicarbonate could be obtained only by means of a bicarbonate-based replacement fluid and of a continuous high flow hemofiltration, such as to assure an ultrafiltrate volume exceeding 150 ml/min.

[Systemic mucormycosis in dialysis: computed tomography picture and histologic lesions]. / Mucormicosi sistemica in dialisi: quadro tomografico e lesioni istologiche.

Mucormycosis (zygomycosis) is an uncommon mycosis which can be contracted from the environment and which is responsible for rhino-orbital, pulmonary, gastrointestinal, cerebral or disseminated infections. Severe immunodepression, such as that caused by leukemia, lymphomata and organ graft, or treatment by desferrioxamine, may predispose to pulmonary and systemic forms. In the present work the authors describe a case of systemic mucormycosis, with unfavourable outcome, which arose in a pediatric peritoneal dialysis patient, then transferred to hemodialysis, without evident predisposing factors. In particular they refer to the CAT reports and to lymphonodal and peritoneal histological lesions which allowed them to attain the diagnosis.

Compliance study in peritoneal dialysis using PD Adequest software.

Poor compliance in peritoneal dialysis (PD) is a significant cause of dropout and morbidity. PD Adequest software, which, through a mathematical model, predicts the effect of the dialysis prescription on the basis of the peritoneal transport, may be used to identify the noncompliant patient. Fifty patients from two dialysis centers, aged 65.9 +/- 1.5 years and on PD for 28.6 +/- 4.7 months, were studied. A peritoneal equilibration test (PET) was carried out and 24-hour urine and dialysate were collected. Total weekly creatinine clearance (CrCl, L/week/1.73 m2) was calculated, as well as the glomerular filtration rate [(GFR), mL/min, mean CrCl and urea nitrogen clearance (UNCI)]. The dialytic schedules used were then introduced into the program and the parameters were recalculated using the software model. Nine patients considered noncompliant from their case histories were used to assess the differences of reference between expected and measured values. The control group was significantly different from the noncompliant group in the percentage of the CrCl and the serum creatinine (sCR) differences. The noncompliance threshold value was calculated from the mean of the lower 95% confidence interval of the compliant group and the higher one of the noncompliant group (-5.3%) for CrCl and vice versa for sCR (+10%), which behaved to the contrary. Reassessing the patients, 11 (22%) were identified as probably noncompliant.

Normalization of protein equivalent of nitrogen appearance and dialytic adequacy in CAPD.

Caloric-proteic malnutrition is frequently encountered in peritoneal dialysis and is associated with an increased risk of morbidity and mortality. Our paper aims to assess any greater reliability of protein equivalent of nitrogen appearance (PNA) normalization to desirable body weight (dBW) compared to actual body weight (aBW) and resulting implications for the relationship between dialytic adequacy and protein intake in continuous ambulatory peritoneal dialysis (CAPD). We studied 36 patients on CAPD, 24 male and 12 female (aged 66.6 +/- 10.2 years, 24 +/- 29 months on dialysis), collecting dialysate and urine over 24 hours (126 samples) to calculate the PNA according to Randerson and the total weekly KT/V. The total body muscle mass (TBMM) was calculated by anthropometry and the dBW according to Metropolitan Life Insurance tables. Finally, PNA was normalized to aBW (aPNA, g/kg/day) and to dBW (dPNA, g/kg/day). Average aBW proved to be higher than dBW (66.0 +/- 11.1 vs 59.8 +/- 6.9 kg, p < 0.0001) and aPNA lower than dPNA (0.96 +/- 0.31 vs 1.08 +/- 0.3 g/kg/day, p < 0.005). Compared to aPNA, dPNA correlates better with both blood urea nitrogen (BUN) (R2 = 0.702 vs 0.614) and KT/V (R2 = 0.348 vs 0.306). The TBMM is higher in the group with dPNA > or = 1.0 vs < 1.0 g/kg/day (25.5 +/- 0.6 vs 23.1 +/- 0.7 kg, p < 0.02) while, paradoxically, it is lower in patients with aPNA > or = 1.0 vs < 1.0 g/kg/day (22.8 +/- 0.8 vs 25.4 +/- 0.6 kg, p < 0.01). The KT/V of the patients with dPNA < 0.8, 0.8-1.2 and > 1.2 g/kg/day proved to be different (1.52 +/- 0.06 vs 1.80 +/- 0.03 vs 2.04 +/- 0.04, p < 0.005). On analysis of the linear regression, dPNA = 1.0 and 1.2 g/kg/day corresponds to KT/V values of 1.7 and 2.05, respectively. We consider dPNA to be more suitable then aPNA for the correct assessment of protein intake, and a weekly KT/V of 1.7-2.05 as being sufficient to guarantee satisfactory dPNA.

Role of automated peritoneal dialysis within a peritoneal dialysis program.

We wished to assess the impact of automated peritoneal dialysis (APD) on the peritoneal dialysis (PD) program. From November 1981 to December 1993, 112 patients were started on hemodialysis (HD) as first treatment and 88 on PD [continuous ambulatory peritoneal dialysis (CAPD): 78, APD: 10]; respective average ages were 61 +/- 14 and 62 +/- 13 years. To December 1985, APD was used as first treatment of PD in 1/29 patients (3.4%), while subsequently, on the basis of a clinical and social-aptitude assessment protocol, it was used in 9/59 patients (15.2%) with PD indication and CAPD contraindications (work: 2 patients, partner required: 7 patients). Of the patients who interrupted CAPD, APD was used in 9/21 patients (reason: social aptitude, 28.6%; clinical, 71.4%). Technique survival after 5 years proved no different in HD versus PD (87% vs 82%, p = NS), whereas in HD versus CAPD it was different (87% vs 62%, p < 0.025). The incidence of peritonitis in APD and CAPD with the Y-set was comparable (1/37 vs 1/40 episode/patient-months), while germ distribution was different (p < 0.001) with Staphylococcus epidermidis prevailing in APD (59%). Based on our experience, APD may extend method acceptance criteria and reduce the technique dropout rate in PD; however, connection technique may need to be improved in order to reduce the risk of peritonitis from exogenous contamination.

Are serum albumin and cholesterol reliable outcome markers in elderly dialysis patients?

Albumin and cholesterol are considered reliable outcome markers in dialysis patients; their influence, however, may also be related to non-independent factors, such as age and presence of co-morbid conditions. The aim of the study was an analysis of four outcome markers, assessed at start of dialysis: age, high risk conditions, cholesterol and albumin levels. Data were obtained from the Piedmont Dialysis and Transplantation Registry (northern Italy, about 4,400,000 inhabitants, 21 dialysis centres, open acceptance since mid-1970s, 5661 patients on file at 31 December 1992). Prevalence of albumin and cholesterol in the normal range increases with age; in each age group prevalence in the range is higher in patients at high risk. However, influence of these biochemical parameters is evident also in no-risk cohorts, thus identifying a subgroup with poorer prognosis also in the population without any identified classic risk factor. The influence of albumin, more evident in the population studied compared with cholesterol, is reflected by impaired survival of low-albumin patients (age > or = 65 high risk at 1 year: 60.7% vs 76.6%, P = 0.0052; age > or = 65 non-high risk, at 1 year: 76.5% vs 90.7%, P = 0.0001). In conclusion, albumin and cholesterol, assessed at start of dialysis, are reliable outcome markers even in elderly patients, identifying, in this high mortality cohort, a subgroup with poorer prognosis. If and how their effect may be reversed by dialysis therapy remains to be assessed.

[The value of albumin and cholesterol blood levels as indicators of the risk of death in dialysis. Working Group of the Piedmont Registry of Dialysis and Transplantation]. / Il valore dei livelli di albuminemia e colesterolemia come indicatori del rischio di morte in dialisi. Gruppo di lavoro dell'RPDT.

In recent years, the availability of large epidemiological series allowed identification of biochemical outcome markers in the dialysis population. Interest towards albumin and cholesterol levels is motivated by their easy availability and by the presence of a strong short-term effect on mortality and morbidity. The aim of the study was an analysis of the relationship between albumin and cholesterol levels at start of dialysis and mortality (gross mortality and Kaplan Meier survival curves). Data were obtained from the Piedmont Regional Registry of Dialysis and Transplantation (Northern Italy Region, about 4,400,000 inhab, 20 Dialysis Centers, open acceptance since mid '70, yearly information on 100% of patients) in the period 1981-1990 (4734 patients on file). Only non diabetic patients with follow-up > = 1 month, who started treatment in the Region, were selected. Patients with renal function recovery were excluded. Albumin levels were dichotomized at 3.5 g/dl. Cholesterol was stratified into 3 levels (< 150, 150-250, > or = 300 mg/dl). The choice of dividing the study into 2 periods (1980-1985 vs 1986-1990) is due to the fact that 1984 has been the year of switch from acetate to bicarbonate dialysis. Prevalence of albumin and cholesterol under the normal range (22% and 15%) is low and rises with age and presence of high risk conditions. A a good correlation with the risk of death of these biochemical markers (stronger for albumin at least in the short term) was observed. No correlations are found with risk of death and elevated cholesterol levels (low number of cases).(ABSTRACT TRUNCATED AT 250 WORDS)

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)

Role of alpha 1-proteinase inhibitor in restraining peritoneal inflammation in CAPD patients.

The concentration and functional state of alpha 1-proteinase inhibitor (alpha 1-PI) may modulate the expression of peritoneal phlogosis by affecting the activity of proteases and synthesis of autacoids. alpha 1-PI is detectable in peritoneal effluents of peritonitis-free patients. alpha 1-PI purified from peritoneal fluid of these patients was biologically active both in terms of inhibition of elastase activity and of synthesis of platelet activating factor (PAF). The biological activity of alpha 1-PI could therefore explain the absence of detectable amounts of PAF in peritonitis free patients despite the presence of intraperitoneal concentrations of tumor necrosis factor-alpha (TNF alpha) that would be sufficient per se to induce the synthesis of PAF. In patients with acute infectious peritonitis, the concentration of immunoreactive alpha 1-PI was significantly increased in respect ot stable patients. However, alpha 1-PI purified from patients with acute peritonitis was functionally inactive both on proteolytic activity on elastase and on TNF alpha-induced PAF synthesis by purified human PMN. The loss of alpha 1-PI activity correlated with the number of peritoneal leukocytes and was probably dependent on oxidative inactivation. Indeed, treatment with reducing agent restored the inhibitory function of alpha 1-PI. The inactivation of alpha 1-PI in patients with peritonitis was associated with the presence of PAF in peritoneal dialysates. These results suggest that alpha 1-PI prevents the proteolytic action and cell activation leading to PAF synthesis in peritonitis free patients. However, inactivation of its function by oxidants generated during the inflammatory process may lead to proteolytic injury and unrestrained synthesis of inflammatory mediators during peritonitis.

Intraperitoneal administration of phosphatidylcholine improves ultrafiltration in continuous ambulatory peritoneal dialysis patients.

Reports in the literature have linked a low phosphatidylcholine content in continuous ambulatory peritoneal dialysis (CAPD) effluent to ultrafiltration loss. Clinical evidence suggests that adding phosphatidylcholine to the dialysis solution enhances ultrafiltration. A clinical study has been designed to clarify the effect of phosphatidylcholine on ultrafiltration in CAPD patients with normal ultrafiltration. A weekly measurement of the peritoneal equilibration test was conducted per patient in the hospital. A comparison between the control dialysis solution (three-week period) and the phosphatidylcholine premixed solution (three-week period) was performed on a total of 12 patients. This study shows that a phosphatidylcholine premixed dialysis solution significantly enhances ultrafiltration. Since ultrafiltration per osmotic driving force (mL/g glucose) is enhanced, the patient's glucose load per day is reduced to achieve equal ultrafiltration. In the presence of phosphatidylcholine, peritoneal permeability remained unchanged, as indicated by membrane transport characteristics. No side effects were observed.

[Evaluation of nutritional status in a group of patients undergoing CAPD]. / Valutazione dello stato nutrizionale in un gruppo di pazienti in CAPD.

The onset of a protein-energy malnutrition represents a real risk for patients on CAPD. In order to verify the nutritional status and the effectiveness of the dietetic surveillance in preventing this complication, dietary intake, anthropometric measurements and biochemical parameters were monitored in 46 patients (27 males, 19 females, mean age: 58.7 +/- 14.8 years), suffering from ESRF and treated with CAPD, for a total observation period of 1731.67 months (mean: 37.64 +/- 25.17 months). The mean glucose concentration in the dialysate was 2.00 +/- 0.36 g/dl, the glucose reabsorption from dialysate per kg of ideal body weight (kg-IBW) was equivalent to 5.1 kcal, the mean dialysate protein loss was 13.08 +/- 5.52 g/day and the incidence of peritonitis episodes was 1 every 30.38 months-patient. The daily total caloric intake (by mouth and dialysate) was 30.8 kcal/kg-IBW with a normal subdivision for each diet component: there were not statistically significant differences in distribution according to age, sex and in the follow-up. The mean daily value of protein intake (PI) evaluated by dietary interviews was 0.99 g/kg-IBW, with a significant increase 1 year since the beginning of CAPD; the PI evaluated from urea nitrogen appearance was 1.22 g/kg-IBW. The PI remained stable later in the follow-up and in patients that made use of dietetic supplements, the mean daily increase by this way was 0.47 g/kg-IBW. Anthropometric measurements showed a statistically significant increase of %RBW after 1 year and of TS and % body fat after 3 years.(ABSTRACT TRUNCATED AT 250 WORDS)

[CAPD versus hemodialysis. 7 years' experience at the Centro Dialisi in Alba]. / CAPD versus emodialisi. Sette anni di esperienza del Centro Dialisi di Alba.

The purpose of the study is to compare the survival of the patients and the drop-out for change of the method in 2 groups of patients (pts) undergoing either CAPD (41 pts) or standard hemodialysis (HD) (45 pts) as first treatment, since November 1981 to August 1988. Distribution per sex (24 males and 17 females in the CAPD group vs 32 males and 13 females in the HD group), mean age (61.3 years vs 56.7) and number of risk factors (57 vs 61) were not significantly different. The total period of observation was significantly higher (1305.8 months vs 780.3, P less than 0.01) and the results seemed to be better in the CAPD group, but the life table analysis showed no significant differences in the incidence of death (10 events vs 13) and of drop-out for change of the method (8 events vs 10) respectively in the CAPD and in the HD group. At the end of the study 51.2% of pts on CAPD and 33.3% on HD were still on first treatment; clinical problems (respectively 62.5% and 70.0%) were the most frequent cause of drop-out. The Authors conclude that CAPD in the medium-term is a valuable method of treatment of end-stage renal failure, competitive with standard HD when patient selection is not biased by a negative selection.