Anemia and secondary hyperparathyroidism.

Anemia has been recognized recently as a possible complication of primary hyperparathyroidism. If the hyperparathyroid state can induce anemia in patients with normal kidney function, the extremely high levels of circulating parathyroid hormone usually observed in hyperparathyroidism secondary to chronic renal failure may have an unfavorable influence on the anemia of uremic patients. We investigated the influence of subtotal parathyroidectomy on the severity of the anemia of 18 uremic subjects undergoing long-term hemodialysis therapy. Subtotal parathyroidectomy resulted in a significant increase of mean hematocrit value. RBC count, and hemoglobin level. Serial bone biopsies suggested a relationship between the amount of marrow fibrosis and the improvement of anemia after surgery, but the precise mechanism of this phenomenon is still unknown.

Accumulation of 5 alpha-reduced androgen glucosiduronates associated with impaired removal in young male hemodialysis patients.

Hypothalamic-pituitary gonadal function is commonly altered in dialysis patients. Even though an improvement in general status and well-being has been noted after recombinant human erythropoietin supplementation, no significant changes were observed in the sex hormone profile. Pituitary gonadal axis as well as 5 alpha-reduced androgen glucosiduronates (i.e. 5 alpha-androstane,3 alpha,17 beta-diol and androsterone) profiles were studied in 23 young male stable dialyzed patients and compared to an age-matched group of healthy subjects. 5 alpha-Reduced androgen glucosiduronates are products of peripheral testosterone (T) metabolism and seem to be a useful tool in assessment of the male androgen status. Their polarity facilitates their urinary excretion, and their clearance is similar to the glomerular filtration rate in healthy men. We observed 1) a pituitary-Leydig cell dysfunction supported by normal serum estradiol and T levels, low free T, and increased LH levels; 2) an alteration of the dehydroepiandrosterone (DHEA) sulfate-DHEA interconversion, reflected by a dramatic decrease in DHEA while DHEA sulfate levels remained in the normal range; 3) an accumulation of 5 alpha-reduced androgen glucosiduronates, whose removal was impaired as shown by their very low sieving coefficients (< 0.012). Taken together, the above observations are consistent with alteration of spermatogenesis with respect to dialysis duration in which earlier elevated baseline serum LH levels indicate a primary defect in Leydig cell function.

The estimation of whole blood viscosity by a porous bed method.

A significant impediment in determining the relative contribution of whole blood viscosity to the pathogenesis of cardiovascular and cerebrovascular disease has been the lack of an uncomplicated method to measure whole blood viscosity. To address this problem, a simplified porous bed viscometer has been developed to measure whole blood viscosity. Whole blood is passed through a porous bed of branching channels with a mean pore diameter of 69.6 +/- 20.2 microns and an estimated mean shear rate of 19.6 seconds-1. The effects of sample collection, sample storage, and temperature are described. The mean whole blood viscosity of 242 healthy persons was 22.7 +/- 5.3 seconds, which, when corrected to centipoise using Darcy's equation, corresponds to an apparent viscosity of 5.7 +/- 1.3 cp. There was a significant difference in the whole blood viscosity of normal men and women related to their different packed cell volumes. Platelets and granulocytes influenced whole blood viscosity in proportion to their contribution to the total packed cell volume. Fibrinogen levels did not significantly influence measured whole blood viscosity, which is consistent with the disaggregating conditions and the mean shear rate of the instrument. The porous bed viscometer is a convenient means to measure whole blood viscosity and it should be useful as a screening test for clinical and epidemiologic studies.

Combined nutritional support and continuous extracorporeal removal therapy in the severe acute phase of maple syrup urine disease.

OBJECTIVE: The authors assessed the efficiency, tolerance and outcome of neonates and children with maple syrup urine disease (MSUD) in acute decompensation managed by endogenous and extracorporeal removal of accumulated MSUD metabolites. DESIGN: Single center cohort study. SETTING: Pediatric and neonatal intensive care unit in a tertiary care hospital. PATIENTS: Between January, 1991, and June, 1999, six neonates and six children in acute decompensation of MSUD were included in the study. Each of them had two of the three following criteria: comatose state, gastrointestinal intolerance, leucine plasma levels over 1700 micromol/l. INTERVENTIONS: Patients were treated by combined nutrition manipulation and continuous venovenous extracorporeal removal therapies (CECRT) including hemofiltration, hemodialysis or hemodiafiltration. A clinical and biological evaluation was performed before, during and following the treatment. RESULTS: Eleven out of the 12 patients survived. One child had two acute episodes at 6.5 and 9 years old. Eight patients recovered a normal cerebral performance category score. In all cases, plasma leucine level decreased according to a logarithmic mode within 11-24 h hemodiafiltration combined with nutritional support whereas, with nutrition alone after stopping CECRT, the decrease in leucine plasma levels was slower, following a linear mode. Eight patients were supplemented with valine and isoleucine for mean plasma values of 177+/-92 and 68+/-66, respectively. CONCLUSION: In severe acute decompensation of MSUD, CECRT combined with nutritional support limit central nervous system damage, by dramatically decreasing branched chain amino and keto acid levels.

Kinetics of technetium-labeled heparin in hemodialyzed patients.

Technetium-labeled heparin kinetics studies were undertaken in 12 hemodialyzed patients, where heparin was used over a long term (1 to 10 years) for anticoagulation of the extracorporeal circuit. The 99mTc-heparin (99mTc VECTOSCINT, Solabco Nuclear, Coutras, France) used has a 10 mCi activity and a labeling efficiency of more than 95%. Two healthy subjects served as control. After an i.v. bolus of 2 ml 99mTc-heparin, corresponding to 170 +/- 10 IU, radioactivity of kidney, liver, knee and shoulder was recorded with a gamma camera at t1-h, t3-h and t6-h during 120, 152 and 215 s, respectively. Radioactivity recorded was computerized, giving quantitative data for comparison. In hemodialyzed patients, accumulation of radioactivity (mean +/- SEM 10(6) x activity count) was significantly higher at the knee (11.3 +/- 1.1 vs. 4.9 +/- 0.4; p < 0.05; 13.4 +/- 1.1 vs. 5.7 +/- 0.7; < 0.02; and 14.7 +/- 0.8 vs. 5.3 +/- 0.6; < 0.001), and on the shoulder (17.3 +/- 1.1 vs. 10.7 +/- 1.4; p < 0.05; 19.9 +/- 1.0 vs. 10.9 +/- 1.7; < 0.01; 20.8 +/- 1.1 vs. 10.1 +/- 0.9; < 0.01) at t1-h, t3-h and t6-h, respectively, than in control subjects at the same areas. Although direct evidence is not in hand, accumulation of heparin in bone tissue due to renal excretion failure could play a role in mineral metabolism resulting in osteopenia in hemodialyzed patients.

Detrimental effects of late referral in patients with chronic renal failure: a case-control study.

Despite broader indications and easier access to renal replacement therapy during the past decades in Western countries, an unduly high number of patients is still referred to maintenance hemodialysis (HD) at a very advanced stage of chronic renal failure (CRF). To assess whether such late referral induces detrimental effects, we retrospectively compared clinical status and laboratory features in 20 patients who had been referred to us less than one month prior to first HD (late referral, or LR group) and in 20 sex- and age-matched controls who had undergone regular follow-up for at least six months prior to HD (early referral, or ER group). Male to female ratio was 12/8 and age averaged 53.5 years in both groups. Mean (+/- 1 SD) systolic and diastolic blood pressure were higher in LR group than in controls (180 +/- 14/102 +/- 10 vs. 153 +/- 15/86 +/- 7 mm Hg, P < 0.001) and fluid overload with pulmonary edema was present in 13/20 versus 3/20 patients (P < 0.001). Plasma concentrations (mmol/liter) of creatinine (1.12 +/- 0.27 vs 0.97 +/- 0.11, P < 0.01) and phosphate (2.58 +/- 0.47 vs. 1.92 +/- 0.31, P < 0.001) were higher, whereas plasma levels of bicarbonate (14.2 +/- 3.9 vs 22.5 +/- 4.2, P < 0.001) and calcium (1.85 +/- 0.24 vs. 2.27 +/- 0.15, P < 0.001) were lower in LR than in ER group, as were hemoglobin (7.1 +/- 1.1 vs. 9.4 +/- 0.9 g/dl, P < 0.001) and serum albumin levels (35.3 +/- 4.8 vs. 39.7 +/- 3.4, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Urea rebound and residual renal function in the calculation of Kt/V and protein catabolic rate.

Kt/V-urea and protein catabolic rate (PCR) are used for dialysis prescription and evaluation of protein intake of patients on regular dialysis treatment. The study was undertaken to determine the implication of urea rebound and residual renal function (RRF) on the calculation of Kt/V-urea and PCR for 61 patients. Kt/V-urea and PCR were calculated, implementing or not urea rebound at one hour after the end of dialysis session. Urea and creatinine rebound rate in patients without RRF was significantly higher than in patients with RRF (P < 0.05). In patients without RRF, creatinine generation rate and Kt/V-urea calculated without rebound were significantly higher than calculated with rebound (P < 0.001). On the contrary, calculation of urea generation and PCR is not affected by these parameters. It is concluded that: (1) Rebound rate magnitude of urea and creatinine is dependent on solute molecular weight, RRF and probably on dialysis duration, whereas rebound rate magnitude of phosphorus is not affected, and (2) Rebound should be taken into account in the calculation of Kt/V-urea and creatinine generation rate in patients without RRF, otherwise, they would be overestimated.

[Treatment of chronic kidney failure by the keto-analogs of essential amino acids: 4 years' experience]. / Traitement de l'insuffisance rénale chronique par les céto-analogues des acides aminés essentiels: une expérience de 4 ans.

From June 1981 to June 1985, 22 patients with advanced chronic renal failure were treated with a preparation of ketoanalogues of essential amino acids (Ketosteril, 1 tablet/5 kg/day) combined with a protein supply of 0.4 g/kg/day. At the beginning of treatment, their mean plasma creatinine was 762 +/- 135 mumol/l and their creatinine clearance, 8.4 +/- 3.1 ml/min/1.73 m2. By the end of November, 1985, among the 20 assessable patients, 4 had been on ketoanalogues for 8 to 52 months, 9 had to be dialyzed after 4 to 20 months, 5 had died and 2 had abandoned treatment. A mean 28% decrease in plasma urea level and daily urinary urea output was observed after 1 month on ketoanalogues, and a sustained reduction in plasma creatinine was observed in 12 patients. Mean renal survival was 15.6 +/- 12 months (median: 12 months), and was longer in patients whose plasma creatinine was lower than 700 mumol/l at the beginning of treatment. The ketoanalogues were well tolerated, and no denutrition occurred. Our experience confirms the usefulness of this therapeutic approach in uremic patients and suggests that the best results would be obtained if ketoanalogues were introduced before end-stage renal failure.

[Incidence of end-stage renal disease in Ile de France: a prospective epidemiological survey]. / Incidence de l'insuffisance rénale terminale en Ile de France: enquête épidémiologique prospective.

OBJECTIVES: To evaluate incidence and prevalence of patients with end-stage renal disease (ESRD) treated with maintenance dialysis in the Ile de France district in 1998. METHODOLOGY: Prospective epidemiologic inquiry with the cooperation of the 91 nephrology departments and dialysis facilities of the Ile de France district (total population: 10,695,300 inhabitants in March 1999), from January 1st to December 31st, 1998. Evaluation of the demographic and clinical characteristics of the 1155 patients accepted on maintenance dialysis in 1998, and recording of the total number of dialyzed patients at the beginning and at the end of the same year. RESULTS: The total number of ESRD patients was 1155, including 29 (2.5%) children aged < or = 17 years and 86 (7.4%) returns to dialysis following kidney graft failure. Incidence of ESRD in first-dialyzed patients was 100/million/year and overall incidence, including returns from transplantation, was 108/million/year. Mean age of the 1040 adult first-dialysis patients was 59 +/- 16.8 years, with a proportion of those aged > or = 75 years of 21.6%. Patients with vascular renal disease were 22.5% and those with diabetic nephropathy 20.6%. As a whole, 36.5% of patients were referred to the nephrologist < 6 months of starting dialysis. Prevalence of patients on supportive dialysis increased from 417 to 433 per million inhabitants (a 3.8% increase) from the beginning to the end of 1998, with the proportion of patients treated with self-care dialysis or peritoneal dialysis rising by 10%. From January 1995 to January 1999, prevalence of dialysis-treated ESRD patients rose by nearly 4% per year as a mean. CONCLUSION: Incidence of ESRD patients requiring maintenance dialysis in the Ile de France district reached 100/million in 1998, an increment of 4% per year over the past 4 years. The increase in incidence results from the increasing number of older patients, parallel to the ageing of general population, these patients having a high comorbidity mainly due to diabetes and atherosclerosis. Prevalence of dialysis-treated patients was 433/million population at the end of 1998. It rose at a similar rate as did incidence, although with a growing proportion of out-center dialysis.

[Benefits of early nephrological management in chronic renal failure]. / Bénéfices d'une prise en charge néphrologique précoce de l'insuffisance rénale chronique.

OBJECTIVES: We evaluated whether early nephrological referral of patients with chronic renal failure (CRF) resulted in improved condition of patients at initiation of maintenance dialysis and in better outcome on dialysis. PATIENTS AND METHODS: We prospectively recorded clinical status, laboratory parameters, length of hospital stay and outcome of 900 CRF patients who started maintenance dialysis at Necker hospital between January 1989 and December 1996. We compared patients who benefited regular nephrological follow-up, and patients who were referred in emergency conditions at the ultimate stage of CRF. RESULTS: Among the 900 patients, 731 (81.2%) had regular nephrological follow-up, including 632 (70.2%, group IA) with optimal preparation to dialysis and 99 (11%, group IB) whose clinical course was complicated due to heavy comorbidity, whereas 169 (18.8%, group II) had no previous nephrological management. Over the 8-year observation period, the proportion of the latter group did not decrease. Late referred patients had higher blood pressure level, more frequent fluid overload, higher serum levels of urea, creatinine, uric acid and phosphate, and lower levels of bicarbonate, calcium, albumin and creatinine clearance that did well-prepared patients. Mean (+/- SD) hospital stay was 29.7 +/- 15.8 days in the former compared to only 4.8 +/- 3.3 days (p < 0.001) in the latter. Early deaths within 3 months of dialysis initiation were more frequent (7.1 vs 1.6%, p < 0.05) and less patients subsequently were able to be treated out-center (20.1 vs 40.7%, p < 0.05) in group II than in group IA. The overcost induced by late referral may be estimated at 0.25 million French francs per patient. CONCLUSION: An unjustified late nephrological referral of CRF patients still is observed in nearly 20% of cases. Such late referral is detrimental to both patients in terms of altered quality of life and long hospital stay, and to the collectivity due to heavy overcost. Closer cooperation between family physicians and nephrologists is needed to provide optimal management and allow timely preparation to maintenance dialysis of CRF patients.

[Benefits of early nephrological management of chronic renal failure]. / Bénéfices d'une prise en charge néphrologique précoce de l'insuffisance rénale chronique.

OBJECTIVES: We evaluated whether early nephrological referral of patients with chronic renal failure (CRF) resulted in improved condition of patients at initiation of maintenance dialysis and in better outcome on dialysis. PATIENTS AND METHODS: We prospectively recorded clinical status, laboratory parameters, length of hospital stay and outcome of 900 CRF patients who started maintenance dialysis at Necker hospital between January 1989 and December 1996. We compared patients who benefited regular nephrological follow-up, and patients who were referred in emergency conditions at the ultimate stage of CRF. RESULTS: Among the 900 patients, 731 (81.2%) had regular nephrological follow-up, including 632 (70.2%, group IA) with optimal preparation to dialysis and 99 (11%, group IB) whose clinical course was complicated due to heavy comorbidity, whereas 169 (18.8%, group II) had no previous nephrological management. Over the 8-year observation period, the proportion of the latter group did not decrease. Late referred patients had higher blood pressure level, more frequent fluid overload, higher serum levels of urea, creatinine, uric acid and phosphate, and lower levels of bicarbonate, calcium, albumin and creatinine clearance that did well-prepared patients. Mean (+/- SD) hospital stay was 29.7 +/- 15.8 days in the former compared to only 4.8 +/- 3.3 days (p < 0.001) in the latter. Early deaths within 3 months of dialysis initiation were more frequent (7.1 vs 1.6% p < 0.05) and less patients subsequently were able to be treated out-center (20.1 vs 40.7%, p < 0.05) in group II than in group IA. The overcost induced by late referral may be estimated at 0.25 million French francs per patient. CONCLUSION: An unjustified late nephrological referral of CRF patients still is observed in nearly 20% of cases. Such late referral is detrimental to both patients in terms of altered quality of life and long hospital stay, and to the collectivity due to heavy overcost. Closer cooperation between family physicians and nephrologists is needed to provide optimal management and allow timely preparation to maintenance dialysis of CRF patients.

[The future of hemodialysis in the adult]. / Les perspectives de l'hémodialyse de l'adulte.

By the year 2000, the perspectives for hemodialysis performed in adults will be oriented towards facilitation of the practice of hemodialysis as a better control of clinical symptoms observed in end stage renal failure treated by hemodialysis. Blood access is the main problem which remains to be solved. The authors describe the advantages and disadvantages of the methods presently used and give the "state of the art" of "blood access" prosthesis. Almost all symptoms encountered in renal failure patients treated by hemodialysis can be efficiently treated. Hypotensive drugs usually reduce hypertension which resists adequate treatment by hemodialysis. Most of the symptoms of osteodystrophy can be avoided by adequate diet associated with the prescription of vitamin D analogs. Nevertheless, the prolongation of hemodialysis treatment duration over 7 years has led to the apparition of destructive arthropathies which are very painful and handicapping. They are related to amyloid deposit of beta 2-microglobulins. Progress in hemodialysis technics and a better control of uremic symptoms allow application of this treatment at all ages of life. The authors examine specific problems concerning school-aged teenagers and aged persons. They show that results already achieved allow a daily treatment of these patients. This is a first step for the generalisation of this procedure to all patients and its advantages are described. Improvement of hemodialysis technics for the year 2000, as can be expected, mainly depends upon progress in knowledge of biocompatibility parameters between materials used in the artificial kidney and patients tissues, mainly blood vessels.

Initiation of dialysis: when?

Initiation of dialysis depends upon several parameters including medical and non-medical reasons. Among the medical parameters measured or calculated creatinine clearance from plasma creatinine concentration seems to be the most reliable factor although clinical parameters such as gastro-intestinal disorders, cardiovascular, hematological, neurological manifestations and last but not least general status of the patient tend to play a determinant role in the decision of initiating dialysis. Dialysis is usually initiated for patients with a normalized creatinine clearance of 5 ml/min.1.73 m2 but optional dialysis could be initiated from a normalized creatinine clearance of 10 ml/min.1.73 m2, in case the capability of the patient and the physician to tolerate the burden of uremic syndrome is overcome. Rather than employing dialysis too late, it now seems advisable to initiate dialysis earlier in the course of chronic renal failure. Actually, retrospective analysis of 167 over 625 cases records from 1981 to 1985 and of 178 over 700 case records from 1986 to 1990 in the Department of Nephrology, Necker Hospîtal, plasma creatinine concentration at initiation of dialysis of the two period was 1044 +/- 17 and 981 +/- 13 mol/L respectively, corresponding to a creatinine clearance of 6 and 7 ml/min. It is clear now that management of chronic renal failure patients should be considered as a whole and initiation of dialysis is the end point of this global strategy. Definitely, optimal time for initiating dialysis should take into account various parameters, both biological and clinical as well as associated parameters such as age of the patient and involved systemic disease.

Evaluation of parameters for adequate dialysis therapy: (1). Monitoring of parameters by urea kinetic modeling.

In an attempt to evaluate the adequacy of regular dialysis therapy, calculations of Kt/V-urea and protein catabolic rate (pcr) from the data of routine laboratory examinations by means of urea kinetic modeling were performed in 59 regular dialysis patients (28 males and 31 females; mean age, 59 +/- 2 years old; mean dialysis duration, 83 +/- 10 months). The mean values of Kt/V-urea and pcr were 1.10 +/- 0.04 and 0.98 +/- 0.03 g/kgBW.day, respectively. The number of patients who were within the optimal range (0.9-1.4 for Kt/V urea and 0.9-1.5 for pcr) was 37 (62.7%) for Kt/V-urea and 38 (64.4%) for pcr. Furthermore, we inferred that, based on an appropriate dietary protein intake, removal of urea by intermittent dialysis should be adjusted to maintain the patient in equilibrium for a defined pre-dialysis plasma urea concentration. From the data obtained, we concluded that: (1) it is possible to apply urea kinetic modeling on the basis of routine laboratory examinations, (2) it is important to maintain the pre-dialysis plasma urea concentration at more than a certain level, and (3) it is also important to control the post-dialysis plasma urea concentration at a low level.

Evaluation of parameters for adequate dialysis therapy: (2). Comparison between parameters according to UKM and other laboratory data.

Urea kinetic modeling (UKM) is often regarded as the best method for assessing the dialysis adequacy and consequently for the prescription of treatment time. However, other parameters are involved in the monitoring of end stage renal disease (ESRD) patients. Kt/V-urea and protein catabolic rate (pcr) were evaluated in 53 ESRD patients (25 males and 28 females; mean age, 60 +/- 2 years old; mean duration, 80 +/- 11 months), twice at an interval of 4 months, and pre-dialysis concentration of (pre-DC) plasma potassium, bicarbonate, calcium and phosphate were measured. The pre-dialysis systolic blood pressure and hematocrit were also recorded. The numbers of patients who were within the optimal range of Kt/V-urea and pcr recommended by Gotch and Sargent were 36 (67.9%) and 39 (73.6%), respectively, at the first control period, and 39 (73.6%) and 44 (83.0%) at the second control period. However, only about 50% of the patients were within the optimal range of pre-DC plasma calcium, phosphate and bicarbonate. Furthermore, very few patients fulfilled the conditions for all the parameters. It is concluded that (1) UKM is required to describe the domain of dialysis prescription, and (2) other parameters which are not dependent so much on dialysis should be taken into account for assessing the adequacy of dialysis.

The most suitable calculation of Kt/V-urea: Kt/V = ln(Ci/Cf).

Although various simplified calculation formulae of Kt/V-urea based on urea kinetic modeling have been reported, all the formulae include errors such as post-dialysis urea rebound and urea generation during a dialysis session. In the present study, in order to calculate the precise Kt/V-urea, a formula of Kt/V-urea, taking into account post-dialysis plasma urea rebound and urea generation during a dialysis session (Kt/V-P) was proposed, and compared to other formulae already published, in 49 dialysis patients without residual renal function (26 M and 23 F; mean age, 65 +/- 2 years; mean dialysis duration, 70 +/- 7 mos). The precise post-dialysis plasma urea concentration was significantly higher than the actually measured post-dialysis plasma urea concentration by approximately 12%, and Kt/V-P corresponded to Kt/V-urea = ln(Ci/Cf) with the best correlation in the formulae utilized in the present study, around 1 of Kt/V-urea, which is clinically the most important range. It is concluded that Kt/V-urea = ln(Ci/Cf) is the most suitable formula for the calculation of Kt/V-urea, when post-dialysis plasma urea rebound and urea generation during a dialysis session are taken into account.

[The clinical value of correction of acidosis by acetate-free biofiltration in patients on regular dialysis treatment].

Effects of metabolic acidosis were compared between bicarbonate dialysis (BCD) and acetate-free biofiltration (AFB). Three stable dialysis patients (1M, 2F, mean age 30 yrs) were selected for the study because their bicarbonate (BC) pre-dialysis plasma concentration were always under 16 mmol/l while they were on 33 mmol/l-BCD thrice weekly for 12 months. They were switched to a 6 months period of AFB. Pre- and post-dialysis BC plasma concentration, other blood chemical parameters and mass removal (total collection of used dialysate) of urea (U), creatinine (Cr), uric acid (UA), and phosphate (P) were measured during the last week of each period, including 3 dialysis sessions. Mean calorie and protein intake were 29.4 KCal/kg.d and 1.5 g/Kg.d (BCD period) and 38.2 Kcal/Kg.d and 1.5 g/Kg.d (AFB period) respectively. BC plasma concentration (Mean +/- SE, mmol/l) at the pre and post-dialysis in AFB were significantly higher than those in BCD (16.6 +/- 0.7 vs 20.8 +/- 0.6; p less than 0.001, 22.7 +/- 0.8 vs 25.8 +/- 0.8; P less than 0.02). Pre- and post-dialysis U plasma concentration (Mean +/- SE, mmol/l) in AFB were significantly lower than those in BCD (34.3 +/- 2.51 vs 20.8 +/- 0.59, 10.5 +/- 1.32 vs 7.5 +/- 0.92; P less than 0.001). Pre-dialysis P plasma concentration (Mean +/- SE, mmol/l) in AFB was significantly lower than that in BCD (1.85 +/- 0.09 vs 1.50 +/- 0.15; P less than 0.01). Cr, UA and P mass removal in BCD and AFB were not significantly different. However, U mass removal in AFB was significantly lower than that in BCD.(ABSTRACT TRUNCATED AT 250 WORDS)

Phosphate kinetics in acetate-free biofiltration.

The phosphate kinetics during bicarbonate dialysis (BCD) and Acetate-free Biofiltration (AFB) were determined in 3 stable regular dialysis patients. These patients were switched to a 6-month period of AFB after a 12-month period of BCD. The plasma levels of phosphate, urea, and bicarbonate, and mass removal of phosphate and urea were measured every hour, during 3 consecutive dialysis sessions on BCD and AFB. The plasma phosphate behavior revealed a peculiar form with two main components, which differed from that of urea. The plasma phosphate level fell sharply during the first 2 hours of treatment, and then remained at a plateau towards to the end of the session. The plasma bicarbonate levels during the treatment sessions in the case of AFB were significantly higher than that in BCD. The actual mass removal in AFB was similar to that BCD, despite a significantly lower value of pre-plasma phosphate. A high ultrafiltration rate and better control of acidosis might be the reason for the better performance of phosphate mass removal in AFB. Better control of phosphatemia due to AFB can lead to a reduction in the amount of phosphate binders which have several untoward side effects.

[Characteristics of artificial membranes]. / Caractéristiques des membranes artificielles.

The artificial membranes used in haemodialysis and haemofiltration are either cellulosic or made of synthetic polymers, such as polyacrylonitrile, polysulfone, polycarbonate, polymethylmetacrylate and ethyvinylalcohol. During dialysis the water and solute transfer primarily depends on hydraulic permeability and sieving coefficients. At present, high-flux membranes have sieving coefficients for urea (Mol. wt 60) to inulin (Mol. wt 5,200) that are similar to those of the glomerular basal lamina, whereas their hydraulic permeability remains well below that of the renal filter. Bioincompatibility factors responsible for acute, anaphylactoid-like reactions and chronic inflammatory complications have been identified. The choice of the correct dialysis membrane must rest not only on performance criteria but also on biocompatibility and economic criteria.

[Indications and preparations for kidney dialysis]. / Indication et préparation au traitement de suppléance rénale.

Every patient with end-stage renal failure, at any age and whatever the type of renal disease, is a legitimate candidate to maintenance dialysis. Contraindications are infrequent and based purely on medical considerations, such as profound and irremediable alteration of physical and/or mental condition. In patients regularly managed dialysis is decided electively on the basis of laboratory criteria in the absence of clinical uremic manifestations other than fatigue, anorexia or nausea. The most widely accepted criterion is a level of creatinine clearance estimated by the Cockcroft-Gault formula between 7 and 10 mL/min/1.73 m2. Psychological preparation of the patient to dialysis is essential and should not be delayed until the advanced stage. Medical preparation involves prophylactic vaccination against virus B hepatitis and creation of a native arteriovenous fistula when hemodialysis is the scheduled option. Every patient should receive in time clear and complete information on the various technical methods of dialysis, in order to allow him an informed choice.