Search PubMed⌕ Search

Biomedical subjects

B Charra

Publications and source records attributed to B Charra.

At least 37 records · Page 2Linked to original sources
PubMed2004

Role of sodium in dialysis.

The total amount of sodium present in the body conditions the extracellular compartment volume. In advanced renal failure and in dialysis the sodium balance becomes positive and the extracellular volume inflates. This leads to hypertension and to direct cardiac and vascular changes that explain for a large part the excessive cardiovascular morbidity and mortality in dialysis patients. Controlling body sodium content and extracellular volume allows to reduce hypertension, cardiovascular changes and to improve dialysis patients survival. This can be achieved by reducing the sodium input (low sodium diet and reasonably low sodium dialysate) and/or by increasing sodium output (ultrafiltration by convection in hemodialysis or hemofiltration and osmotic drive in peritoneal dialysis). The intermittent nature of hemodialysis (and hemofiltration) conditions the saw-tooth volume fluctuations that drove to conceiving and implementing the concept of a dry weight, corresponding to normal extracellular volume and blood pressure.

Blood Pressure↗
PubMed2003

Nutritional effects of carnitine supplementation in hemodialysis patients.

AIMS: Carnitine is involved in fatty acid metabolism and it is cleared by dialysis. As it plays a role in energy utilization and because malnutrition is a frequent complication of HD treatment, we studied the effects of carnitine supplementation on several nutritional parameters in HD patients. MATERIAL AND METHODS: The main selection criterion was a body mass index (BMI; body weight/(height)2) < 22 kg/m2. Fifty-three patients were enrolled to participate in this open and randomized study. For 6 months, 28 patients received 15 mg/kg of intravenous L-carnitine at the end of each hemodialysis (HD) treatment (Group A), the remaining 25 patients were controls (Group B). The measured parameters were the post-dialysis body weight, serum albumin concentration (nephelemetry), food intake assessed by a 3-day food questionnaire, nPNA (normalized protein equivalent of nitrogen appearance), creatinine generation, and anthropometry. RESULTS: Forty-five patients completed the study (Group A: 14 F/9 M, 66.7 years old; Group B: 11 F/11 M, 65.2 years old). At the beginning of the study, there were no differences between the groups for age, gender, HD duration, BMI, diabetes prevalence, plasma carnitine levels and measured nutritional parameters. 65.2% and 77.3% in each group were carnitine-deficient (plasma total carnitine level < 35 micromol/l). After 6 months of L-carnitine supplementation, none of the nutritional parameters had changed in either group, except that serum albumin concentration decreased in both groups. Dividing each group according to their respective median serum albumin concentrations, daily energy and protein intakes, creatinine generation or triceps skinfold thickness did not show any difference in the various nutritional parameters with or without carnitine supplementation. CONCLUSION: Carnitine supplementation, despite normalization of plasma carnitine levels, has no effect on the nutritional status of HD patients.

Adult↗
PubMed2002

Risk factor analysis for long-term tunneled dialysis catheter-related bacteremias.

Infection, mainly related to vascular access, is one of the main causes of morbidity and a preventable cause of death in hemodialysis patients. From January 1994 to April 1998 we conducted a prospective study to assess the incidence and risk factors of catheter-related bacteremia. One hundred and twenty-nine tunneled dual-lumen hemodialysis catheters were inserted percutaneously into the internal jugular vein in 89 patients. Bacteremia (n = 56) occurred at least once with 37 (29%) of the catheters (an incidence of 1.1/1,000 catheter-days); local infection (n = 45, 1/1,000 catheter-days) was associated with bacteremia in 18 cases. Death in 1 case was directly related to Staphylococcus aureus (SA) septic shock, and septicemia contributed to deaths in 2 additional cases. Catheters were removed in 48% of the bacteremic episodes. Treatment comprised intravenous double antimicrobial therapy for 15-20 days. Bacteriological data of bacteremia showed 55% involvement of SA. Nasal carriage of SA was observed in 35% of the patients with catheters. Bacteremic catheters were more frequently observed in patients with diabetes mellitus (p = 0.03), peripheral atherosclerosis (p = 0.001), a previous history of bacteremia (p = 0.05), nasal carriage of SA (p = 0.0001), longer catheter survival time (p = 0.001), higher total intravenous iron dose (p = 0.001), more frequent urokinase catheter infusion (p < 0.01), and local infection (p < 0.001) compared with non-bacteremic catheters. Monovariate survival analysis showed that significant initial risk factors for bacteremia were nasal carriage of SA (p = 0.00001), previous bacteremia (p = 0.0001), peripheral atherosclerosis (p = 0.005), and diabetes (p = 0.04). This study confirms the relatively high incidence of bacteremia with tunneled double-lumen silicone catheters and its potential complications. Possible preventive actions are discussed according to the risk factors.

Adult↗
PubMed2001

Diabetes mellitus in Tassin, France: remarkable transformation in incidence and outcome of ESRD in diabetes.

The incidence and prevalence of diabetes mellitus (DM) in the dialysis population in Europe, and more especially in France, have been lagging behind the impressive United States and Japanese rates. For a decade, things have been changing, and the incidence of DM in hemodialysis (HD) reached almost 40 in Tassin, France in 1999. The prevalence has followed the same trend but increased more slowly. The increase in incidence and prevalence is almost totally accounted for by type 2 DM explosive outbreak and development. The morbidity on dialysis (hypotensive episodes, hospitalization number, and duration) was significantly worse in diabetic patients (without difference between type 1 and 2) than in nondiabetic patients. The mortality rate was higher in diabetic patients than in nondiabetic patients (mean half-life 3 and 13 years, respectively), even after adjustment for age and comorbidity. The mortality rate was higher in type 2 than in type 1 (mean half-life 2.7 and 5.2 years, respectively), a difference which disappears when adjusting for age and comorbidity. Specific causes of death were different in diabetic and nondiabetic HD patients; in diabetics there was a six-fold higher cardiovascular (CV) and three-fold higher infectious mortality, but there was the same mortality from cancer. A strong difference was observed between type 1 and type 2 DM: in type 1 there was no increased infectious mortality and a moderately increased CV mortality compared with nondiabetic patients. Type 2 diabetic patients had a four-fold increased infectious and an eight-fold increased CV mortality. Altogether, the eruption of DM in our unit over the last decade has drastically increased the crude mortality, but the standardized mortality ratio using the USRDS mortality table remained unchanged, about 45 of expected mortality.

Adult↗
PubMed2001

Malnutrition in long-term haemodialysis survivors.

BACKGROUND: Long survival is now common in patients with end-stage renal disease owing to improvement in dialysis techniques and kidney transplantation. As malnutrition is commonly reported in dialysis patients, we evaluated the nutritional status of patients treated with haemodialysis (HD) for more than 20 years. METHODS: Ten patients (59.5 years old; 4F/6M; HD treatment for 304 months; group A) underwent an extensive nutritional examination and were compared to a control group of 10 patients treated with HD for an average of 51 months and strictly matched for age (58.6 years old), gender, and height (group B). The patients were treated on a similar basis (long-duration HD, cellulosic membranes, Daugirdas index >2). RESULTS: The body weight (BW) in group A had decreased gradually from the 11th year of HD treatment, whereas it had increased by an average of 1.9+/-4.4% since the beginning of the HD treatment in group B. The body mass index (BMI) was lower in group A (19.3 +/- 2.3 vs 21.4 +/- 2.8 kg/m(2); P = 0.05). The arm-muscle circumference (AMC), the arm-muscle area (AMA), and triceps skinfold (TSF) were lower in group A than in group B. The fat mass assessed with anthropometry (10.8 +/- 4.0 vs 14.8 +/- 4.2 kg) was significantly lower in group A. The deviation of actual BW from ideal BW (IBW) was significantly lower in group A than in group B (80.6 +/- 10.7% vs 89.6 +/- 9.0%; P = 0.028); The deviations of actual BW, TSF, and AMA from standard values of the NHANES II study were more marked in group A than in group B. On the other hand, daily energy and protein intakes (DEI and DPI) were identical in both groups and met the recommendations for dialysis patients when normalized to the actual BW. When normalized to the IBW, the DEI appeared low. Energy expenditure was not different between groups, and not different from the resting metabolism calculated from the Harris and Benedict formula. Average albumin, prealbumin, and IgF-1 were normal and not different between groups. Branched-chain amino acids (BCAA), and especially leucine, were correlated with BMI in group A but not in group B. Serum total and free carnitine were low in both groups. Three patients had ascorbic acid deficiency in group A but none in group B. CONCLUSIONS: Hence, despite adequate dialysis dose and protein intake, patients treated with HD for a long period of time became malnourished, whereas the classical nutritional markers remained in normal ranges. Among the potential causes leading to malnutrition, inadequate energy intake and micronutrient deficiencies were found in these patients.

Aged↗
PubMed2001

Long-term outcome of permanent hemodialysis catheters: a controlled study.

AIMS: Hemodialysis tunneled catheters are widely used nowadays. However, their complications, infection and dysfunction, remain much too frequent. Different types of tunneled silicone hemodialysis catheters are available. We prospectively compared the long-term outcome of the two most popular devices, Permcath cuffed double catheter and TwinCath uncuffed twin catheter, both inserted percutaneously. METHODS: From January 1994 to April 1998, 125 tunneled catheters were inserted in the internal jugular vein of 86 chronic hemodialysis patients, 63 TwinCath MedComp (TC) and 62 Permcath Quinton (PC). They were prospectively followed looking for technical patency, infection and dysfunction rate. RESULTS: TC were used more often for iterative access (52 vs. 25%, p = 0.01) and were inserted more frequently in the left internal jugular vein (59 vs. 16% p < 0.001). Their median technical survival rate was longer (869 vs. 433 days for PC, p < 0.01) with a 1-year patency rate of 80 vs. 53% (p = 0.002). Total catheter extrusion was also slightly less frequent with TC (4.7 vs. 9.6%), but partial extrusion happened more frequently (43 vs. 16%, p = 0.02). No significant difference in infection rate was observed, 0.77 for TC vs. 1.3 local infection/1,000 catheter days; 1.08 vs. 1.30 bacteremia/1,000 catheter days. A persistent catheter thrombosis was observed in 7.9 vs. 20.9% in PC (p = 0.04), the number of dysfunction was 10.5 vs. 24/1,000 days in use (p = 0.0001) and the number of urokinase infusion was 4.4 vs. 12/1,000 days (p = 0.001). PC needed more radiological interventions for dysfunction with endolumenal brushes (4 vs. 0) or fibrin sleeve removal (4 vs. 0). The vena cava thrombosis incidence was not different (2 vs. 3). CONCLUSION: Although the study was not randomized, TC appears more efficient allowing for a longer patency with a lower dysfunction rate than PC. This was reinforced by less favorable conditions of TC including more left jugular side and more iterative catheters. The cuff does not offer a better bacteriological barrier or protection against extrusion, and the TC seems at a less risk of fibrin sleeves. However, a large randomized study is needed to definitively conclude.

Adult↗
PubMed2001

[Prevalence of stenosis and thrombosis of central veins in hemodialysis after a tunneled jugular catheter].

Central venous stenosis (ST) and thrombosis (TB) related to catheter (KT) had been reported mostly for the subclavian vein. We performed a systematic cavographic study to evaluate the prevalence of these complications in 51 hemodialysis patients with present or previous history of tunneled internal jugular catheter. Each of them had used one or several KT (1.8 +/- 1.4 KT) for a mean 28 +/- 26 month cumulative time (i.e. 43,584 days total exposure time). Fifty percent of the KT were PermCath Quinton and 50% were Twincath (uncuffed) or CS 100 (cuffed) Medcomp. Twenty-seven had no ST (53%, group I), 24 had one or several significant ST (47%, group II) of superior Vena Cava (SVC, n = 4), inferior Vena Cava (IVC, n = 1), Brachio-cephalic Vein (BCV, n = 5) and subclavian vein (SC, n = 10), or a TB of SVC (n = 1), IVC (n = 3), BCV (n = 3), SC (n = 2). This accounts for an incidence of 0.55 ST or TB/1000 patient-days. Five of the twelve subclavian ST and TB had no history of previous subclavian catheter. Comparison between the two groups showed no differences according to age, time on dialysis, diabetes, hematocrit, CRP, cumulative time with catheter, catheter-related infections, type of catheter and anticoagulant treatment. IVC catheter tip's position is an important risk factor for TB and ST (4/6). Twelve group II patients had ST or TB-related symptoms, with a functional AV fistula in 9 cases. Eleven patients underwent repeated percutaneous angioplasty with 4 additional Wallstents and in 2 cases an AV fistula need to be closed. Central venous ST and TB after a jugular KT is extremely frequent, mostly without any symptoms. Consequences on peripheral or central vascular access, cost and poor long-term patency rate of angioplasty are of major importance. These results incite us to further reduce the catheter use in dialysis patients.

Aged↗
PubMed1999

In search of ideal hemodialysis: is prolonged frequent dialysis the answer?

Advances in technology have made it possible to deliver a high Kt/V in a shorter time. The realization that duration of dialysis may be an important predictor of survival independent of dialysis dose has resulted in the popularity of prolonged slow dialysis (PHD). The longer duration and increased frequency of dialysis achieve excellent small- and middle-molecular weight solute clearance and also attenuate the peak concentration of uremic toxins. The slow dialysis process enables the equilibration of tissue and vascular compartments, resulting in better clearance and decreased postdialysis rebound increase in solutes. Gentle, persistent ultrafiltration allows the control of hypertension with minimal antihypertensive use. The intense and more frequent dialysis improves appetite and permits liberalization of diet. This greater dietary protein intake results in a progressive increase in serum albumin level and dry weight. Nocturnal hemodialysis achieves control of hyperphosphatemia without phosphate binders and a significant reduction in serum beta(2)-microglobulin levels. Normalization of extracellular volume, better clearance of uremic toxins, and improved nutrition result in a significant improvement in survival. The flexible time schedule with home hemodialysis and improvement of sleep and neurocognitive function allow better rehabilitation. The available evidence indicates PHD may be closer to the concept of an ideal dialysis, but there is lingering uncertainty about the consequence of prolonged immune stimulation, catabolism, and loss of essential solutes with these therapies.

Blood Urea Nitrogen↗
PubMed1999

Quest for postdialysis urea rebound-equilibrated Kt/V with only intradialytic urea samples.

BACKGROUND: Postdialysis urea rebound (PDUR) is a cause of Kt/V overestimation when it is calculated from predialysis and the immediate postdialysis blood urea collections. Measuring PDUR requires a 30- or 60-minute postdialysis sampling, which is inconvenient. Several methods had been devised for a reasonable approach to determine PDUR-equilibrated Kt/V in short dialysis without the need for a delayed sample. The aim of our study was to compare these different Kt/V methods during the longer eight-hour hemodialysis sessions, and to determine the optimum intradialytic urea sample time that fits best with PDUR. METHODS: The study included 21 patients (mean age 71.9 years) who were hemodialyzed for 60+/-60 months at three times eight hours weekly, using bicarbonate dialysate and cellulosic membranes. Blood urea samples were obtained at onset, and then at 17, 33, 50, 66, 75, 80, 85, and 100% of the dialysis session times, after 30 seconds of low flow, and then at 60-minutes postdialysis. All patients had a meal during dialysis. We compared four different formulas of Kt/V [(a) Kt/V-Smye with a 33% dialysis time urea sample, (b) two-pool equilibrated eKt/V, (c) Kt/V-std (Daugirdas-2) obtained with an immediate postdialytic sample, and (d) the different intradialytic urea samples for Kt/V (50, 66, 75, 80, and 85% of dialysis time)] with the equilibrated 60-minute PDUR Kt/V (Kt/V-r-60) formula as the reference method. RESULTS: The mean PDUR was 17.2+/-9%, leading to an overestimation of Kt/V-std by 12.2%. Kt/V-r-60 was 1.68+/-0.34. Kt/V-std was 1.88+/-0.36 (Delta = 12.2+/-4.8%, r = 0.8). eKt/V was 1.77+/-0.3 (Delta = 5+/-5%, r = 0.96), and Kt/V-Smye was 1.79+/-0.47 (Delta = 5.2+/-14%, r = 0.9). The best time for the intradialytic sampling was 80% (that is, at 6 hr and 24 min). The Kt/V-80 was 1.64+/-0.3 and was best fitted with Kt/V-r-60 (Delta = -1.8+/-8%, r = 0.91). The mean intradialytic urea evolution showed a three-exponential rate, in discrepancy with the two-exponential rate theoretical model. CONCLUSIONS: These results confirm that a significant postdialysis rebound exists in an eight-hour dialysis. An intradialytic urea sample taken at 80% of the total session time permits an estimation of the 60-minute Kt/V-rebound without the necessity of taking a delayed sample, with better accuracy than eKt/V or especially Kt/V-Smye. This may be related to a particular urea kinetics curve on the longer dialysis duration, which needs to be studied further.

Aged↗
PubMed1999

The Janus-faced aspect of 'dry weight'.

BACKGROUND: The goal of haemodialysis treatment in end-stage renal disease (ESRD) patients is to correct the complications of the uraemic condition. Among the main complications are fluid overload and subsequent hypertension that are corrected by achievement of 'dry weight'. We report in this study the evolution of post-dialysis body-weight and blood pressure in patients who began their HD treatment in our unit. METHODS: We studied the monthly evolution of post-dialysis body-weight (expressed as a percentage of pre-dialysis body-weight at the first HD treatment) and predialysis mean arterial pressure (MAP) over 24 months in 61 patients (21 females, mean age 59.8 years; 20% diabetic), treated with cellulosic membranes for 8 h, 3 times a week. RESULTS: The post-dialysis body-weight decreased between the onset of HD and month 2 (M2) (-4.40+/-0.52%). Then it went up, reaching -1.56+/-0.96% at M6, +0.3+/-1.27% at M12, +1.27+/-1.38% at M18 and +1.64+/-1.33% at M24. The post-dialysis body-weight increased by 6% between M2 and M24. The mean arterial pressure (MAP) decreased from 111.3+/-2.5 mmHg at M0 to 94.4+/-1.7 at M6, and then remained stable after M6. Between M2 and M6 the post-dialysis body-weight increased, whereas the predialysis MAP continued to decline. The incidence of hypotension episodes was maximal during the first 4 months of HD treatment. CONCLUSIONS: After the second month of dialysis treatment, the simultaneous increase of post-dialysis body-weight and decrease of pre-dialysis MAP are related to the effects of two processes, i.e. increased weight as the result of anabolism induced by the HD treatment on the one hand and normalization of blood pressure by fluid removal on the other. Continuous clinical assessment of the patient is necessary to provide adequate prescription of post-dialysis body-weight. During the first months of HD treatment, the nephrologist, like Janus, is a double-faced gatekeeper: he must be willing to decrease post-dialysis weight to achieve 'dry weight' and to normalize blood pressure, but he must also be prepared to increase it to compensate for anabolism and to avoid episodes of hypotension.

Analysis of Variance↗
PubMed1999

Fluid state and blood pressure control in patients treated with long and short haemodialysis.

BACKGROUND: Patients treated at the haemodialysis (HD) centre in Tassin, France have been reported to have superior survival and blood pressure (BP) control. This control has been ascribed to maintenance of an adequate fluid state, antihypertensive drugs being required in < 5% of the patients, although it could not be excluded that a high dose of HD regarding removal of uraemic toxins might also have been of value. METHODS: The aim of the study was to assess the fluid state and BP in normotensive patients on long HD (8 h) in Tassin (group TN) using bioimpedance to measure extracellular volume (ECV), ultrasound for determining the inferior vena cava diameter (IVCD), and 'on-line' monitoring of the change in blood volume (BV), and to compare them with normotensive (group SN) and hypertensive (group SH) patients on short HD (3-5 h) at centres in Sweden. ECV was normalized (ECVn) by arbitrarily setting the median ECV (in % of body weight) in SN patients at 100% for each gender, recalculating the individual values and combining the results for male and female patients in each group. RESULTS: The dose of HD (Kt/V urea) was higher for TN patients than for Swedish patients who had a similar Kt/V, whether hypertensive or not. SH patients had significantly higher ECVn and IVCD than TN and SN patients. TN and SN patients did not differ significantly regarding ECVn and IVCD before and after HD. However, in a subgroup of eight TN patients, ECVn was below the range of that in SH and SN patients, due to obesity with a high body mass index. Another subgroup of 14 TN patients had a higher ECVn than most of the SN patients and also higher than the median ECVn in the SH group, without any difference in body mass index, but they were nevertheless normotensive. The fall in BV was greater in SN than in TN patients, presumably due to a higher ultrafiltration rate in SN patients. However, SH patients had a smaller change in BV than SN patients, presumably because their state of overhydration facilitated refilling of BV from the interstitial fluid. CONCLUSIONS: Normotension can be achieved independently of the duration and dose (Kt/V urea) of HD, if the control of post-dialysis ECV is adequate. However, this is more difficult to achieve with short than with more prolonged HD during which the ultrafiltration rate is lower, BV changes are smaller and intradialysis symptoms less frequent. The results in the subgroup of patients with high ECVn at Tassin suggest that normotension may also be achieved in patients with fluid overload provided that the dialysis time is long enough to ensure more efficient removal of one or more vasoactive factors that cause or contribute to hypertension.

Adult↗
PubMed1999

The effect of long, slow haemodialysis on patient survival.

BACKGROUND: Long, slow haemodialysis (24 h/week) has been associated with excellent patient survival and reduced cardiovascular mortality. Comparisons of patient survival have only been possible with registry data and other published series which do not control for individual patient characteristics. This retrospective study compares actuarial patient survival between a unit using long, slow haemodialysis (Tassin) and one employing 'conventional' haemodialysis (Nottingham). METHODS: All patients undergoing haemodialysis at each centre since 1980 were included (Tassin, 452 patients; Nottingham, 282 patients). Actuarial curves of patient survival were calculated by the life-table method and log rank test was used to compare data. Patients were grouped as follows: standard (SRD) and non-standard (NSRD) renal diseases; diabetics and non-diabetics; patients with and without cardiovascular antecedents; risk stratification based on age and comorbidity. RESULTS: Overall survival was significantly better in Tassin. This difference was also noted for patients with SRD and non-diabetics (both P < 0.001) and for those with (P = 0.007) and without (P < 0.001) cardiovascular antecedents. Survival did not differ significantly for NSRD and diabetics. Survival was better in Tassin in low-risk (P < 0.001) and medium-risk (P < 0.001) groups, but not for high-risk (risk stratification). CONCLUSIONS: Overall survival is increased on long, slow haemodialysis. Although the benefits are seen in the most favourable prognostic categories, they are also present in patients with comorbid illness (medium-risk group) and pre-existing cardiovascular disease.

Adolescent↗