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Biomedical subjects

B Canaud

Publications and source records attributed to B Canaud.

At least 109 records · Page 6Linked to original sources
PubMed1991

[Urea kinetic model analysis in dialysis: from theory to practice].

Urea kinetic modeling (UKM) has been originally proposed by F. Gotch and J. Sargent as a guide to optimize and individualize the dialysis prescription in uremic patients. In a recent report, the US National Cooperative Dialysis Study group, showed the power of this approach compared to conventional methods. It was also concluded that dialysis adequacy could be predicted with a high success rate by determining three parameters; uremia represented by the Urea Time Averaged Concentration, dialysis dose defined as KT/V ratio, and dietary protein intake calculated from the urea generation rate. In spite of its potential usefulness, UKM has not gained clinical acceptance among nephrologists since it appeared always complicated due to its mathematical formulation or cumbersome to be used routinely in dialyzed patients. In this paper the authors will bring the reader from basic concepts to practical use of UKM to guide dialysis strategy. Limits of validity and difficulty in using this approach are also discussed. It is concluded that UKM by using very simple and basic parameters is a practical, and very powerful tool for assessing the dialysis adequacy and nutritional status of dialyzed patients. Direct quantification from dialysate (or ultrafiltrate) collection appeared a simple and precise method which should avoided multiple blood sampling.

Humans↗
PubMed1990

[One-year treatment of 43 chronic hemodialysis patients with recombinant human erythropoietin].

Twenty men and 23 women aged from 18 to 65 years, who had been under maintenance haemodialysis for 2 to 16 years and whose haematocrit had been below 30 percent for at least 3 months received recombinant human erythropoietin intravenously at the end of each session for one year. Anaemia was corrected in all patients, the delay in response to each dosage variation being about 4 weeks. The necessary maintenance dosage ranged from 96 to 240 u/kg/week. The number of leucocytes increased significantly until the 4th month, from 5880 +/- 1760 to 6600 +/- 1920 per cubic mm (P less than 0.01). During treatment, pre-dialysis blood creatinine concentrations and potassium and phosphate levels rose, while blood calcium levels fell significantly from 2.45 +/- 0.16 to 2.36 +/- 0.19 mmol/l (P less than 0.01). A nonsignificant increase in systolic and diastolic pressures was also observed, from 129 +/- 16 to 134 +/- 18 mmHg (P = 0.06) and from 75 +/- 9 to 78 +/- 10 mmHg (P = 0.07) respectively. Eight patients (18 percent) required antihypertensive drugs or a higher dose of those previously prescribed. There were 7 cases of vascular thrombosis on pre-existing stenosis, and the dosage of heparin during dialysis had to be increased in most patients. This study confirms that erythropoietin plays a major role in the genesis of the anaemia associated with renal failure. The absence of severe complications in this series was probably due to the criteria of inclusion in the study.

Adolescent↗
PubMed1990

Recombinant human erythropoietin: 18 months' experience in hemodialysis patients.

It has been shown that the regular administration of erythropoietin (EPO) permits the correction of anemia in end-stage renal failure patients. We analyzed the effect of chronic administration of EPO in 13 stable, regularly dialyzed end-stage renal failure patients over an 18-month period. The effects of EPO were evaluated according to standard criteria including clinical status, blood pressure control, hematology and biochemistry data, protein nutritional status, and dialysis efficiency. Following a 2-week control period, EPO was administered intravenously (IV) after the dialysis session according to a two-phase protocol. The first period (correction phase) consisted of a stepwise EPO dose increment, starting at 3 x 24 IU/kg/wk and doubling the dose every 14 days according to hemoglobin response in order to achieve a target hemoglobin level of approximately 11.0 g/dL (110 g/L). In the second period (maintenance phase) EPO dose was optimized to maintain the hemoglobin level between 100 and 110 g/L (10.0 and 11.0 g/dL), by adjusting either the unit dose or the frequency of injection. Anemia was corrected in all patients within 11 weeks, with EPO dose increasing from 72 to 360 IU/kg/wk. The stabilization of hemoglobin was achieved with an average EPO dose of 275 IU/kg/wk (50 to 476 IU/kg/wk). Concomitantly, a subjective and clinical improvement was noted in all patients. The dialysis efficacy remained in an acceptable range throughout the study, falling significantly (approximately 10%) through the first 3 months of treatment to stabilize at an effective urea clearance of approximately 120 L/wk. The dietary protein intake calculated from urea kinetic modeling ranged between 1.1 and 1.2 g/kg/d.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

A study of beta 2-microglobulin skin deposits in dialyzed patients and healthy controls.

This study reports on beta 2-microglobulin (beta 2M) deposits in the skin of 12 uremic patients and three kidney transplant recipients compared with eight healthy controls. Uremic patients were treated by hemodialysis (HD), hemofiltration (HF), hemodiafiltration (HDF), or continuous ambulatory peritoneal dialysis (CAPD) for a period lasting from 1 to 19 years. Congo red staining of the skin was negative in patients and controls. However, immunofluorescent staining with an anti-beta 2-microglobulin monoclonal antibody was positive in the skin of all patients and of six of the eight controls. Beta 2M skin deposition is more intense in patients than in controls and increases with patient age and the duration of dialysis. A stron correlation is observed between the extent of skin beta 2M deposits and clinical manifestations due to beta 2M deposits in internal organs. However, no correlation is found between beta 2M skin deposits and sex or beta 2M serum levels.

Adult↗
PubMed1990

[Amyloid arthropathy of the hand in patients on chronic hemodialysis].

Among 70 patients treated by hemodialysis for renal failure and operated for carpal tunnel syndromes, 17 presented with bone and joint lesions. Seven of them had destructive arthropathies of the distal interphalangeal joint, bilateral in 6 cases. Two radiological stages are described. Radiolucent lesions of the carpal bones were present in all the patients ("carpal amyloidosis"). The most frequent sites were around the radius-scaphoid-lunate and scaphoid-lunate joint spaces. Scaphoid-trapezoid-trapezium arthropathy was frequent with dynamic instability in one case. One patient had a pathological fracture of the lunate and scaphoid. Carpal tunnel syndrome was associated in all cases and dorsal wrist tenosynovitis in three cases. Amyloid arthropathy is more frequent in old patients on long-term hemodialysis. Amyloid deposits were shown in tendinous and joint synovial biopsy. The pathogenesis of amyloidosis is discussed.

Aged↗
PubMed1990

Effect of reuse on dialyzer efficacy.

The effect of reuse on dialyzer efficacy was examined by measuring blood compartment volume and dialyzer mass transfer coefficient (maximum dialyzer clearance) as a function of dialyzer use number. The 102 polysulfone dialyzers tested (F60 and HF80, Fresenius) were reprocessed on Renatron machines using peroxyacetic acid as the dual cleansing and sterilizing agent. Each dialyzer was used an average of 14.4 +/- 5.7SD times and was tested once (twice for 13/102 dialyzers) during a routine dialysis session at an arbitrary use number (7.6 +/- 5.3; range 1 to 24). The parameters tested were found to decrease only marginally with reuse, corresponding to a blood compartment volume loss of approximately 1% (R = 0.04) over a 5-week/15-use period and a decrease in dialyzer mass transfer coefficient of approximately 3% (R = 0.07 and 0.06) over the same period for urea and creatinine, respectively. It was concluded that the loss in dialyzer efficacy is negligible over the average use period of almost 5 weeks per dialyzer.

Blood Volume↗
PubMed1990

Clinical and microbiological evaluation of a postdilutional hemofiltration system with in-line production of substitution fluid.

Safety and efficacy of a recently developed hemofiltration (HF) system with in-line production of substitution fluid (GHS-10; Gambro, Lund, Sweden) based on a sterilizing filtration of acetate buffered dialysate has been evaluated in 4 patients over a 6-month period. Two patients were prematurely excluded from the study: 1 because of acetate intolerance and the other because of kidney transplantation. Two patients completed the study (240 HF sessions). Treatment adequacy was maintained in the 2 medium term treated patients according to the usual clinical and biochemical criteria and a mean exchange volume of 100-105 liters/week (30-35 liters/session three times weekly). Urea kinetic modeling analysis performed over all HF cycles gave the following results: dialysis index (urea clearance.time-on HF/urea volume space) (KT/V) approximately 1-1.1, urea time averaged concentration (UREA TAC) approximately 15-20 mmol/l, and protein catabolic rate (PCR) approximately 1.1-1.2 g/kg/day. Rare clinical adverse symptoms observed during the course of sessions were attributed to acetate intolerance. Microbiological safety was confirmed in vivo by the absence of pyrogenic reactions after 240 HF sessions (approximately 7 m3 substitution fluid infused intravenously) and in vitro by the constant absence of bacteria and/or endotoxin content limulus amaebocyte lysate (LAL) sensibility threshold 10 pg/l within the infusate produced during the sham HF sessions. The fluid mass balance obtained with the GHS-10 monitor was excellent. The electrolyte composition as judged by Na variation remained in a range of 2-3%. GHS-10 used in this study for postdilutional HF confirms that a large quantity of intravenous quality fluid may be safely produced by ultrafiltration from dialysate. It also introduced a new dimension in biocompatibility of dialysis by demonstrating that sterile dialysate may be routinely produced and used for routine dialysis.

Adult↗
PubMed1990

Erythropoietin-induced changes in protein nutrition: quantitative assessment by urea kinetic modeling analysis.

To evaluate objectively the effects of recombinant human erythropoietin (rHuEPO) administration on nutritional status in stable dialyzed patients, we used urea kinetic modeling (UKM) analysis and dietary protein intake evaluation by dietary assessment. Fifteen patients (9 females, 6 males; mean age 46.9 +/- 15.6 years) dialyzed for 9.4 +/- 6.3 years were studied longitudinally for 18 months, consisting of a control period (6 months) and an rHuEPO treatment period (12 months). Treatment modalities based on 3 weekly sessions were hemodialysis in 12 patients (6 cuprophane, 3 cellulose acetate and 3 highly permeable membranes), hemodiafiltration in 2 patients and postdilutional hemofiltration in 1 patient. Bicarbonate buffered dialysate was used in 9 patients and acetate in 6 patients. Urea kinetic modeling using a single-pool model was performed monthly over 1-3 cycles. rHuEPO was administered intravenously at the end of dialysis according to a two-phase protocol: (1) correction of anemia by stepwise increment of rHuEPO dose, and (2) maintenance dose to keep hemoglobin at 10-11 g/dl. rHuEPO administration corrected anemia in all patients, improving their general clinical condition. Dialysis efficacy was significantly reduced (15%) after the 3rd month of rHuEPO therapy. Clearnces were restored by increasing dialysis time and/or improving dialyzer performances, and adequacy of dialysis was maintained in all patients. During the 12 months of rHuEPO therapy, the protein catabolic rate remained stable at 1.2 g/kg/24 h in spite of an increase in appetite. At the same time, dry body weight increased significantly after 9 months, and the ratio dietary protein intake/protein catabolic rate a gross estimation of nitrogen balance, increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Recombinant human erythropoietin: 18 months of continuous use in substitution hemodialysis].

It has been shown that the regular administration of EPO permits the correction of anemia in end stage renal failure patients. We analyzed the effect of chronic administration of EPO in 13 stable, regularly-dialysed end stage renal failure patients over an 18 month period. The effects of EPO were evaluated according to standard criteria including clinical status, blood pressure control, hematology and biochemistry data, protein nutritional status and dialysis efficiency. Following a 2 week control period, EPO was administered intravenously after the dialysis session according to a 2 phase protocol. The first period (correction phase) consisted of a stepwise EPO dose increment, starting at 24 IU/kg x 3 times and doubling the dose every 14 days according to hemoglobin response in order to achieve a target hemoglobin level of 11 g/dl. In the second period (maintenance phase) EPO dose was optimized to maintain the hemoglobin level between 10 and 11 g/dl, by adjusting either the dose or the frequency of injection. Anemia was corrected in all patients within 10 weeks with EPO dose increasing from 72 to 360 IU/kg/week. The stabilisation of hemoglobin was achieved with an average EPO dose of 275 IU/kg/week (50 to 476 IU/kg/week). Concomitantly, a subjective and clinical improvement was noted in all patients. The dialysis efficacy, although remaining in an acceptable range, fell significantly by 10% over the first 3 months of treatment, remaining stable afterwards, yielding an effective urea clearance near to 120 1/week. The dietary protein intake calculated from urea kinetic modelling ranged between 1.1 and 1.2 g/kg/day.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Germicidal effectiveness of Dialox, a new stable peroxyacetic acid solution, in the re-use of high-flux dialysers.

In this study we evaluate the effectiveness of a newly available peroxyacetic acid solution (Dialox) as a disinfecting agent in the re-use of highly permeable dialysers. The germicidal properties of Dialox were tested in an in vitro trial on previously used haemodiafilters (HF80, Fresenius) highly contaminated with Pseudomonas aeruginosa, Mycobacterium smegmatis or sporulated Bacillus cereus. Complete freedom from bacterial contamination was observed 5 min after the reprocessing treatment on a Renatron reprocessing machine, using the currently marketed Dialox concentrate.

Acetates↗
PubMed1989

Urea kinetic modelling by partial dialysate collection.

Conventional urea kinetic modelling (UKM) has several drawbacks, in particular the complexity of the required calculations and the need for accurate values of parameters which are difficult to measure, such as dialyzer clearance and blood flow. An alternative method of UKM is proposed based on collecting a small fraction of spent dialysate flow for 3 consecutive dialyses. Application of a urea mass balance to the 7 day period permits neglecting changes in body urea stores. Thus no blood sampling is required for most patients. The required calculations are simple and straightforward. The partial dialysate collection (PDC) method was compared to conventional UKM in a 3 patient, 15 week study. Protein catabolic rate (PCR) from PDC was a smooth curve and consistent with dietary estimation for each patient. Conventional UKM gave variable PCR results which were 17-27% higher on average. This discrepancy was attributed to overestimation of dialyzer clearance. PDC was concluded to be more convenient and accurate than conventional UKM and therefore ideal for routine clinical use.

Adult↗