Localised impedance monitoring device for the remote clinical assessment of home-based dialysis patients.

BioImpedance Spectroscopy (BIS) has been clinically used to determine the hydrational status of patients undergoing haemodialysis (HD). In the present project we are developing a calf-localised, integrated impedimetric device to periodically and conveniently measure and transmit information on the hydrational status of home-based patients to a remote clinic. Surprisingly, we have found that simple postural changes before or during measurement lead to significant fluid shifts in the lower leg that are as important and as long lasting as the effects of haemodialysis. These must be taken into account if potentially hazardous errors are not to be made in assessing a patient's hydrational status.

Wearable impedance monitoring system for dialysis patients.

This paper describes the development and the validation of a prototype wearable miniaturized impedance monitoring system for remote monitoring in home-based dialysis patients. This device is intended to assess the hydration status of dialysis patients using calf impedance measurements. The system is based on the low-power AD8302 component. The impedance calibration procedure is described together with the Cole parameter estimation and the hydric volume estimation. Results are given on a test cell to validate the design and on preliminary calf measurements showing Cole parameter variations during hemodialysis.

[Focusing on peritoneal dialysis adequacy]. / Adéquation en dialyse péritonéale : mise au point.

The optimal method to assess the adequacy of peritoneal dialysis therapies is controversial. Today, the adequacy must not be considered as a number or a concept assessed only by two parameters (total KT/V urea and total solute clearance) but defined by many more items. In the absence of data, based on theoretical considerations, the reanalysis of the CANUSA study showed that renal kidney function, rather than peritoneal clearance, was associated with improved survival. Residual renal function is considered as a major predictor factor of cardiovascular mortality. Results of this reanalysis were supported by the adequacy data in ADEMEX, EAPOS and ANZDATA studies. Therefore, clinical assessment plays a major role in PD adequacy. The management of fluid balance, the regular monitoring of malnutrition, the control of mineral metabolism and particularly the glucose load, considered as the "corner-stone" of the system, are the main points to be considered in the adequacy of PD patients. The essential goal is to minimize glucose load by glucose-sparing strategies in order to reduce the neoangiogenesis of the peritoneal membrane.

Short daily hemodialysis rapidly improves nutritional status in hemodialysis patients.

BACKGROUND: Malnutrition is a common problem in maintenance hemodialysis patients and is associated with increased mortality and morbidity. Interventions such as oral or intravenous nutritional supplements have often failed to improve nutritional status. We studied the effect of a daily dialysis program on nutritional parameters. METHODS: Eight patients treated with standard hemodialysis (SHD) 4 to 5 hours three times per week were converted to daily hemodialysis (DHD) 2 to 2.5 hours six times per week. Serum albumin, prealbumin, and total cholesterol were evaluated every three months. Anthropometry and dietary evaluation were performed every six months. RESULTS: Serum albumin rose from 39.0 +/- 2.6 to 42.0 +/- 3.1 and 43.0 +/- 2.6 g/L, prealbumin from 0.36 +/- 0.04 to 0.41 +/- 0.05 and 0.42 +/- 0.1 g/L, total cholesterol from 1.7 +/- 0.4 to 1.9 +/- 0.4 and 1.8 +/-0.3 g/L at baseline and at 6 and 12 months, respectively, after switching patients to DHD. Daily protein intake increased from 1.29 +/- 0.20 g/kg/day to 1.48 +/- 0.60 and 1.90 +/- 0.70 (P < 0.05). These changes were accompanied by a dry body weight increase of 2.4 +/- 1.6 kg (P < 0.005) at month 6 and 4.2 +/- 2.8 kg at one year (P < 0.05). Lean body mass increased from 47.7 +/- 4.9 kg to 49.1 +/- 5.9 (P < 0.05) and 50.5 +/- 6.2 (P < 0.05). CONCLUSIONS: Daily hemodialysis appears to be a suitable method to improve nutritional status in maintenance dialysis patients.

Haemodialysis with the biocompatible high permeability AN-69 membrane does not alter plasma insulin-like growth factor-I and insulin-like growth factor binding protein-3.

BACKGROUND: Insulin-like growth factor-I (IGF-I) bioactivity has been reported to be decreased in maintenance haemodialysis patients and this may affect their nutritional status. Clearances of IGF-I and its binding proteins (IGFBPs) during haemodialysis sessions using a high permeability biocompatible membrane are unknown. METHODS: Five well nourished, non-diabetic adult patients were studied during one 4-h morning haemodialysis treatment using the high permeability biocompatible AN-69 dialyser. Blood was collected at the arterial and venous ports of the dialyser at 0, 1, 2 and 4 h of dialysis for haematocrit, plasma IGF-I, IGFBP-3 and insulin measurements. IGF-I, IGFBP-3 and insulin concentrations were adjusted for haemoconcentration before comparisons were made. RESULTS: At the beginning of the dialysis session, plasma IGF-I, IGFBP-3 and insulin levels were within the normal range (297 +/- 47 ng/ml (mean+/-SEM), 4.3 +/- 0.6 microg/ml and 11.8 +/- 3.4 microIU/ml, respectively). During the session, insulin tended to be cleared through the dialyser, whereas plasma IGF-I and IGFBP-3 values did not vary significantly. CONCLUSION: Dialysis with the high permeability AN69 membrane did not alter the main blood compounds of the IGF system in well nourished chronic haemodialysis patients, and it is unlikely that the malnutrition frequently observed in such patients would result from alterations of the IGF system during haemodialysis.

Short daily hemodialysis and nutritional status.

Daily hemodialysis improves clinical outcomes in dialysis patients. This study shows the results of 10 patients who underwent short daily hemodialysis (SDHD) from 23.2 +/- 13 months and focuses on nutritional status under this strategy. With SDHD, patients had an increase in energy and protein intake confirmed by an increase in dry weight and lean body mass. Additional clinical improvement was obtained for blood pressure control, regression of left ventricular hypertrophy, correction of anemia, and better quality of life. These biological and clinical improvements are mainly the results of a higher frequency of dialysis sessions. The nutritional improvements with disappearance of anorexia are the consequence of general well being, less dietetic constraints, and less drugs prescribed. Short daily hemodialysis offers an adequate and more physiological strategy and may be considered for improving nutritional status in selected patients.

Twenty-five years of experience with out-center hemodialysis.

UNLABELLED: Twenty-five years of experience with out-center hemodialysis. BACKGROUND: Out-center hemodialysis (HD) offers patients a better quality of life, a greater independence, and a better rehabilitation opportunity. A lower mortality than with other modalities of dialysis has been reported. In addition, in France the charges paid depend on the modality of dialysis, out-center HD being the less expensive, and savings are also accomplished through fewer patient transports, which are additionally reimbursed. We present a 25-year experience of out-center HD. METHODS: We retrospectively studied the clinical records of 471 patients treated between 1974 and 1997 in a single nonprofit organization operating regional home HD (H-HD) and facilities for self-care HD (SC-HD). Survival results were analyzed according to: (a) causes of end-stage renal disease, (b) age at the start of HD, (c) period of start of HD, (d) modality of HD (H-HD, SC-HD), and (e) a subgroup of 174 patients defined at risk because they were contraindicated for transplantation. RESULTS: The mean age at the start of HD increased from 31.2 +/- 9.7 (mean +/- SD) years in 1974 to 52.6 +/- 13.5 years in 1997. Causes of the end of treatment were: (a) transplantation (63%), (b) transfer (20%), and (c) death (17%). The overall survival was 90% at 5 years, 77% at 10 years, 62% at 15 years, and 45% at 20 years, and, for the group at risk, 78%, 62%, 46%, and 31%, respectively. Cox proportional hazard analyses showed that risk factors were older age, diabetes, and renal vascular diseases. CONCLUSION: If adequate choice is given, out-center HD offers a reliable and safe modality of dialysis with better survival results than survival in full-care in-center HD. In addition, out-center HD ensures a striking financial benefit as compared with the higher costs if the same patients were treated with full-care in-center HD. These modalities should be encouraged for all HD patients who are able to be treated by out-center modalities.

Peritoneal clearance of leptin in continuous ambulatory peritoneal dialysis.

Leptin is a 16-kd protein that increases energy expenditure and limits food intake. Serum leptin (S-leptin) is elevated in dialysis patients, and little data have been reported on leptin clearance (Cl) during dialysis. We analyzed the peritoneal dialysis (PD) Cl of leptin in 15 continuous ambulatory peritoneal dialysis (CAPD) patients and compared the results to beta(2)-microglobulin (beta(2)-m), urea, and creatinine PD Cl. S-leptin was significantly elevated (Kruskal-Wallis, P < 0.005) in CAPD women (58.4 +/- 42.4 [SE] microg/L, n = 5) as compared with CAPD men (13.9 +/- 7.1, n = 10) and with healthy women (11.0 +/- 1.4, n = 13) and men (5.1 +/- 0. 9, n = 14). Correlations were found between percent of fat mass and S-leptin (P < 0.05); between S-leptin and the 24-hour PD leptin (P < 0.05); and between dialysate-to-plasma (D/P) beta(2)-m and D/P leptin (P < 0.01). PD leptin Cl (1.80 +/- 0.43 mL/min/1.73 m(2)) was higher than beta(2)-m Cl (1.22 +/- 0.31) (P < 0.01), but reduced as compared with urea Cl (8.84 +/- 1.20) (P < 0.005) and creatinine Cl (7.71 +/- 0.99) (P < 0.005). These results indicate that leptin is eliminated through the peritoneum membrane. However, peritoneal leptin clearance, as beta(2)-m, appears to be clearly restricted as compared with peritoneal transport of smaller molecules. Hence, leptin could use the same diffusion transport pathway as beta(2)-m. In addition, leptin, which has a higher molecular weight than beta(2)-m, was significantly more eliminated into the peritoneal dialysate. More studies are necessary to clarify whether this is an active leptin elimination process by peritoneal secretion or by a different restriction coefficient of diffusion through the peritoneum membrane.

Daily versus standard hemodialysis: one year experience.

The aim of this study was to compare clinical and biological results in 4 standard hemodialyzed patients originally treated by three 4-5 h sessions per week and converted within one year to daily hemodialysis sessions of 2-2.5 h each 6 times per week. The modalities and the total weekly dialysis times remained the same. With daily hemodialysis, the blood pressure and left ventricular mass index decreased significantly (p < 0.01). A significant decrease in the urea time averaged deviation (TAD) (p < 0.005) and increase in the Kt/V index (p < 0.05) were observed. A gain in dry weight was shown with a rise in caloric intake from 33+/-3.21 to 40.8+/-6.35 kcal/kg/day (p < 0.05), and the normalized protein catabolic rate (nPCR) increased significantly (p < 0.0038). One patient who was receiving erythropoietin (EPO) for anemia could stop his treatment. No arteriovenous fistula complications were observed. Daily hemodialysis seems to be the method of choice to manage hypertension and left ventricular hypertrophy in uremic patients. The increase of the urea TAD to a value closer to that of the healthy kidney due to the increase of the frequency of dialysis is probably the main explanation for clinical improvement.

Total body water and body composition in chronic peritoneal dialysis patients.

In this investigation, total body water (TBW) in ten chronic peritoneal dialysis patients was studied by deuterium (TBW-2H), skinfold thickness (TBW-ST), Watson formula (TBW-WA), 58% of body weight (TBW-58%), and bioelectrical impedance (TBW-BIA), and these results were compared with the reference oxygen18 (TBW-18O) method. We also analyzed the fat-free mass (FFM) by skinfold thickness (FFM-ST), bioelectrical impedance (FFM-BIA), oxygen18 (FFM-18O), and creatinine kinetics method (FFM-CK). In addition, resting metabolic rate was measured by indirect calorimetry. Compared with TBW-18O, TBW-58% and TBW-BIA were significantly different (P < 0.01). TBW-2H overestimated TBW-18O by 4.3%. TBW-ST and TBW-WA gave slightly greater values than TBW-18O, although these values were nonstatistically significant. The best prediction of total body water from these methods was obtained with the Watson formula. When Kt/V was calculated from these results, the values obtained were statistically greater (BIA, P < 0.001) and smaller (58% BW, P < 0.01) than those obtained with either 18O or Watson formula. The fat-free mass estimation also led to discrepant findings. Indeed, FFM-CK was significantly lower (P < 0.05) as compared with FFM-ST, FFM-BIA, or FFM-18O. Resting metabolic rate was strongly correlated with FFM estimated by skinfold thickness (r = 0.91, P < 0.001), bioelectrical impedance (r = 0.85, P < 0.005), and 18O (r = 0.77, P < 0.01), but not when fat-free mass was estimated by the creatinine kinetic method. The water content of fat-free mass estimated by skinfold thickness was found to be 69.7 +/- 6.9% in these patients, a value lower than the standard 73.2% found in healthy adults. This study confirms that there is an abnormal water distribution in chronic peritoneal dialysis patients. However, when compared with the oxygen18 reference method, the Watson formula allows a reliable estimation of Kt/V.

Quantification of adequacy of peritoneal dialysis.

Nineteen patients treated by continuous ambulatory peritoneal dialysis (CAPD) were studied according to clinical outcome parameters: insomnia, asthenia, pruritus, arterial hypertension, anorexia, nausea and/or vomiting, anemia, and rate of hospitalization. Using clinical scores, three groups were defined: poor clinical outcome (P), intermediate (I), and good (G). The quantity of treatment by PD was evaluated monthly with urea kinetic tests (weekly Kt/V, weekly urea clearance/1.73 m2 of body surface area (BSA), index of dialysis by Teehan), and with the weekly creatinine clearance/1.73 m2 of BSA. The metabolic index was analyzed: normalized protein catabolic rate (NPCR), serum albumin (Alb) and prealbumin, and reabsorption of glucose. There was good correlation between clinical scores and quantity of dialysis. The Alb was lower in group P. Group G was differentiated from group I and from group P by quantification tests and NPCR, with lower levels as follows: weekly Kt/V = 2.06, urea clearance 70 L/week/1.73 m2, index of dialysis = 0.87, and creatinine clearance = 60 L/week/1.73 m2. We conclude that the qualitative clinical approach is not sufficient to predict deleterious signs, and the quantitative approach is predictive of the good clinical outcome and good nutritional status. We think that levels proposed to now are insufficient, and we suggest the following: weekly urea clearance > 70 L, weekly Kt/V > 2, weekly creatinine clearance > 60 L, and index of dialysis > 0.85.

[Course of renal function in malignant hypertension. Effect of treatment. Study of 30 cases followed for 5 to 18 years]. / Evolution des fonctions rénales dans l'hypertension artérielle maligne. Influence du traitement. Etude sur 30 cas suivis de 5 à 18 ans.

Renal insufficiency is the most frequent complication of malignant hypertension (MHT). The initiation of effective hypotensive treatment is generally followed by a rapid improvement of renal functions, but the long-term evolution has been only rarely studied. A group of 30 patients was retrospectively selected on the following criteria: Malignant hypertension: mean DBP 138 +/- 20 mmHg, hypertensive retinopathy stage III-IV; Early renal insufficiency: mean Inulin clearance (CIN) 66 +/- 26 ml/min, mean PAH clearance (CPAH) 364 +/- 161 ml/min; Clinical and functional follow-up ranging from 5 to 18 years. Among these patients, two groups were defined according to the quality of BP control: good or fair responders (GR) with a DBP always less than 110 mmHg, poor responders (PR) with a DBP occasionally greater than or equal to 110 mmHg. The results show in the two groups an improvement of CIN at 3 years, followed by a stabilization then a decrease after the 6th year. However the early improvement is significantly lower in PR. Despite similar initial values (GR = 54.7 +/- 31.3; PR = 51.4 +/- 13.2), CIN remains always lower in PR (at 9 years = GR 72.4 +/- 30.6; PR 56.0 +/- 19.8). During the first 3 years, CPAH increases in GR, whereas it decreases in PR, resulting in significantly different values at 3 years. At 9 years, CPAH remains improved in GR (329.1 +/- 109.3 vs 281.7 +/- 173.8 initially) but decreased in PR (256.0 +/- 166.9 vs 307.3 +/- 119.5 initially). The parallel improvement of CIN and CPAH in GR confirms a favorable effect of BP control on early vascular lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute renal effects of beta-blockers.

The effects on renal function of a single dose of six different beta-blockers (atenolol, propranolol, metoprolol, acebutolol, nadolol, and pindolol) have been evaluated in 51 hypertensive patients with normal glomerular filtration rate (GFR). Most drugs, except pindolol, induce a 10-20% decrease in GFR and renal plasma flow, although differences in the magnitude and the pattern of this fall are evident. The fractional excretion of sodium is generally depressed by 20-40%. These data suggest a limited renal tolerance of most beta-blockers during acute administration, irrespective of their pharmacological characteristics.