It was the aim to measure the distribution volume and the elimination of ultra-pure dialysate in stable hemodialysis patients during on-line hemodiafiltration (HDF). Dialysate was automatically infused as a volume indicator using standard on-line HDF equipment. Indicator concentration was noninvasively measured in the arterial blood-line (using the blood volume monitor, Fresenius Medical Care, Bad Homburg vor der Höhe, Germany), and its time course was analyzed to obtain the elimination rate and the distribution volume V(t) at the time of dilution. Blood volume at treatment start (V0) was calculated accounting for the degree of intradialytic hemoconcentration. Five patients (two females) were studied during 15 treatments. Two to six measurements using indicator volumes ranging from 60 to 210 ml were done in each treatment. V0 was 4.59 ± 1.15 L and larger than the volume of 4.08 ± 0.48 L estimated from anthropometric relationships. The mean half-life of infused volume was 17.2 ± 29.7 min. Given predialysis volume expansion V0 was consistent with blood volume determined from anthropometric measurements. Information on blood volume could substantially improve volume management in hemodialysis patients and fluid therapy in intensive care patients undergoing extracorporeal blood treatment. The system has the potential for complete automation using proper control inputs for BVM and HDF modules of the dialysis machine.
Acute-on-chronic liver failure (ACLF) is accompanied by marked intrahepatic cholestasis leading to accumulation of cytotoxic bile acids. Extracorporeal liver support systems efficiently remove bile acids, but their effect on bile acid composition in ACLF is unknown. The aim of the present study was to compare elimination of individual plasma bile acids by albumin dialysis (Molecular Adsorbents Recirculating System, MARS) and fractionated plasma separation (Prometheus). Eight consecutive patients with ACLF underwent alternating 6-hour sessions with MARS or Prometheus in a randomized, cross-over design. Serum samples were obtained before, during, and after each treatment, and individual bile acids including cholic acid and chenodeoxycholic acid (CDCA) were measured by gas chromatography. MARS and Prometheus removed total bile acids to a similar extent (reduction ratio, 45% and 46%, respectively). Both devices cleared cholic acid more efficiently than did CDCA. The molar fraction of CDCA (fCDCA) was elevated at baseline and correlated with the degree of liver dysfunction. Prometheus but not MARS treatments further increased fCDCA. Although both devices eliminate total bile acids to a similar extent, clearance of individual bile acids is different, leading to a slight change of the bile acid profile toward hydrophobic bile acids during Prometheus treatments.
ORIGINAL ARTICLES♦ Background: Pre-dialysis education can guide the choice of the dialysis modality best tailored to meet the needs and preferences of individual patients with chronic kidney disease. ♦ Methods: In a retrospective single-center cohort study, we evaluated the impact of a pre-dialysis education program on the incidence rates of patients using hemodialysis (HD) and peritoneal dialysis (PD) in our unit. The frequency distribution of dialysis modalities between people attending our education program and people not attending the program (control group) was analyzed for the 4-year period 2004 -2008. ♦ Results: From among all the incident chronic kidney disease 5D patients presenting during the 4-year period, we analyzed 227 who started dialysis either with an arteriovenous fistula or a PD catheter. In that cohort, 70 patients (30.8%) took part in the education program, and 157 (69.2%) did not receive structured pre-dialysis counseling. In the group receiving education, 38 patients (54.3%) started with PD, and 32 (45.7%), with HD. In the standardcare group not receiving education, 44 patients (28%) started with PD, and 113 (72%), with HD (p < 0.001). ♦ Conclusions: Our multidisciplinary pre-dialysis program had a significant impact on the frequency distribution of dialysis modalities, increasing the proportion of patients initiating dialysis with PD.
Abstract-The aim of this study was to evaluate the effect of orthostasis on the time course of plasma adrenomedullin concentration. On 5 different days, normotensive subjects were randomized to undergo for 30 minutes either 12°, 30°, 53°, or 70°passive head-up tilt or to remain supine. Venous blood was collected from each subject in the supine position before tilting, at 3 and 27 minutes during tilting, and at 2 and 50 minutes after orthostasis. Plasma adrenomedullin increased significantly with tilt of Ն30°in a stimulus-dependent manner. Approximately half of the increase seen at 27 minutes occurred during the first 2 minutes of upright positioning; the maximum effect with 70°tilt was ϩ70%. Elevations in norepinephrine, epinephrine, aldosterone, plasma renin activity, vasopressin, heart rate, and mean arterial pressure were also significant. Hematocrit, blood density, plasma density, and plasma volume loss rose (PϽ0.05) at 53°a nd 70°tilt. Our results indicate that adrenomedullin may play an important role in stabilization of hemodynamics during passive orthostasis. In conclusion, plasma adrenomedullin rapidly increases with orthostatic challenge in a stimulus-dependent manner and also swiftly returns to baseline levels after the subject resumes the supine position. Key Words: tilt, head-up Ⅲ adrenomedullin Ⅲ barorereflex Ⅲ volume, plasma Ⅲ catecholamines T he 52-amino acid peptide adrenomedullin (ADM) is a potent vasorelaxant 1 and natriuretic 2 peptide. The strong relationship between plasma ADM and vascular tone functions in water homeostasis by increasing the glomerular filtration rate and natriuresis while lessening renal vascular resistance. 2,3 Additionally, ADM might function as an endothelium-derived relaxation factor and an autocrine or paracrine factor for vascular smooth muscle. 4 Until now, no data were available on changes in plasma ADM levels induced by orthostasis, which redistributes blood from central-to lower-body vascular beds and unloads cardiopulmonary receptors 5 ; this causes constriction of resistance and capacitance vessels, 6 in part through the action of vasopressin, angiotensin, and endothelin-1. 7,8 The present investigation was designed to test the hypothesis that plasma ADM is influenced by head-up tilting (HUT) in normotensive, euhydrated humans; to study the time course of ADM during and after HUT; and to quantify effects in relation to the intensity of orthostatic challenge. As ancillary information, hemodynamic and other endocrine as well as blood volume indicators were determined. The present study shows that ADM responds quickly and in a dose-dependent manner to HUT, and its concentration rapidly declines afterward.
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