Micro-Channel Haemo Dialyser

2008 ◽  
Author(s):  
Goran N. Jovanovic ◽  
Eric K. Anderson ◽  
Alana R. Warner-Tuhy
Keyword(s):  
Flow Rate ◽  
Hollow Fiber ◽  
Mass Transfer Rate ◽  
Healthcare Providers ◽  
Blood Flow Rate ◽  
Expected Improvement ◽  
Renal Diseases ◽  
Health Lifestyle ◽  
Fiber Technology ◽  
Nocturnal Dialysis

The hollow fiber based haemo dialyzer made and extremely important impact in haemo dialysis practice in the last three decades. Many people with renal diseases were able to improve their life expectancy and maintain a somewhat improved health-lifestyle. With the prospect of doubling the number of renal patients in Europe and North America by 2020, and expected improvement of health care in developing nations current dialysis treatment models and practices need new approaches and above all new technical solutions. It appears that the hollow fiber technology has met technical limitations in further development of dialysis practices. The most obvious limitations are: i) high flow rate of dialysate with respect to blood flow rate and associated cost of dialysate, ii) inability to scale down the size of the hollow fiber dialyzer for pediatric use, or everyday nocturnal dialysis in adults without dramatic reduction of dialyzer efficiency, and iii) inability to increase the overall mass transfer rate and thus reduce the cost of both dialyzer and dialysate used. Microchannel haemo dialyzers with flat membranes, developed at Oregon State University, holds many promises that are pertinent to the needs of renal patients and healthcare providers.

Insensible water loss from the Jostra Quadrox D oxygenator: an in vitro study

Perfusion ◽  
2007 ◽  
Vol 22 (6) ◽  
pp. 407-410 ◽  
Author(s):  
DS Lawson ◽  
D Holt
Keyword(s):  
Flow Rate ◽  
Hollow Fiber ◽  
Water Loss ◽  
The United States ◽  
Electrolyte Balance ◽  
Primary Concern ◽  
Evaporative Water ◽  
Federal Drug Administration ◽  
Pump Flow Rate ◽  
Fiber Technology

Extracorporeal membrane oxygenation (ECMO) has been shown to improve outcomes in neonatal patients with respiratory and/or cardiac failure. Insensible water loss is defined as water loss via evaporation from the skin and respiration. Fluid and electrolyte balance are a primary concern and very challenging in the neonatal patient population. Hypernatremia can result from untreated insensible water loss, leading to possible cerebral complications. A new type of fiber used in the Jostra Quadrox D oxygenator has recently been approved for use in the United States of America. This oxygenator uses a polymethylpentene closed hollow-fiber technology and has been approved for six hours of continuous use by the Federal Drug Administration. The closed hollow-fiber technology may be advantageous for extended use due to the fact that it is a true membrane and plasma leakage will not occur across its surface. The Jostra Quadrox D is an adult-sized oxygenator with a surface area of 1.8 M2. The aim of this study is to discover what the insensible water loss will be from the Jostra Quadrox D when used at blood flows which would mimic those used for a neonatal ECMO patient. The median insensible water loss from the Quadrox D oxygenator at a gas flow rate of two liters per minute(LPM) was 4.0 ± 0.2 ml/hour, at five LPM was 9.8 ± 0.4 ml/hour and at 10 LPM was 20.6 ± 0.7 ml/hour. The daily evaporative water loss from the Jostra Quadrox D can be estimated to be 48.0 ± 2.1 ml for each LPM of sweep gas with a normal saline pump flow rate of 500 ml/min.

Effects of upper limb exercise programs on the arteriovenous fistula in patients on hemodialysis: A systematic review and meta-analysis

2021 ◽  
pp. 112972982110011
Author(s):  
Francini Porcher Andrade ◽  
Heloíse Benvenutti ◽  
Kacylen Costa da Silva ◽  
Paula Maria Eidt Rovedder
Keyword(s):  
Systematic Review ◽  
Arteriovenous Fistula ◽  
Flow Rate ◽  
Upper Limb ◽  
Handgrip Strength ◽  
Meta Analysis ◽  
Blood Flow Rate ◽  
Exercise Programs ◽  
Exercise Interventions ◽  
Limb Exercise

Background: The arteriovenous fistula (AVF) is a commonly used vascular access for chronic kidney disease (CKD) patients; exercise interventions may boost its maturation and help in its maintenance. A systematic review and meta-analysis of clinical trials on the effects of upper limb exercise programs on the AVF was conducted. Methods: The primary outcomes were draining vein diameter (DVD) and draining vein blood flow rate (DVBFR), and secondary outcomes were handgrip strength (HGS) and brachial artery flow rate (BAFR). Quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Results: Four studies met the inclusion criteria. When compared to usual care groups, the experimental groups did not improve DVD (mean difference [MD] 0.23, confidence interval [CI] −0.20–0.65). There were significant differences in DVBFR (mL/min) according to the fixed-effect model (MD 141.13, CI 36.84–245.42). HGS (kg) was significantly different between groups (MD 2.95, CI 0.55–5.35), but BAFR (mL/min) was not (MD 91.65, CI −94.72–278.01). Conclusions: Although exercise programs did not improve DVD and BAFR, they increased muscle strength and DVBFR. Therefore, experimental exercise programs should be emphasized for AVF maturation and maintenance. Research Registry number: reviewregistry924.

Scaling laws of vascular trees: of form and function

2006 ◽  
Vol 290 (2) ◽  
pp. H894-H903 ◽  
Author(s):  
Ghassan S. Kassab
Keyword(s):  
Flow Rate ◽  
Scaling Laws ◽  
Minimum Energy ◽  
Blood Flow Rate ◽  
Tree Structure ◽  
Conservation Of Energy ◽  
Form And Function ◽  
And Function ◽  
The Cost ◽  
Vascular Trees

The branching pattern and vascular geometry of biological tree structure are complex. Here we show that the design of all vascular trees for which there exist morphometric data in the literature (e.g., coronary, pulmonary; vessels of various skeletal muscles, mesentery, omentum, and conjunctiva) obeys a set of scaling laws that are based on the hypothesis that the cost of construction of the tree structure and operation of fluid conduction is minimized. The laws consist of scaling relationships between 1) length and vascular volume of the tree, 2) lumen diameter and blood flow rate in each branch, and 3) diameter and length of vessel branches. The exponent of the diameter-flow rate relation is not necessarily equal to 3.0 as required by Murray's law but depends on the ratio of metabolic to viscous power dissipation of the tree of interest. The major significance of the present analysis is to show that the design of various vascular trees of different organs and species can be deduced on the basis of the minimum energy hypothesis and conservation of energy under steady-state conditions. The present study reveals the similarity of nature's scaling laws that dictate the design of various vascular trees and the underlying physical and physiological principles.

The Effect of Furosemide on the Intrarenal Blood Flow Distribution in the Dog

1972 ◽  
Vol 50 (8) ◽  
pp. 774-783 ◽  
Author(s):  
Serge Carrière ◽  
Michel Desrosiers ◽  
Jacques Friborg ◽  
Michèle Gagnan Brunette
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Urine Volume ◽  
Flow Distribution ◽  
Blood Flow Rate ◽  
Initial Distribution ◽  
Blood Flow Distribution ◽  
Intrarenal Blood Flow ◽  
Femoral Blood ◽  
Furosemide Administration

Furosemide (40 μg/min) was perfused directly into the renal artery of dogs in whom the femoral blood pressure was reduced (80 mm Hg) by aortic clamping above the renal arteries. This maneuver, which does not influence the intrarenal blood flow distribution, produced significant decreases of the urine volume, natriuresis, Ccreat, and CPAH, and prevented the marked diuresis normally produced by furosemide. Therefore the chances that systemic physiological changes occurred, secondary to large fluid movements, were minimized. In those conditions, however, furosemide produced a significant increase of the urine output and sodium excretion in the experimental kidney whereas Ccreat and CPAH were not affected. The outer cortical blood flow rate (ml/100 g-min) was modified neither by aortic constriction (562 ± 68 versus 569 ± 83) nor by the subsequent administration of furosemide (424 ± 70). The blood flow rate of the outer medulla in these three conditions remained unchanged (147 ± 52 versus 171 ± 44 versus 159 ± 54). The initial distribution of the radioactivity in each compartment remained comparable in the three conditions. In parallel with the results from the krypton-85 disappearance curves, the autoradiograms, silicone rubber casts, and EPAH did not suggest any change in the renal blood flow distribution secondary to furosemide administration.

scholarly journals Preparation and characterization of different geometrical shapes of multi-bore hollow fiber membranes and application in vacuum membrane distillation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Elham M. El-Zanati ◽  
Eman Farg ◽  
Esraa Taha ◽  
Ayman El-Guindi ◽  
Heba Abdallah
Keyword(s):  
Mechanical Properties ◽  
Flow Rate ◽  
Hollow Fiber ◽  
Amorphous Structure ◽  
Membrane Distillation ◽  
Operating Conditions ◽  
Hollow Fiber Membranes ◽  
Preparation Conditions ◽  
Geometrical Shapes ◽  
Fiber Membranes

Abstract Multi-bore hollow fiber membranes were prepared through phase inversion spinning process using new locally designed spinnerets of various geometrical shapes. The spun cylindrical-like, rectangular or ribbon-like, and triangular-like are prepared, dried, and characterized by scanning electronic microscope. Fibers of circular (seven, five, and four bores) shape, rectangular of five bores, and triangular of three bores were chosen to study the effect of both geometrical configuration and the number of bores on the amorphous structure and the mechanical properties of the membranes. Membrane geometry, surface amorphous, and bore arrangements are very sensitive to the operating conditions, especially the extrusion and drawing rates. Three polymeric blends of different compositions are used to prepare multi-bore hollow fiber membranes. This study revealed that the blend composition of PES 16%, PVP 2%, PEG 2%, diethylene glycol 2%, and NMP 78% gives excellent mechanical properties. Optimization of the preparation conditions also developed, where the dope flow rate, the bore flow rate, and the air gap were 1.14 cm3 s−1, 1.1 cm3 s−1, and 0 cm, respectively. Furthermore, this study proved that the circular arrangement has high mechanical strength. The prepared seven-MBHF membranes were applied in the membrane distillation process, a solution of 35 g/l NaCl was used to test the membrane performance, and the achieved flux and rejection were 28.32 L/m2 h and 98.9%, respectively. This performance demonstrated that the prepared membrane in this way is suitable to compete with conventional reverse osmosis technology that uses single track hollow fibers.

Hollow Fiber Microfiltration and Ultrafiltration Products for High Purity Water Treatment Applications

2001 ◽  
Author(s):  
Randal M. Wenthold
Keyword(s):  
Water Treatment ◽  
Medical Device ◽  
Hollow Fiber ◽  
High Purity ◽  
Large Scale ◽  
Flat Sheet ◽  
Fiber Technology ◽  
Flat Sheet Membrane ◽  
Sheet Membrane ◽  
Filtration Device

Abstract For years in the semiconductor inductor industry the only choice individuals had for microfiltration or ultrafiltration devices consisted of flat sheet membrane manufactured into spiral wound or pleated filtration products. Polysulfone hollow fiber technology has evolved in the medical device industry for use as the highest purity type filtration device available. This unique technology is now available for use in the semiconductor business segment as well with product offerings that may be used in laboratory to large-scale applications.

The Effect of Hematocrit on the Clearance of Small Molecules during Hemodialysis

1983 ◽  
Vol 6 (3) ◽  
pp. 127-130 ◽  
Author(s):  
C. Woffindin ◽  
N.A. Hoenich ◽  
D.N.S. Kerr
Keyword(s):  
Blood Flow ◽  
Regression Analysis ◽  
Small Molecules ◽  
Flat Plate ◽  
Flow Rate ◽  
Distribution Curve ◽  
Blood Flow Rate ◽  
Hollow Fibre ◽  
Urea Clearance ◽  
Flow Rates

Data collected during the evaluation of a series of hemodialysers were analysed to see the effect of hematocrit on the clearance of urea and creatinine. All evaluations were performed on patients with a range of hematocrits with a mean close to 20%. The urea clearance of those in the upper half of the distribution curve (mean hematocrit 29.4%) was not significantly different from that of patients in the lower half of the distribution curve (mean hematocrit 16.9%) whether the clearance was studied at high or low blood flow rates and with hollow fibre or flat plate disposable hemodialysers. Likewise, there was no correlation between hematocrit and urea clearance by regression analysis. In contrast, the clearance of creatinine was affected by hematocrit being greater at lower hematocrit values. This difference was independent of blood flow rate and dialyser type and was confirmed by regression analysis.

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