Biological Sciences
Dialysis
Dialysis is a medical procedure used to remove waste products and excess fluids from the blood when the kidneys are unable to perform this function. It involves the use of a machine to filter the blood and return it to the body. Dialysis is commonly used to treat individuals with kidney failure and helps to maintain the body's overall balance of fluids and electrolytes.
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11 Key excerpts on "Dialysis"
eBook - ePubChronic Kidney Disease, Dialysis, and Transplantation E-Book
A Companion to Brenner and Rector's The Kidney
- Jonathan Himmelfarb, T. Alp Ikizler(Authors)
- 2018(Publication Date)
- Elsevier(Publisher)
Several methods to achieve this exist, including hemoDialysis, hemofiltration, and hemodiafiltration. The most successful intracorporeal modality has been peritoneal Dialysis. The most promising replacement therapy is kidney transplantation because it can restore normal or near-normal kidney function, including potential functions not yet discovered, with the least inconvenience to the patient. The kidney is also an endocrine organ involved in the metabolism of hormones such as erythropoietin, calcitriol, prostaglandins, and renin. Overall care of the patient requiring renal replacement therapy also requires anticipation and management of problems; current approaches include attempts to reverse the psychological effects of kidney loss, preventing anemia and bone disease, monitoring the patient for signs of protein-energy wasting, monitoring the function of peripheral AV access devices, expecting hypotension during Dialysis in patients with concentric ventricular hypertrophy, adjusting medication doses appropriately, and monitoring the quality of dialysate water (detailed in various chapters). Clinical practice guidelines and practical recommendations have been published and are now available in several countries, each with the ultimate goal of improving quality of life. 11 - 13 Definitions Dialysis is the passage of molecules in solution by diffusion across a semipermeable membrane. Essential elements of this process are the solvent, which contains dissolved solutes, and the membrane that contains pores through which some or all of the solutes move by diffusion (Fig. 22.1A). The molecular kinetics of diffusion are both solute and membrane specific. Solute characteristics that affect movement across a particular membrane include its concentration, molecular weight, shape, charge, and lipid solubility
- Elliott, Jonathan, Grauer, Gregory F., Westropp, Jodi, Elliott, Jonathan, Grauer, Gregory F., Westropp, Jodi(Authors)
- 2017(Publication Date)
- British Small Animal Veterinary Association(Publisher)
Chapter 22 254 BSAVA Manual of Canine and Feline Nephrology and Urology, third edition. Edited by Jonathan Elliott, Gregory F. Grauer and Jodi L. Westropp. ©BSAVA 2017 HaemoDialysis and peritoneal Dialysis Sheri Ross and Cathy Langston Principles of Dialysis Dialysis is a method of treating kidney failure and certain types of toxicities, and includes haemoDialysis (HD) and peritoneal Dialysis (PD). The principles are similar for HD and PD. However, during HD, the exchange of solutes and water between the patient’s blood and the prepared dialysate solution occurs extracorporeally, across a manu-factured membrane, whereas during PD this exchange occurs within the abdominal cavity using the peritoneum as the membrane. Methods of clearance Solute and fluid removal during Dialysis occurs via four different mechanisms: diffusion, ultrafiltration, convection and adsorption (Figure 22.1). The relative contribution of each of these mechanisms to the removal of solutes will depend upon the properties of the semipermeable mem-brane, the solute of interest and the relative pressures acting across the membrane. Diffusive transfer of solute relies on the random move-ment of particles through the pores of the dialyser membrane (or the peritoneum) from a solution of higher concentration to a solution of lower concentration. Once concentration equilibrium has been achieved between the two solutions, an equal bidirectional exchange continues, with no net change in the solute concentration on either side of the membrane. During HD, constant replenishment of fresh dialysate within the dialyser prevents equilibrium from being established, thus maintaining active diffusion. The efficiency of diffusion is further increased by using a countercurrent direction of flow between blood and dialysate that maximizes the concentration gradient. Molecular weight strongly influences the kinetic motion of a solute and this is inversely related to the rate of diffusion.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- The English Press(Publisher)
________________________ WORLD TECHNOLOGIES ________________________ Chapter 7 HemoDialysis HemoDialysis in progress ________________________ WORLD TECHNOLOGIES ________________________ HemoDialysis machine In medicine, hemoDialysis (also haemoDialysis ) is a method for removing waste products such as creatinine and urea, as well as free water from the blood when the kidneys are in renal failure. HemoDialysis is one of three renal replacement therapies (the other two being renal transplant; peritoneal Dialysis). HemoDialysis can be an outpatient or inpatient therapy. Routine hemoDialysis is conducted in a Dialysis outpatient facility, either a purpose built room in a hospital or a dedicated, stand alone clinic. Less frequently hemoDialysis is done at home. Dialysis treatments in a clinic are initiated and managed by specialized staff made up of nurses and technicians; Dialysis treatments at home can be self initiated and managed or done jointly with the assistance of a trained helper who is usually a family member. ________________________ WORLD TECHNOLOGIES ________________________ Principle Semipermeable membrane The principle of hemoDialysis is the same as other methods of Dialysis; it involves diffusion of solutes across a semipermeable membrane. HemoDialysis utilizes counter current flow, where the dialysate is flowing in the opposite direction to blood flow in the extracorporeal circuit. Counter-current flow maintains the concentration gradient across the membrane at a maximum and increases the efficiency of the Dialysis. Fluid removal (ultrafiltration) is achieved by altering the hydrostatic pressure of the dialysate compartment, causing free water and some dissolved solutes to move across the membrane along a created pressure gradient. The Dialysis solution that is used may be a sterilized solution of mineral ions or comply with Britich Pharmacopea. Urea and other waste products, potassium, and phosphate diffuse into the Dialysis solution.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- College Publishing House(Publisher)
________________________ WORLD TECHNOLOGIES ________________________ Chapter 7 HemoDialysis HemoDialysis machine ________________________ WORLD TECHNOLOGIES ________________________ HemoDialysis in progress In medicine, hemoDialysis (also haemoDialysis ) is a method for removing waste pro-ducts such as creatinine and urea, as well as free water from the blood when the kidneys are in renal failure. HemoDialysis is one of three renal replacement therapies (the other two being renal transplant; peritoneal Dialysis). HemoDialysis can be an outpatient or inpatient therapy. Routine hemoDialysis is con-ducted in a Dialysis outpatient facility, either a purpose built room in a hospital or a dedicated, stand alone clinic. Less frequently hemoDialysis is done at home. Dialysis treatments in a clinic are initiated and managed by specialized staff made up of nurses and technicians; Dialysis treatments at home can be self initiated and managed or done jointly with the assistance of a trained helper who is usually a family member. ________________________ WORLD TECHNOLOGIES ________________________ Principle Semipermeable membrane The principle of hemoDialysis is the same as other methods of Dialysis; it involves diff-usion of solutes across a semipermeable membrane. HemoDialysis utilizes counter current flow, where the dialysate is flowing in the opposite direction to blood flow in the extra-corporeal circuit. Counter-current flow maintains the concentration gradient across the membrane at a maximum and increases the efficiency of the Dialysis. Fluid removal (ultrafiltration) is achieved by altering the hydrostatic pressure of the dialysate compartment, causing free water and some dissolved solutes to move across the membrane along a created pressure gradient. The Dialysis solution that is used may be a sterilized solution of mineral ions or comply with Britich Pharmacopea. Urea and other waste products, potassium, and phosphate diffuse into the Dialysis solution.
eBook - PDFRenal Nursing
Care and Management of People with Kidney Disease
- Nicola Thomas, Helen Noble(Authors)
- 2024(Publication Date)
- Wiley-Blackwell(Publisher)
1 Renal Nursing: Care and Management of People with Kidney Disease, Sixth Edition. Edited by Nicola Thomas and Helen Noble. © 2024 John Wiley & Sons Ltd. Published 2024 by John Wiley & Sons Ltd. CHAPTER 1 INTRODUCTION The introduction of Dialysis as a life-saving treatment for end-stage kidney disease (ESKD) was not the result of any large-scale research programme; rather, it emerged from the activities of a few pioneering individuals who were able to use ideas, materials, and methods from a range of devel- oping technologies. HaemoDialysis (HD), as a routine treatment for ESKD, was initiated in the 1960s, followed by continuous ambulatory peritoneal Dialysis (CAPD) in the late 1970s. The recognition of the need for immunosuppression in transplantation in the 1960s enabled it to become the preferred treatment for many patients. HAEMODialysis THE BEGINNING It was the Romans who first used a form of Dialysis therapy by giving hot baths to patients to remove urea. The action of the hot water made the patient sweat profusely and this, together with the toxins diffusing through the skin into the bath water, would temporarily relieve symptoms. However, the Romans did not understand why the treatment worked. The effect was to leave the patient fatigued but, as the only hope, this treatment was still used on occasion into the 1950s. The first time that the term Dialysis was used was in 1854, by Thomas Graham, a Scottish chemist (Graham 1854). He used Dialysis to describe the transport of solutes through an ox bladder, and this was the catalyst for other researchers working in a similar field to focus on the membrane. Membranes were made from a variety of substances, including parchment and collodion (Eggerth 1921). Collo- dion is a syrupy liquid that dries to form a porous film and allows the passage of small-molecular-weight substances, whilst being impermeable to substances with a molecular weight greater than 5 kDa.
eBook - ePubKidney Transplantation, Bioengineering, and Regeneration
Kidney Transplantation in the Regenerative Medicine Era
- Giuseppe Orlando, Giuseppe Remuzzi, David F. Williams, Giuseppe Orlando, Giuseppe Remuzzi, David F. Williams(Authors)
- 2017(Publication Date)
- Academic Press(Publisher)
9 This process is leveraged further in HF, where pores in semi-permeable membranes allow water and solutes across the membrane independent of the concentration gradient, and predominantly on the hydraulic pressure gradient across the membrane, which mimics the filtration function of the nephron. HDF combines HD and HF processes, where both diffusion and hydraulic pressure are used as driving forces.83.2.1 Dialysis
Dialysis is a process of removing toxins and metabolic byproducts from patients’ circulating blood based on diffusion and, to a lesser extent, ultrafiltration across a semi-permeable membrane. Dialysis is currently carried out either by HD or PD. In HD, blood exits the body through a catheter, and heparinized silicone tubing delivers the blood to the dialyzer (Fig. 83.2A ). These dialyzers are commonly filled with hollow fiber membranes formed into a bundle. Within a hollow fiber dialyzer, blood flows through the lumen, the interior, of each hollow fiber. Solutes in the blood interact with the fiber’s semi-permeable membrane, which allows for low MW solutes such as urea and creatinine to pass through the fiber wall into the extracapillary space (ECS) of the dialyzer for removal, while blood cells and critical large proteins such as albumin and immunoglobulin are retained in the blood (Fig. 83.3 ). Dialysate, the fluid which flows opposite the blood on the other side of the semi-permeable membrane in the ECS, is an aqueous solution with various concentrations of solutes that dictate the driving force to remove, retain, or add to solute concentrations in the blood. Movement of the solute is directed from high concentration to low concentration so that toxins are removed, and critical electrolytes in the blood are maintained.Figure 83.2 Schematic representation of hemoDialysis (HD, (A)) and hemofiltration (HF, (B)), and various hemodiafiltration methods: Push-Pull (C), Double HDF (D) and Hemofiltrate Reinfusion (HFR, (E)).Figure 83.3 Separation methods: macrofiltration, microfiltration, ultrafiltration, and reverse osmosis, with molecules, pathogens and cells of interest to Dialysis technologies. Molecules of interest color-coded: red =toxins for removal: urea, endotoxin, microglobulin, myoglobulin, yellow =molecules removed by HD/HF to be balanced by clinicians: Na+ , Cl− , K+ , PO4 3− , glucose, insulin, Vit B12 , green
eBook - PDF- Hiromichi Suzuki(Author)
- 2015(Publication Date)
- IntechOpen(Publisher)
In this chapter, Dialysis membrane and its materials are extensively discussed from the physicochemical points of view, including microscopic views taken by scanning electron microscope (SEM), mathematical expressions of membrane transport, fundamental in vitro experiments as well as in vivo trials or clinical experiences. © 2015 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 2. Basic principles and history of Dialysis membrane 2.1. Law of diffusion Dialysis is a phenomenon at which two different fluids (usually liquids) are separating flowing on either side of the membrane (usually counter-currently) and the solute of interest in higher concentration transports across the membrane due to concentration gradient in accordance with the Fick’s 1-st law of diffusion, i.e., J A x = -D A x ∂ C A ∂ x (1) where x is the co-ordinate in the diffusion direction [m], J A x is the mass flux of solute A in x direction [kg/(s m 2 )], D A x is the diffusion coefficient of A in x direction [m 2 /s], and C A is the concentration of A [kg/m 3 ]. Dialysis, therefore, is one of separation techniques of the solute of interest by using the membrane and is applied elsewhere in many industrial as well as laboratory situations. Letting C A0 and C AL to be the concentrations of A at x =0 and x = L , respectively (Figure 1), Eq.(1) is integrated in a straight-forward manner to get, J A x = ( D A x L ) ( C A0 -C AL ) ≡ k M × ( C A0 -C AL ) (2) where k M is the membrane permeability [m/s] defined by ( D A x / L ). From Eq.(2), one would alternately mention that the rate of diffusion is proportional to the concentration difference between either side of the membrane.
eBook - PDF- Walter G. Berl(Author)
- 2013(Publication Date)
- Academic Press(Publisher)
What is written here concerning the properties of membranes and their preparation is, of course, applicable to these other two techniques. 2* General Theory and Background 2.1. MECHANISM OF Dialysis 2.1.1. Description of the Process. A setup for Dialysis is shown in diagrammatic form in Fig. 1. Fig. 1(a) represents the situation at the beginning of the Dialysis. In one compartment there is the solution to be dialyzed containing two solutes of different size, and in the other compart-ment there is pure solvent. The membrane, M, is a thin sheet of material placed between the two compartments which will prevent gross mixing by stirring or convection. It also must have the property of being readily perme-able to the solvent and the smaller solute and impermeable to the larger solute. After this system has stood for some time, the change that occurs is shown in Fig. 1(b). Much of the smaller solute has diffused into the com-partment at the right, (diffusate) leaving the larger solute in the compart-ment at the left (dialyzate). If the diffusate is replaced with pure solvent Dialysis 3 from time to time, a complete separation will eventually be obtained. The volume of the dialyzate will usually increase due to the difference in osmotic pressure between the two compartments. Dialysis is a very mild procedure for making separations and in its simplest form may be looked upon as analogous to separations made by mechanical sieves. The substances being separated are in a liquid solution, and a membrane acts as the sieve. The only real difference is in the driving force. In mechanical sieving, gravity is the driving force which compels the smaller particles to move through the sieve, whereas in Dialysis the driving force is the concentration gradient. Thus there are two principal factors which govern the passage of a substance through a membrane, the diffusion coefficient of the substance and the size of the openings (pores) in the membrane.
eBook - PDFTrauma
Critical Care
- William C. Wilson, Christopher M. Grande, David B. Hoyt, William C. Wilson, Christopher M. Grande, David B. Hoyt(Authors)
- 2007(Publication Date)
- CRC Press(Publisher)
Therefore, it appears that volume overload tends to confer a poorer prognosis. This notion is supported by a number of observational studies. For 759 example, recent studies have suggested that achieving a negative fluid balance in the first three days of admission for septic shock is a predictor of better survival (14). More- over, hypervolemia is a common accompaniment to perio- perative ARF. Mukau et al. (15) showed that 95% of their patients with postoperative acute renal failure had fluid excesses of more than 10 L at initiation of Dialysis. Consequently, fluid regulation ought to be an import- ant consideration when deciding to initiate Dialysis in the ICU patient with ARF. Such renal support provides volume “space,” which permits for the administration of adequate nutritional support without limitations (16). In addition to volume overload, solute disturbances such as hyperkalemia may predispose to life-threatening dysrrhyth- mias, and uncontrolled uremia may lead to a variety of serious complications. Thus, maintaining electrolyte, acid – base, and solute homeostasis is another important factor when considering initiation of Dialysis. PRINCIPLES OF Dialysis Overview Dialysis is a process in which molecules in solution “A” (blood) diffuse across a semipermeable membrane into sol- ution “B” (dialysate) (6). The transfer of solute across the membrane is determined by membrane characteristics and the solute concentration on the two sides of the membrane. Diffusive clearance denotes the movement of small mole- cular weight solutes from plasma to dialysate under the driving force of an electrochemical gradient. Convective clearance (ultrafiltration, UF) occurs when water is driven across the membrane by either a hydrostatic or an osmotic force. Those solutes that can pass through the membrane pores move along with the water (solute drag). Determinants of Diffusive Clearance Membrane characteristics play a major role in determining the efficacy of diffusive clearance.
- Andrew Wood(Author)
- 2016(Publication Date)
- CRC Press(Publisher)
327 13 Renal Biophysics and Dialysis Andrew W. Wood The kidneys are vital to the maintenance of equilibrium between the food and drink we consume and the excretion of fluid in the form of urine. We also lose fluid through perspiration and, to a lesser extent, respiration. The kidneys and associated control systems are able to monitor fluid balance and, by extension, circulatory blood volume. In more primitive animals, such as amphibia, the skin also is a major component in the regulation of fluid balance, so a portion of what is now known about the function of the human kidney has been inferred from the effects of hormones and other agents on the rate of ion CONTENTS 13.1 Kidney Function ................................................................................................................ 328 13.1.1 Kidney Structure .................................................................................................... 328 13.2 Kidney Function Tests: Formulae .................................................................................... 333 13.2.1 Renal Clearance ...................................................................................................... 333 13.2.2 Glomerular Filtration Rate .................................................................................... 334 13.2.3 Effective Renal Plasma Flow ................................................................................ 334 13.2.4 Tubular Reabsorption and Secretion .................................................................. 334 13.2.5 Maximal Tubular Reabsorption and Secretion ................................................. 335 13.2.6 Renal Plasma and Blood Flow ............................................................................. 336 13.2.7 Filtration Fraction ...................................................................................................
eBook - ePub- Anthony Atala, Robert Lanza, Robert Nerem, James A. Thomson(Authors)
- 2011(Publication Date)
- Academic Press(Publisher)
Wolfe et al., 1999) . HemoDialysis provides clearance of small molecules in blood by diffusive flow across a semipermeable membrane, and control of volume status by bulk flow of water and solutes through that membrane. These short-term effects are sufficient to abrogate the lethal acidosis, volume overload, and uremic syndromes which accompany renal failure but do not protect the patient from the increased mortality associated with Dialysis-treated renal failure in either the acute or chronic form. Thus the metabolic, endocrine, and immune roles of the functioning kidney are candidate mechanisms for the difference in survival noted above. The dialytic clearance of glutathione, a key tripeptide in free radical scavenging and protection against oxidant stress, the negative nitrogen balance and energy loss in the clearance of peptides and amino acids in dialysate, loss of oxidative deamination and gluconeogenesis in the tubule cell, and loss of cytokine and hormone metabolic activity by the kidney each impose substantial stress upon the dialyzed patient and as such are appropriate targets for improved renal replacement therapy to the host that intermittent hemoDialysis does not address. The kidney’s functional unit, the nephron, provides for the elimination of wastes and toxins without the need for specific enzymes and transporters for each toxin. All but the large proteins and cellular elements in the blood are filtered, and a system of cells reclaims filtered substances needed by the body, and allows all others to pass as urine. Teleologically, this allows each organism to cope with novel insults its genetic forebears may not have encountered.Filtration is accomplished by the glomerulus, a tuft of capillaries supported by a basement membrane and specialized epithelial cells called podocytes. The renal proximal tubule, a hollow tube of cells surrounded by capillaries, receives the filtrate from the glomerulus and accomplishes the bulk of reclamation of salt, water, glucose, small proteins, amino acids, glutathione, and other substances. The tubule also accomplishes metabolic functions, including excretion of acid as ammonia, hydroxylation of 25-hydroxy-vitamin-D3
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