Hemodialysis Membranes

For Engineers to Medical Practitioners

Sirshendu De, Anirban Roy

• Publisher: CRC Press
• Year: 2017
• ISBN:
  9781351642842
• Edition: 1
• Topic: Medicine
• Subtopic: Biotechnology in Medicine

Book initiates with introductory material to hemodialysis technology and its historical evolution and later on divulging into the field of biomaterials. With this background, the book discusses selection criteria of a suitable biomaterial for synthesis of haemodialysis membranes along with illustration of a complete indigenous, low cost technology for spinning of haemodialysis fibres. Well illustrated description of instruments used for membrane characterization and biomedical engineering is also provided at suitable junctures to effectively present the concept including worked out examples. Present title can be a good textbook as well as a research material for membrane as well as biomedical engineering curricula and provides coverage for appropriate undergraduate and graduate students interested in hemodialysis membranes.

1

Kidney Function and Uremia

I could prove God statistically. Take the human body alone—the chances that all the functions of an individual would just happen is a statistical monstrosity.

—George Gallup

1.1Kidney Function and Micturition

The human kidney performs a multitude of functions. Primarily, these functions include¹ the following:

1. Excretion of metabolic wastes—Metabolism produces a lot of waste products that need to be excreted from the body, in order to avoid accumulation. A few examples of such waste products are urea, creatinine, and other metabolites. Apart from these, kidneys also eliminate toxins like pesticides, drugs, and artificial food additives that are ingested.¹
2. Water and electrolyte balances and body fluid osmomolality—Homeostasis is the property of a system by virtue of which any external disturbance leading to disruption of a system can be adjusted by controlling specific parameters. Kidneys maintain the homeostasis of the human body by regulating water and electrolyte balance. Intake of water and electrolytes can increase or decrease, at times drastically, and it can also be prolonged. In such cases, the kidney maintains the overall balance of electrolyte and water content by adjusting the excretion rates accordingly.²
3. Arterial pressure regulation—This is maintained by controlling the water and sodium concentration in the blood. At times, short-term arterial pressure regulation is also carried out by manipulating vasoactive factors like rennin.²
4. Acid–base balance—The kidney maintains acid–base balance in tandem with the lungs and body fluid buffers. It helps in excreting acids (e.g., sulfuric acid, phosphoric acid) produced during protein metabolism.²
5. Hormonal secretion and balance—The kidneys produce the active form of 1,25-dihydroxyvitamin D₃, also known as calcitrol. Calcitrol is required for normal phosphate deposition on bones and calcium reabsorption in the gastrointestinal tract.²
6. Gluconeogenesis—The kidneys synthesize glucose from amino acids during prolonged fasting. This is known as gluconeogenesis.²

In this regard, it is essential to understand the functioning of the kidney. A basic cross-sectional view of the human kidney is depicted in Figure 1.1a. In general, impure blood from various organs of the human body is received by the kidneys. The toxins are then removed from the body via transport through nephrons in the form of water-soluble waste stream received by the urinary bladder.

Figure 1.1 (a) Kidney cross section, (b) single nephron, and (c) uremic toxin pathway and urine formation. (Adapted from Kidney: Important Organ of Human Body. http://humanbodyreviews.blogspot.in/, Access date : 2016, April 15.)

The single unit that determines the kidney's filtration is called a nephron (Figure 1.1b). In fact, the size of the kidneys in various species is often determined by the number of n...

Table of contents

• Cover
• Halftitle Page
• Title Page
• Copyright Page
• Contents
• Preface
• Authors
• Chapter 1 Kidney Function and Uremia
• Chapter 2 Evolution of Hemodialysis Technology
• Chapter 3 Biocompatibility and Biomaterials
• Chapter 4 Selection of Material for Dialysis Membrane
• Chapter 5 Spinning of Dialysis Grade Membranes
• Chapter 6 Postprocessing of Dialysis Membranes
• Chapter 7 Mathematical Modeling of Dialysis
• Chapter 8 Economics of Dialyzer Manufacturing: Commercialization
• Chapter 9 Conclusion: Future Trends and Scope
• Index