extracorporeal Devices

M Asif Raza10-NTU-6010

Department of TextilesNational Textile University Faisalabad

Medical Textiles

• Medical textiles are textile products and constructions for medical applications.

• They are used for first aid, clinical or hygienic purposes and rehabilitation.

Market Share

• Share of technical textiles is 23.8mn tones with a value of $126bn by 2010.

• Share of Medical textiles is 2.4mn tons with a value of US$8.2bn by 2010.

Categories of Medical Textiles• Protective and Healthcare Textiles -

Surgical Wear, Operation Dresses, Staff Uniforms, etc.• External Devices -

Wound Dressings, Bandages, Pressures Gauze, Prosthetic Aids, etc.

• Implantable Materials - Sutures, Vascular Grafts and Artificial Limbs are the products where textiles are used.

• Hygiene Products - Incontinence pads, Nappies, Tampons, Sanitary Towels, etc.

• Extracorporeal Devices - Artificial Liver, Artificial Kidneys, and Artificial Lung are the recent advances in Medical Textiles.

Extracorporeal Devices

• It is a man-made device that is implanted or integrated into a human to replace a natural organ, for the purpose of restoring a specific function or a group of related functions so the patient may return to as normal a life as possible.

• These include Artificial Kidney, Liver and Lungs.

Artificial Liver

• The liver is a remarkable organ; like the skin.• it can regenerate after severe trauma. In fact, a patient can recover

with only 20% of his or her liver still functional. As the liver grows back.

• However, there is a point of ‘no return’ after which the liver cannot regenerate, and there are underlying disease conditions that, in some cases, make a transplant the only alternative.

Liver Functions

• Unlike the heart, lung or kidney, which have one primary function, the liver has multiple functions essential to maintain life including carbohydrate metabolism, synthesis of proteins, amino acid metabolism, urea synthesis, lipid metabolism, drug biotransformation and waste removal.

• Therefore the preferred artificial liver support system would perform these various liver functions.

Artificial Liver

• Earlier, artificial support systems were not widely used in cases of liver failure, primarily because hepatic toxins are albumin-bound unlike for the most part uremic pollutant and hence cannot be removed by usual dialysis process.

Fiber Used & Function

• Hollow polypropylene fiber, hollow silicone membrane

• Separate and dispose of patients’ plasma and supply fresh plasma

Artificial Kidney

• The kidneys serve as filtering devices of the blood. The nephrons, the working units of the kidney, filter waste materials out of the blood and produce urine to secrete toxins from body. The kidneys also maintain normal concentrations of body fluids, which play a key role in homeostasis.

• Kidney failure - affects 200 000 patients worldwide

Function

• The function of the artificial kidney is achieved by circulating the blood through a membrane, which may be either a flat sheet or a bundle of hollow regenerated cellulose fibers in the form of cellophane that retain the unwanted waste materials.

• Blood purification is an effective therapy for incurables such as end-stage renal failure.

Principle of Blood Purification

• Principles of blood purification therapies are dialysis, filtration and adsorption. Separation membranes and adsorbents are used in blood purification devices.

Working• High efficient hollow fibers have replaced

coil or laminate in dialyser devices. The cross-section of a hollow fiber-type dialyser is shown in Figure, which consists of 4,000 to 20,000 hollow filaments having an external diameter of 200 to 300 micrometer. Blood flows inside of the fibres and the dialysate flows outside of the fibres. Almost the same materials are used for hemofiltration. The term 'Artificial kidney' is often applied to the whole system including the pumps and control circuitry for the dialysate mixing and delivery, and for the blood preparation and monitoring, pumping, deaerating and return to the body.

The End