Dialysis

Dialysis procedure

1. Dialysis By: Naseem abu hawas

2. Kidneys – Facts and Function The kidneys have three main functions: 1- Control concentrations of body fluids, 2- Rid the body of unwanted soluble waste 3- Regulate a proper acid-alkaline environment in the body for proper chemical reactions Even small variances may result in death.

3. Kidney Failure Kidney failure, or renal failure, occurs when the kidneys fail to function adequately . 1- Acute renal failure - Definition Acute renal failure (ARF) occurs when a rapid loss of renal function results in poor urine production, electrolyte disturbance, and fluid balance disturbance 2- Chronic Renal Failure - Definition Chronic renal failure (CRF) or chronic kidney disease (CKD) occurs when a progressive loss of kidney function occurs over a period of months to years.

4. Dialysis - Definition Dialysis is an artificial process used to remove water and waste substances from the blood when the kidneys fail to function properly. It generally works through osmosis and filtration of fluid across a semipermeable membrane with the use of a dialysate .   Principle : Dialysis works on the principles of the diffusion of solutes and ultrafiltration of fluid across a semi-permeable membrane. Diffusion describes a property of substances in water. Substances in water tend to move From an area of high concentration To an area of low concentration.

5.   Semipermeable Membrane - Definition A semipermeable membrane is a thin layer of material that contains various sized holes, or pores. Smaller solutes and fluid pass through the membrane, but the membrane blocks the passage of larger substances (for example, red blood cells, large proteins).   Dialysate –: Dialysate is a Solution containing ultra pure water and chemicals (electrolytes) that passes through the artificial kidney to remove excess fluids and wastes from the blood. Urea and other waste products, potassium, and phosphate diffuse into the dialysis solution. Concentrations of sodium chloride are similar to those of normal plasma to prevent loss.

6. In medicine, a shunt is a hole or a small passage which moves, or allows movement of, fluid from one part of the body to another. The term may describe either congenital or acquired shunts; and acquired shunts (sometimes referred to as iatrogenic shunts) may be either biological or mechanical.

7. Catheter (shunt)Types: Catheters are usually found in two general varieties, tunnelled and non- tunnelled . 1-Non-tunnelled catheter access is for short-term access Up to about 10 days Often for one dialysis session only Catheter emerges from the skin at the site of entry into the vein.

8. 2-Tunnelled access involves a longer catheter Tunnelled ” under the skin From the point of insertion in the vein exit site some distance away placed in the internal jugular vein Exit site is usually on the chest wall. The tunnel acts as a barrier to invading microbes, and as such, tunnelled catheters are designed for short- to medium-term access (weeks to months only), because infection is still a frequent problem.

9. Example of shunt : Cardiac shunts  may be described as right-to-left, left-to-right or bidirectional, or as systemic-to-pulmonary or pulmonary-to-systemic. Cerebral shunt : In cases of  hydrocephalus  and other conditions that cause chronic increased  intracranial pressure , a  one-way valve  is used to drain excess  cerebrospinal fluid  from the  brain  and carry it to other parts of the body. This valve usually sits outside the  skull , but beneath the  skin , somewhere behind the  ear .

10. Lumbar-peritoneal shunt : In cases of chronic increased  intracranial pressure  such as   Hydrocephalus , a tube or shunt with or without a  one-way valve  is used to drain the excess  cerebrospinal fluid  from the  brain  and transport it to the peritoneal cavity, which is a cavity located in the abdomen area of the body. This  shunt  is usually inserted in between two of the vertebrae in the lumbar and punctures the cerebrospinal fluid sack or lumbar subarachnoid space, it then runs beneath the  skin  to the peritoneal cavity, where it is eventually drained away by the normal bodily fluid drainage system. [ A  Peritoneovenous shunt :  is a shunt which drains  peritoneal fluid  from the  peritoneum  into  veins , usually the  internal jugular vein  or the  superior vena cava .

11. Catheter Problems 1- Infection (frequent) tunnelled catheters are designed for short-to medium-term access weeks to months only Venous Stenosis (serious) Foreign body in the vein 2- Venous stenosis Results in scarring and narrowing of vein 3- Can cause problems with severe venous congestion in the area drained by the vein

12. How dialysis is performed There are two main types of dialysis: haemodialysis and peritoneal dialysis. 1-Haemodialysis involves diverting blood into an external machine, where it's filtered before being returned to the body 2- Peritoneal dialysis involves pumping dialysis fluid into the space inside your abdomen (tummy) to draw out waste products from the blood passing through vessels lining the inside of the abdomen.

13. Haemodialysis Preparing for treatment Before haemodialysis start ,  will usually need to have a special blood vessel created in patient arm , called an arteriovenous fistula (AV fistula). This blood vessel is created by connecting an artery to a vein. Joining a vein and an artery together makes the blood vessel larger and stronger. This makes it easier to transfer your blood into the dialysis machine and back again. The operation to create the AV fistula is usually carried out around four to eight weeks before haemodialysis begins. This allows the tissue and skin surrounding the fistula to heal. If blood vessels are too narrow to create an AV fistula, an alternative procedure known as an AV graft may be recommended. A piece of synthetic tubing (graft) is used to connect the artery to the vein. As a short-term measure , or in an emergency , you may be given a neck line. This is where a small tube is inserted into a vein in your neck.

14. The haemodialysis process Most people need three sessions of haemodialysis a week, with each session lasting around four hours. This can be done in hospital Two thin needles will be inserted into AV fistula or graft and taped into place. One needle will slowly remove blood and transfer it to a machine called a dialyser or dialysis machine. The dialysis machine is made up of a series of membranes that act as filters and a special liquid called dialysate . The membranes filter waste products from blood, which are passed into the dialysate fluid. The used dialysate fluid is pumped out of the dialyser and the filtered blood is passed back into your body through the second needle. During your dialysis sessions, you will sit or lie on a couch, recliner or bed. You will be able to read, listen to music, use your mobile phone or sleep. Haemodialysis isn't painful , but some people feel a bit sick and dizzy, and may have muscle cramps during the procedure. This is caused by the rapid changes in blood fluid levels that occur during the treatment. After the dialysis session, the needles are removed and a plaster is applied to prevent bleeding. If you were treated in hospital, you can usually go home shortly afterwards.

15. Peritoneal dialysis There are two main types of peritoneal dialysis: 1- continuous ambulatory peritoneal dialysis (CAPD )  – where blood is filtered several times during the day 2- automated peritoneal dialysis (APD)  – where a machine helps filter blood during the night as patient sleep Both treatments can be done at home once patient trained to carry them out himself .

16. Preparing for treatment Before have CAPD or APD, an opening will need to be made in abdomen. This will allow the dialysis fluid ( dialysate ) to be pumped into the space inside your abdomen (the peritoneal cavity). An incision is usually made just below belly button. A thin tube called a catheter is inserted into the incision and the opening will normally be left to heal for a few weeks before treatment starts. The catheter is permanently attached to abdomen, which some people find difficult.

17. Dialysis and pregnancy Becoming pregnant while on dialysis can sometimes be dangerous for the mother and baby. It's possible to have a successful pregnancy while on dialysis, but will probably need to be monitored more closely at a dialysis unit and may need more frequent or longer treatment sessions.