Objectives of Dialysis
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In medicine, dialysis is a type of renal replacement therapy that provides an artificial replacement for lost kidney function due to renal failure. It is a life support treatment and does not treat kidney diseases. Dialysis may be used for very sick patients who have suddenly lost their kidney function (acute renal failure) or for quite stable patients who have permanently lost their kidney function (end-stage renal failure). When healthy, the kidneys remove waste products (for example potassium, acid and urea) from the blood and also remove excess fluid in the form of urine. Dialysis treatments have to duplicate both of these functions as dialysis (waste removal) and ultrafiltration (fluid removal).
Dialysis works on the principle of the diffusion of solutes along a concentration gradient across a semipermeable membrane. In all types of dialysis, blood passes on one side of a semipermeable membrane, and dialysis fluid passes on the other. By altering the composition of the dialysis fluid, the concentrations of undesired solutes (chiefly potassium and urea) in the fluid are low and desired solutes (for example sodium) are at their natural concentration found in healthy blood. The undesired solutes then diffuse across the membrane into the dialysis fluid and are removed.
There are two main types of dialysis: hemodialysis and peritoneal dialysis. Hemofiltration is not strictly speaking a dialysis treatment but is remarkably similar.
The patient's blood passes through a system of tubing (a dialysis circuit) via a machine to a semipermeable membrane (dialyzer) with dialysis fluid running on the other side. The cleansed blood then returns to the body. Ultrafiltration occurs by increasing the hydrostatic pressure of the blood in the dialysis circuit to cause water to cross the membrane down a pressure gradient. The dialysis process is very efficient, allowing treatments to take place undertaken intermittently, usually three times a week. Sometimes large volumes of fluid must be removed in a session, which can often be demanding on the patient.
In peritoneal dialysis, a particular solution passes through a tube into the peritoneal cavity, the abdominal body cavity around the intestine, where the peritoneal membrane acts as a semipermeable membrane. The fluid remains for some time to absorb waste products and is then removed through the tube. This process is usually repeated several times a day. Ultrafiltration occurs via osmosis in this case, as the dialysis solution is supplied in varying osmotic strengths to allow for some control over the amount of fluid to be removed. This dialysis process is less efficient than hemodialysis and is carried out daily, but the ultrafiltration process is slower and gentler.
Hemofiltration is a similar treatment to hemodialysis, but the membrane is far more porous and allows the passage of a much larger quantity of water and solutes to pass across it. The fluid, which passes across the membrane (the filtrate), is discarded, and a special hemofiltration fluid replaces the desired solutes and fluid volume of the remaining blood in the circuits. It is a slow continuous therapy with sessions typically lasting 12-24 hours, usually daily. The ultrafiltration is thus gentle, making it ideal for patients in intensive care units where acute renal failure is a common problem. Hemofiltration is now also used for chronic treatment, particularly in Europe. By using large quantities of substitution fluids (60-90 liters per treatment), toxins and solutes can be removed from the patient. In theory, larger molecules will be removed by hemofiltration than standard hemodialysis. However, many studies are still in progress.
Usually, but not always. Some kinds of acute kidney failure get better after treatment. In some cases of acute kidney failure, dialysis may only be needed for a short time until the kidneys get better.
In chronic or end-stage kidney failure, your kidneys do not get better, and you will need dialysis for the rest of your life. If your doctor says you are a candidate, you may choose to get on a waiting list for a donor's kidney.
No. Dialysis does some of the work of healthy kidneys, but it does not cure a diseased organ. You will need lifelong dialysis treatments unless you have a kidney transplant
It's not a Painful process. You may feel some discomfort when the needles pierce into your fistula or graft, but few patients have other problems. The dialysis treatment itself is painless. Some patients may experience a drop in their blood pressure. If this happens, you may feel sick to your stomach, vomit, and have a headache or cramps. With frequent treatments, those problems usually go away.
If your kidneys have failed, you will need to have dialysis treatments throughout your life unless you can get a kidney transplant. Life expectancy on dialysis varies depending on other medical conditions and how well you follow your treatment plan. Average life expectancy on dialysis is 5-10 years, but many patients have lived well on dialysis for 20 or even 30 years. Our healthcare team will help you take care of yourself and stay healthy on dialysis.
Other than the time needed for treatments, many patients live perfectly normal lives. Dialysis makes you feel better because it helps many of the problems caused by kidney failure.
Absolutely. You must be on a special diet. You may not be able to eat everything you like, and you may need to limit how much you drink. Your diet may vary according to the type of dialysis.
Yes. Dialysis centers are available in most parts of the world, and treatments are reasonably standardized. You must make an appointment for dialysis treatments at another center before you go. The staff at your center may help you make the appointment.
Many dialysis patients can go back to work after they have gotten used to dialysis. If your job has a lot of physical labor (heavy lifting, digging, etc.), you may need to get a different job.
PDC aims to redefine and elevate the quality of renal-care in the Middle East and Africa region and offer comprehensive renal-care services. Its objective is to deliver quality, affordability and value in renal-care.