What is it about ?
The kidneys are made up of millions of microscopic filters (the glomeruli). Blood flows continuously through these filters. These filters permanently clean the blood: they rid the blood of excess waste and water, and keep the amount of salts within certain limits. What is in excess is evacuated via the urine.
Sometimes these filters are damaged. This destabilizes the water balance in the body. If the kidney filters keep getting damaged, they eventually don’t work at all. In this case, the waste remains in the blood, and it can be toxic to the body.
Dialysis is used to replace the function of the kidneys when the kidneys are only 10% or less functioning.
Severe kidney failure is almost always due to advanced kidney disease, such as kidney disease caused by diabetes (diabetic nephropathy), chronic inflammation of the kidney filters (chronic glomerulonephritis), cystic kidney disease (congenital cysts) in the kidneys) or hardening of the blood vessels in the kidneys (nephrosclerosis). These diseases are incurable. Once you are on dialysis, it is until the end of your life, unless you have a kidney transplant.
There are two types of kidney dialysis: hemodialysis and peritoneal dialysis.
Hemodialysis
Hemodialysis involves taking blood and purifying it by passing it through a machine.
A vascular surgeon first makes a connection between a vein and an artery in the wrist or forearm. This connection (arteriovenous fistula) is used to direct blood to the external machine, the “artificial kidney,” where the blood is purified and then returned to the body.
A dialysis session lasts an average of 4 hours; it usually takes place in the hospital. The number of sessions is approximately three per week. Today there are devices suitable for hemodialysis at home.
Peritoneal dialysis
Peritoneal dialysis involves using the peritoneum as an exchange membrane to remove waste products to a sterile liquid.
A tube (peritoneal dialysis catheter) is placed in the abdominal cavity laparoscopically.
Peritoneal dialysis is usually done at home by yourself. You first learn how to use the equipment in the hospital. The dialysis service is also available at all times in the event of a problem.
There are two types of peritoneal dialysis:
- Continuous ambulatory peritoneal dialysis (CAPD): you change the fluid 4 times in 24 hours, at regular intervals. You connect the bag (dialysate bag) to the catheter by following a sterile procedure. The fluid stays in the abdomen for several hours of the day or night. It loads in waste. You then drain the fluid out of your abdomen (drainage). And you replace it with new pure liquid.
- Automated peritoneal dialysis (APD): this is done for 8 to 10 hours at night while you are asleep. You connect at bedtime to an automatic cycler, which performs 4-6 fluid exchanges overnight. In the morning, the cycler finishes by filling the abdominal cavity with new fluid for the day.
This system therefore replaces kidney function more uniformly and consistently than hemodialysis.
A check-up takes place every 6 weeks in the hospital.
What is its frequency?
The number of people on dialysis is increasing due to the aging of the population. Belgium has around 7,000 dialysis patients, two thirds of whom are over 65 years old.
What should you watch out for?
Always be aware of possible complications, especially if dialysis is performed at home. Contact your doctor immediately if you have a fever, stomach ache, redness around the entrance to the catheter,accumulation of fluid (edema) in the legs or elsewhere.
Because your kidneys are not working properly, don’t drink too much. The amount you can drink is 800 ml in addition to the volume you urinate on the day. To detect excessive water loss or accumulation, it is best to weigh yourself daily. A rapid change in your weight indicates that something is wrong.
Strictly adhere to your diet, especially when it comes to salt. Check your blood pressure regularly, and write down the measured values. Always take your blood pressure on the other arm than the one with the fistula. It is very important to have good hygiene of the mouth and teeth. Prophylactic antibiotic therapy is necessary before scaling.
During hemodialysis, you may experience cramps towards the end of dialysis. If your blood pressure is too low, it probably means that too much fluid has been drawn out and you are dehydrated.
What can your doctor do?
The doctor is particularly attentive to a possible infection via the catheter. In peritoneal dialysis, this can lead to peritonitis, the first symptoms of which are abdominal pain and cloudy drainage fluid. Fever indicates a possible severe generalized infection (sepsis). In this case, the doctor will immediately send you to the hospital.
Fluid buildup (edema), shortness of breath, high blood pressure, or abnormalities on the x-ray of the lungs indicate fluid overload and are treated with dialysis. Patients on hemodialysis may also need to limit their fluid intake. In patients whose kidneys are still producing urine, high-dose diuretics may help.
In a hemodialysis patient, the general practitioner cannot take a blood test or take the blood pressure in the arm where the fistula is located. If he prescribes medication, he ensures that the type of medication and dosage are appropriate for the kidney failure.
Influenza vaccination is recommended annually for dialysis patients.
Want to know more?
- Hospital hemodialysis, here, Where to find on this page of Cliniques St Luc UCL
- How to organize your hemodialysis vacation – Hôpital Erasme ULB