Your kidneys help filter waste, excess fluid, and toxins from your blood. They are also important for blood cell production and bone health. If kidneys don't work properly, harmful substances build up in the body, blood pressure can rise, and too much fluid can collect in the body's tissues, which leads to swelling, called edema.
What Is Kidney Dialysis?
Kidney dialysis is a life-support treatment that uses a special machine to filter harmful wastes, salt, and excess fluid from your blood. This restores the blood to a normal, healthy balance. Dialysis replaces many of the kidney's important functions.
There are different types of kidney dialysis, including:
- Hemodialysis. Blood is filtered using a dialyzer and dialysis machine.
- Peritoneal dialysis. Blood is filtered inside the body after the abdomen is filled with a special cleaning solution.
Hemodialysis and the Kidneys
During hemodialysis, you will be hooked up to a machine that takes over the kidneys' job of filtering blood. Before the first session, the doctor will need to create an entrance into one of your blood vessels so your body can be connected to the filtering machine during each visit. This is called a vascular access. It is a place on your body where blood can be removed and then returned. This can be done by:
- Connecting an artery to a vein to create a larger blood vessel area, called a fistula
- Joining (grafting) an artery and vein together using a soft plastic tube
- Inserting a thin plastic tube into a large vein in the neck or groin area of the leg; this type of access is temporary.
You may need temporary or permanent access. The type of access and how long you need it depends on your individual condition. Experts recommend creating an access weeks or months before your first dialysis session so it has a chance to heal properly before using it.
During a hemodialysis session, your blood flows a little bit at a time through a special filter inside the machine. The filter removes wastes and extra fluids from your blood, but retains the proper balance of minerals such as potassium and sodium. Once the blood is cleaned, it is returned to the body.
Patients often need dialysis treatments several times a week. How long each hemodialysis session lasts depends on:
- How well your kidneys work
- How much fluid you gained since your last dialysis session
- How much waste has gathered in your blood since your last dialysis session
- Your weight
- The type of hemodialysis machine being used
Peritoneal Dialysis and the Kidneys
Peritoneal dialysis cleans the blood using the lining of your abdominal area as a filter. This method allows your blood to be cleaned while you sleep, while you work, or while you perform your everyday activities.
Before your first peritoneal dialysis session, you will need surgery so that your doctor can create access into your abdominal area. The surgeon will make a small surgical cut, most often to the side of your belly button. A plastic tube called a catheter is inserted through this access into the area surrounding the stomach and nearby organs. This is called the peritoneal cavity.
When it is time for dialysis treatment, you will place a cleaning solution called dialysate into the catheter. Your health care team will show you how.
A peritoneal dialysis treatment will consist of three steps:
- Fill: The dialysis solution flows through the catheter into your belly.
- Dwell: Waste products and extra fluid in your blood pass through the thin tissue lining the peritoneal cavity and are pulled into the dialysis solution. The amount of time the dialysis solution is in your belly is called the "dwell time." Dwell times may range from four to six hours.
- Drain: The wastes and extra fluid are removed from your body when you drain the dialysis solution.
The draining and filling process, called an exchange, takes about 30 to 40 minutes. You may need four exchanges a day. There are two main types of peritoneal dialysis. Each has a different exchange schedule.
- Continuous Ambulatory Peritoneal Dialysis (CAPD). This type of dialysis is done without a machine. You place the dialysis solution into your catheter and go about your everyday activities or sleep. It is done four or five times a day.
- Continuous Cycler-assisted Peritoneal Dialysis (CCPD). This type of dialysis uses a machine called a cycler to fill and drain the solution from your belly, usually while you sleep.
Who Needs Kidney Dialysis?
Kidney dialysis is a necessary treatment for people with end-stage kidney disease or permanent kidney failure. You need dialysis if you've lost about 85% to 90% of your kidney function. Temporary dialysis may be needed in some cases.
Hemodialysis is most commonly used to treat people with end-stage kidney disease. However, children who need dialysis often receive peritoneal dialysis.
What Should I Expect When on Kidney Dialysis?
The kidney dialysis treatment itself usually does not cause any pain or discomfort. However, some patients may develop low blood pressure, which can lead to headache, cramping, nausea, and vomiting. This usually goes away after a few treatments.
If you are on dialysis, you may also feel like:
- You have less energy. Dialysis can cause you to feel tired.
- You are depressed. Depression is a common problem among many patients on dialysis, but it can often be treated. Talk to your health care provider if you are feeling depressed.
- You may also feel like you have less time to get things done. Kidney dialysis requires strict scheduling and adjustments to lifestyle, which can disrupt your ability to work or enjoy everyday activities. This may be frustrating for you or your family. Counselors may be able to help you cope.
Most patients on hemodialysis require treatments three times a week for three to five hours or more a day. This is often done at a dialysis center or hospital, although some patients on hemodialysis -- along with a family member or friend -- may be taught how to perform the procedure at home. Your health care provider will discuss your options and determine which setting is best for you.
Patients who are on peritoneal dialysis have a little more independence, since this type does not have to be done at a clinic. It can be performed while you go about your daily activities or sleep.
Catheter-related infections are a common concern for people who are on peritoneal dialysis. Keeping your catheter area clean and bacteria-free helps prevent dangerous infections. If an infection affects the peritoneal cavity, you will not be able to continue with peritoneal dialysis. Tips for preventing an infection include:
- Always wash your hands before touching your catheter.
- Wear a surgical mask when performing an exchange.
- Use an antiseptic wipe to clean your access site.
- Check your supplies for signs of contamination.
Diet Considerations During Dialysis
If you have kidney disease, your doctor has likely recommended changes to your diet. Following a kidney disease-specific diet is very important to the success of your dialysis treatment. Diets can differ depending on the type of dialysis you get. Your kidney specialist -- or nephrologist -- will advise you on what dietary measures you need to take. For example, you will likely need to limit fluids and salt. Keep in mind that fluids aren't just found in drinks. Soups, fruits, and even ice cream contain plenty of water than can affect your body's water balance.
You may also be told to limit foods that are rich in phosphorus and potassium and to eat a high-protein diet. Before making any diet changes, talk to your health care team. They can provide further information on diet during dialysis.
How to Know if Kidney Dialysis Is Working
You will have blood tests done at regular intervals to determine if kidney dialysis is removing enough wastes from your body. Your health care provider will specifically look at the level of blood urea nitrogen (BUN), which provides an overall measurement for the amount of waste products in your body. Electrolytes such as sodium, potassium, calcium, and bicarbonate will also be monitored.
What Happens if I Stop Kidney Dialysis?
Dialysis is not a cure for kidney failure. If you stop dialysis, your kidneys will continue to fail. You cannot live without at least one functioning kidney, unless you get a kidney transplant. Without a kidney transplant, you will need dialysis for the rest of your life.