Hemodialysis: What You Need to Know

  • Healthy kidneys clean your blood and remove extra fluid in the form of urine.
  • They also make hormones your body needs for some important functions.
  • It balances electrolytes, control blood pressure & maintain acid-base balance.
  • When kidney failure occurs, treatment is needed to replace some of the important jobs your kidneys do.
  • The treatments for kidney failure are hemodialysis, peritoneal dialysis and kidney transplant.

1. When will the patient need to start treatment?

  • Treatment is needed when someone has stage 5 chronic kidney disease ( CKD ), or kidney failure.
  • Your doctor can tell your stage of CKD by checking your glomerular filtration rate ( GFR ).
  • Your GFR can be estimated from the results of a blood test for creatinine, a waste product from muscle activity.
  • If your GFR falls below 15, you are said to have kidney failure ( CKD stage 5 ) , and you will need to have some form of treatment to replace the function of your kidneys.
  • If your GFR is less than 30, the doctor should talk to the patient about the different treatments for kidney failure.

2. What does dialysis does to keep the patient healthy?

  • Both the Hemodialysis and Peritoneal dialysis do the following :
    • Remove waste, salt and extra water to prevent them from building up in your blood
    • Keep a safe level of certain chemicals in your blood
    • Help to regulate blood pressure

3. How does hemodialysis work?

Hemodialysis: How it works?

  • A hemodialysis machine has a special filter called a dialyzer, or artificial kidney, to clean your blood.
  • To get your blood into the dialyzer, the doctor needs to make an access, or entrance, into your blood vessels.
  • This is done with minor surgery, usually to your arm.
  • Three different types of access can be made – a fistula, a graft or a catheter.
  • A fistula is the first choice for an access. It is made by joining an artery to a nearby vein under your skin to make a bigger blood vessels. This type of access is preferred because it has fewer problems and lasts longer. The patient should be evaluated by a special doctor called a vascular surgeon at least six months before they will need to start dialysis. A fistula should be placed early ( several months before starting dialysis ) so it has plenty of time to heal and be ready by the time they need treatment.
  • If the blood vessels are not suitable for a fistula, a graft may be used. This involves joining an artery and nearby vein with a small, soft tube made of synthetic material and placed under your skin.
  • After the fistula or graft has healed and dialysis is started, two needles will be placed- one in the artery side and one in the vein side of the access- everytime the patient will go for treatment. The needles are connected to plastic tubes. One tube carries your blood to the dialyzer where it is cleaned and the other tube returns the cleaned blood back to you.
  • The third type of access, called a catheter, is inserted into a large vein in your neck or chest. This type of access is generally used when patient needs dialysis for a short period of time. catheters may be used as a permanent access but only when a fistula or a graft cannot be placed. Catheters can be connected directly to the dialysis tubes and needles are not used.
  • The patient will be referred to a special surgeon for placement of access.

4. How does the dialyzer cleans blood?

  • The dialyzer, or filter, has two parts – one part for your blood, and the other part for a washing fluid called dialysate. A thin membrane separates these two sides. Blood cells, protein and other important things remain in your blood because they are too big to pass through the membrane. Smaller waste products such as urea, creatinine and extra fluid pass through the membrane and are removed. Changes in the dialysate or cleansing fluid can be made according to patients special needs.

Filtering Process

  • The dialyzer carries out the functions of an artificial kidney. It contains thousands of tiny hollow fibers, and blood flows through these fibers while the dialysis solution flows around them in the opposite direction. The fibers serve as a semipermeable membrane, meaning some substances can pass through it while others can’t.The flow of the blood and dialysate in opposite directions creates a concentration gradient such that in some portions of the fibers, wastes are in higher concentration in the blood and thus flow to the solution, and nutrients are in higher concentration in the solution and thus enter the blood. Potassium, phosphorus and urea are among the substances that are filtered out of the blood. Potassium and calcium flow into the blood if the blood levels are too low.
  • Excess water flows out of the blood and into the solution due to a pressure gradient that puts the solution at a lower pressure. The machine continually pumps fresh dialysate through the dialyzer and removes the used solution and the wastes it contains.

5. Where is Hemodialysis done?

  • Hemodialysis can be done at a hospital, at a dialysis center that is not part of a hospital or at home. The patient and the doctor will decide which place is best based on patient’s medical condition and their wishes.

6. How long will each Hemodialysis treatment lasts?

  • Hemodialysistreatments are usuallydone three times a week. Each treatment lasts about four hours, but you may need more time to ensure that enough wastes and fluid are removed. The amount of dialysis the patient needs depends on :
    • How much their kidneys are working
    • How much patient’s fluid weight gain between treatments
    • How much patient’s weigh
    • How much patient’s waste have in their blood
    • The type and size of artificial kidney used by the dialysis center
  • The doctor will give them a dialysis prescription that tells how much treatment they need. Studies have shown that getting the right amount of dialysis improves patient’s over-all health, makes them feel better, keeps them out of the hospital and enables them to live longer.

7. How the patient knows that they are getting the right amount of dialysis?

  • A special dialysis prescription will be developed for patient. This will help make sure that patient get the right amount of treatment. In addition, the dialysis care team should monitor the treatment with monthly lab tests to measure the amount of dialysis they receive ( delivered dose of dialysis ).
  • The most accurate way to measure this is called urea kinetic modeling. The number that tells the delivered dose of dialysis is the Kt / V.
  • The goal of the Kt /V number may vary depending on how often the patient should have dialysis and on how much remaining kidney function they have left.
  • For many dialysis patients who have three treatments weekly, Kt / V should be at least 1.2 for each treatment.
  • Other methods are sometimes used to measure delivered dose of dialysis. For example, some dialysis centers may use the urea reduction rate ( URR ). If this ratio is used to measure the delivered dose of dialysis, the URR should be at least 65 percent for each treatment.

Tip in knowing the delivered dose of dialysis.

  • The dialysis care team should make sure that :
    • Patient’s access is working well
    • Their dialyzer is working well
    • The blood flow and the flow rate of the dialysate fluid ( cleansing fluid ) are not too slow during dialysis.
    • The blood samples are taken correctly
  • · You can help to ensure that patient receive enough treatment by :
    • Arriving on time and staying for the full treatment
    • Keeping all their appointments

8. Can patient have dialysis at home?

  • Possibly. Many patients have their hemodialysis treatments at home. If the patient and the doctor decide this is a good choice for treatment, the patient and the dialysis care partner will be trained in how to do hemodialysis at home. The dialysis care partner will usually be a family member or friend but may also be someone they hire to assist the patient.
  • Home hemodialysis allows to schedule patient’s treatments to fit their routine.
  • Patient’s home must have enough space for the equipment and enough water drainage and electric power to operate the dialysis machine and water purification unit.
  • Some newer methods of home hemodialysis are now available. These methods are called short daily home hemodialysis and nocturnal home hemodialysis. They involve either shorter, more frequent treatments or long, slow treatments during sleep. Many patients using these treatments have better control of blood phosphorus levels, blood pressure and anemia; better sleep; and improved quality of life.

Protecting the remaining kidney function

  • Take blood pressure pills called angiotensin-converting enzyme inhibitors ( ACEIs) or angiotensin receptor blockers ( ARBs) if the patient have high blood pressure. These medicines help to protect kidney function.
  • Avoid medicines that can harm patient’s kidneys, such as pain –relieving medicines called nonsteroidal anti- inflammatory drugs ( NSAIDs) and certain antibiotics.
  • Ask the doctor about taking diuretics ( water pills ) to help remove salt and water from patient’s blood.
  • Make sure conditions like diabetes and high blood pressure are well controlled.

9. Can dialysis cure patient’s kidney disease?

  • In some cases of sudden ( also called acute ) kidney failure, dialysis may only be needed for a short time until the kidneys get better. However, when CKD progresses slowly over time to kidney failure, the kidneys do not get better. The patient will need dialysis for the rest of their lives unless they will able to receive a kidney transplant.

10. How to stay comfortable on dialysis:

  • Symptoms like cramps, headaches, nausea or dizziness are not common during dialysis.
  • Slow down the patient’s fluid removal, which could increase the dialysis time
  • Check the high blood pressure medications
  • Adjust the dry weight or target weight
  • Cool the dialysate a little.
  • The patient can help themselves if by carefully following their sodium ( salt ) and fluid limits between treatments to decrease fluid buildup in your body.

11. Do patients need to follow a special diet?

  • Yes. Patient’s diet will be different from the one they followed before starting dialysis.
  • Although certain foods may be limited, it is important to get the right amount of protein and calories to maintain good health.
  • It is important to stick in patient’s fluid and sodium ( salt ) limits so patient will not build up too much fluid in their body between treatments. This build up may lead to the need for some fluid removal ( ultrafiltration ) during patient’s dialysis treatment.
  • Ultrafiltration may cause some discomfort during patient’s treatment.
  • Excess fluid build up can also increase patient’s blood pressure. To help prevent fluid buildup between treatments, patient’s daily diet should not include more than 2 grams of sodium, or 5 grams of salt.

Tip: Keep sodium under control

  • To limit the amount of sodium in patient’s diet and help prevent too much fluid buildup, try the following :
    • Cook with herbs and spices instead of salt
    • Read food labels; choose foods low in sodium
    • When eating out, order meat or fish without salt. Ask for gravy or sauce on the side because these may contain large amounts of salt and should be used in small amounts.
    • Limit use of canned, processed and frozen foods
    • Avoid salt substitutes and specialty low-sodium foods made with salt substitutes because these are high in potassium

12. Will Dialysis Change Patient’s Lifestyle?

  • Patient and the patient’s family needs time to get used to dialysis and their treatment schedule. The social worker in the dialysis center will be available to provide counseling to help the patient and patient’s family adjust to changes in their lifestyle caused by their illness.
  • Once the patient’s get used with their treatment, they should feel a lot better. In fact, they may feel more like doing the activities they enjoyed before their kidney disease developed.
  • Medications are available to treat their anemia and keep their bones healthy so they will feel stronger and less tired.


  1. Kt/V and URR – are measures of your delivered dose of dialysis. They tell whether you are receiving the right amount of dialysis.
  2. Glomerular filtration rate ( GFR ) – is an estimate of how well your kidneys are working, Your GFR can be measured from the results of patient’s blood creatinine test, patient’s age, gender and race.
  3. Albumin and normalized protein nitrogen appearance ( nPNA) – are measures of patient’s nutritional health. It tells whether patient’s are getting enough protein and calories from their diet.
  4. Hemoglobin is the part of red blood cells that carries oxygen to patient’s tissues. If patient’s number is too low, they have anemia and they will need to take a medicine to raise red blood cell production in their body.
  5. Transferring saturation (TSAT ) and serum ferritin are measures of the iron stores in their body. Iron is important to patient’s body’s ability to make red blood cells. They need extra iron if they have anemia.
  6. Parathyroid hormone ( PTH ) – is made by four small glands located in the neck. If these glands work too hard and make too much PTH, it may lose calcium from your bones. Over time, this can weaken their bones and cause them to break more easily.
  7. Calcium and phosphorus – are two minerals that are important for bone health. if they get out of balance, the parathyroid glands start making more PTH, which may lead to loss of calcium from the bones.
  8. Potassium is a mineral that is important to the heart. Too much or too little potassium in the blood may be harmful to the heart.
  9. Target weight ( or dry weight ) – is how much you should weigh after dialysis removes excess fluid from your body.
  10. Average daily weight gain – is the amount of weight you gain each day between dialysis treatments. If you do not follow your fluid and salt limits between treatments, you may gain too much fluid weight.
  11. Pre-dialysis and post-dialysis blood pressure – should be taken each time you receive dialysis. Your blood pressure goes down when excess fluid and salt are removed from your blood by your dialysis treatment.
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