Our kidneys regulate body levels of water and minerals, and remove waste products. The kidneys also produce hormones like renin, erythropoietin and 1, 25-dihydroxycholecalciferol.
Dialysis is a life-saving treatment for kidney failure. It helps remove nitrogenous waste, extra fluid and minerals from the blood when kidneys can no longer function adequately.
Dialysis may be used in two main situations:
- Acute kidney injury (AKI): This is sudden onset kidney problem happening over hours or days. Some people need dialysis for a short time while their kidneys recover.
- End stage kidney disease (ESKD) or chronic kidney disease stage V (CKD V): This is the last stage of a progressive kidney disease (eGFR is less than 15).
Dialysis is of two types:
- Haemodialysis
- Peritoneal Dialysis
Dialysis is recommended when waste, fluid, potassium or acid accumulates in the body and cannot be managed safely with medicines, dietary changes or other treatments. It also depends on persistent/ worsening symptoms such as nausea, vomiting, loss of appetite, weight loss, itching, swelling, breathlessness, tiredness or confusion etc
HEMODIALYSIS
Hemodialysis is a technique whereby the patient’s blood is processed in special filters (dialysers) where they are exposed to a specially created fluid (dialysate) against a semipermeable membrane; thus helping to filter out the waste products from the blood via the process of diffusion. The process of removal of excess fluid from the body is known as ultrafiltration. Both processes happen simultaneously, the processed blood is then returned to the patient’s body. Each session lasts approximately 4 hours and International guidelines recommend at least 12 hrs of treatment per week.
Image source: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Access
In order to do hemodialysis, your care team needs a safe way to reach your blood - vascular access or dialysis access.
A V Fistula: A connection is made between an artery and a vein in the hand or arm. This is the preferred access because of minimal complications.
A V Graft: An artificial vein is used to connect an artery and a vein, usually in the arm. It may be associated with complications like thrombosis, stenosis etc
Catheter: A tube made of inert material is placed in a large vein, often in the neck, chest or groin. This may be used when dialysis needs to start quickly or while waiting for a fistula or graft to be ready. In some cases when a fistula or graft is not feasible a cuffed tunnelled catheter may be used as a long term access. Complications include infections, stenosis, thrombosis and loss of major veins.
Intradialytic complications
- Sudden fall in blood pressure
- Muscle cramps
- Headache
- Nausea
- Dizziness or weakness
- Feeling very tired after treatment
- Bleeding or bruising near the access
- Infection or blockage in the access·
Take care of your access
Report to the dialysis unit immediately in case of
- Bleeding from access site that will not stop
- Severe pain, swelling, redness, warmth, or drainage near your access
- A fistula or graft that stops buzzing or vibrating like usual
PERITONEAL DIALYSIS
Peritoneal dialysis relies on use of inner lining of the abdomen – known as peritoneum, to filter blood inside the body. A specially created dialysis solution—water with dextrose and other additives—flows from a bag through a catheter into the abdominal cavity. This dialysis solution absorbs wastes and extra fluid from the body. After a few hours, the solution and the waste are drained out the abdomen into an empty bag and a fresh bag of dialysis solution is instilled. This process is called an exchange.
Image source: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Access
A few weeks before the planned start of peritoneal dialysis, a specially designed catheter is surgically placed in the abdomen often below and a little to the side of the belly button.
Types of peritoneal dialysis
- continuous ambulatory peritoneal dialysis (CAPD)
- automated peritoneal dialysis (APD)
CAPD
Exchanges are done manually in a clean, well-lit place. Each exchange takes about 30 to 40 minutes. The solution in left in the abdomen for 6 to 8 hours - the dwell time. Generally, 3 exchanges per day are required. Each CAPD exchange takes about 30 minutes to perform and can be timed to be done around scheduled breaks for lunch etc.
APD
Exchanges are done with the help of a machine called the cycler. It fills and empties the abdomen three to five times during one cycle. Automated peritoneal dialysis can be done at night. Before going to sleep the cycler is connected and then disconnected the next day morning.
Complications
Possible problems from peritoneal dialysis include infection, hernia and weight gain.
One of the most serious problems related to peritoneal dialysis is infection. Infection can involve the skin around catheter exit site or can develop peritonitis. Bacteria can enter through your catheter during connection or disconnection.
Dialysis training
Patients and at least one family member or friend are trained to do exchanges and avoid infections. This takes about a week to 10 days and then most people can perform both types of peritoneal dialysis on their own. Training includes the correct way to connect & disconnect, assessment of UF volume, care of skin around the catheter - exit site, prevention of infections, watching out for potential complications etc. Both CAPD and automated peritoneal dialysis can be performed in any clean, private place, including at home, at work or when travelling.
Comparison
- Hemodialysis is often done in a health care setting, such as a dialysis centre or hospital. Peritoneal dialysis can be done at home, work or in any other space that is clean and dry. Therefore it is beneficial for people who have a job, travel or live far from a hemodialysis centre.
- Peritoneal dialysis is a more continuous therapy than hemodialysis and leads to less potassium, sodium and fluid accumulation in the body. This allows a more flexible diet and fluid intake pattern than hemodialysis.
- Better preservation of residual renal function in patients on peritoneal dialysis.
- Since there is no need for puncturing the fistula with needles before each dialysis sessions, there is no pain associated with peritoneal dialysis.
Dialysis Adequacy
With good quality dialysis there will be improvement in symptoms such as increased appetite, better quality of sleep, no breathlessness, no swelling, feeling energetic and overall better quality of life. People on dialysis can continue to work, go to school, care for family and continue other daily activities.
In addition, there are clinical markers indicating good quality dialysis including better blood pressure control, minimal interdialytic weight gain, maintained levels of haemoglobin, potassium, phosphorus, albumin etc. Certain parameters like URR, kt/v are studied for Hemodailysis adequacy and PET and clearance studies are done to assess adequacy of Peritoneal dialysis.
Dialysis is a form of renal replacement therapy. Dialysis can replace some functions of healthy kidneys, but it does not cure your kidney disease. It is also important to understand that dialysis does not replace the endocrine functions of failed kidneys. Therefore, patients need to take additional medications and precautions as well.
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