What is Dialysis?

Kidneys are a pair of bean shaped organs located on either side of the spine. A kidney filters the blood by flushing out metabolic waste products and excess fluids from the body.  But when the kidneys stop functioning, dialysis is the alternative used to restore the filtration process of the blood in the body. Dialysis is the procedure which diverts the blood to a dialyzer (which performs similar functions as the kidneys) to remove the harmful waste substances and excess fluids from the body.

What does dialysis do?

Dialysis keeps the body in equilibrium when the kidneys fail to function normally. The following can be achieved through dialysis: 

  • It removes the waste products, excess salts and water to prevent their build-up in the body.
  • Helps to control and maintain blood pressure in the normal physiological range.
  • Maintains the optimum levels of chemicals in the body such as sodium, potassium and bicarbonates.

When is dialysis recommended?

A Nephrologist will recommend dialysis in the presence of either of the below conditions:  

  • End stage renal disease or chronic renal failure
  • Advanced acute kidney injury

Types of Dialysis

There are two types of Dialysis:

  • Hemodialysis
  • Peritoneal dialysis


Hemodialysis is the most commonly used method of dialysis. It uses a specially designed artificial kidney called hemodialyzer to remove waste substances and harmful chemicals from the blood. During hemodialysis, blood leaves the body through the vascular access, gets filtered by hemodialyser and returns through the body via the vascular access. Vascular access may be an AV fistula, AV graft or a central venous catheter. The vascular access will be done by the following ways:

  • The doctor will connect an artery to the vein to form a new large blood vessel called fistula.
  • The doctor will join the artery to the vein together by using a small plastic tube, called grafting. 
  • The doctor will insert a special thin plastic tube into the large vein in the groin area or the neck; this type of vascular access is temporary.

The procedure is carried out in a special dialysis center in the hospital or in the home.

During dialysis, the doctor/nurses will clean the area of graft or fistula and insert two needles. Prior to this, the blood vessel in the groin area or arm should be enlarged to insert the needles. One tube carries the blood to the hemodialyser to filter the harmful substances and excess fluids in the blood. The other tube carries the filtered blood back to the patient from the machine.

The dialysis team will frequently monitor the patient’s blood pressure while the procedure is being performed. 

The hemodialysis procedure may last for up to 3-4 hours but sometimes it may differ from person to person based on the functioning of the kidney and also the amount of fluid gained by the patient between the treatments. The hemodialysis can also be done at home, called home hemodialysis. This can be done three times or more based on the patient’s kidney function.

Peritoneal dialysis:

In peritoneal dialysis the blood is cleaned within the patient’s body itself. In this method the lining of the abdominal wall or peritoneum acts as a filter to clean the blood. To conduct peritoneal dialysis, a minor surgery is performed to get access into the peritoneal cavity.

A small incision will be made at the side of the belly button to insert a plastic tube called catheter. The catheter is inserted into the region surrounding the stomach and other nearby organs. 

The peritoneal dialysis treatment will be performed in three main steps.

  • Fill: In this step, a sterile solution called dialysate which is rich in glucose and minerals is flowed through the catheter in to the peritoneal cavity in which the peritoneal membrane acts as a semi-permeable membrane.
  • Dwell: The waste products and excess fluid in the blood is filtered through the peritoneal membrane and pulled in to the dialysate. The extent of time the dialysate is present in the peritoneal cavity is called Dwell time.
  • Drain: The waste products and the excess fluids will be removed from the body when the dialysate is drained.

The process takes about 30-40 minutes to complete. The patient may require four exchanges in a day. The process of filling and draining is called exchange.

There are two main types of peritoneal dialysis:

  • Continuous Ambulatory Peritoneal Dialysis (CAPD): It does not require a machine. The patient can carry-out his/her regular activities or sleep when the dialysate is passed in to the catheter.
  • Continuous Cycler-assisted Peritoneal Dialysis (CCPD): The CCPD needs a machine named cycler to fill and drain the dialysate solution.

What are the precautions to be taken during dialysis?

  • Take erythropoietin and vitamin supplements as prescribed by the doctor to replace the hormones that are generally prepared by the kidneys. 
  • Take iron supplements and folic acid to produce red blood cells and prevent anemia.
  • Take calcium supplements to treat bone diseases which may occur due to the kidney failure.
  • Take the diet as suggested by the nephrologist. Avoid consuming food items rich in potassium, phosphorus, salt and restrict excessive fluid consumption. 
  • Notify the doctor if you have symptoms like fever, chills, skin itches and cough.
  • Report to emergency department immediately if you observe:
    • Bluish or pale tinge in fingers
    • Increased heart rate and breathing 
    • Dizziness or light headedness
    • Chest pain
    • Vomiting
    • Very little to no urine is passed 

Quick Enquiry


Dr. Ajay Shetty.

Senior Consultant - Urology & Andrology

Dr. Sushma Rani Raju.

Consultant - Nephrology

Dr. Venu Madhav Reddy G..

Associate Consultant - Nephrology

Dr. Girish G Nelvigi.

Senior Consultant – Urology and Andrology
Book Appointment With Dr. Girish Nelivigi,Andrologist,Consultant Urologist

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