Kidney Dialysis

Dialysis is the artificial replacement for renal failure. It can be processed to the patients of acute kidney failure (very ill patients who have suddenly lost their kidney function, which is temporary case.) and end stage renal failure (where people have lost their kidney function permanently) Dialysis is performed at dialysis unit or at home. It is a costly process.

Dialysis follows following principles in its working-

  • Diffusion
  • Osmosis of solutes and fluid at the other side of semi permeable membrane


Healthy kidneys can clean your blood and produce the hormones that make your bones strong. They also keep your blood healthy. On kidney failure you have to take replacement for all this work.

There are two options available for you:
Either you can have kidney transplant or dialysis. If you reject transplant, then you must accept dialysis.

Acute Indications for Dialysis/Hemofiltration:

  • In patients without renal failure, acute poisoning with a dialysable drug,
  • Fluid overload (which usually manifests as pulmonary oedema)
  • Hyperkalemia
  • Uremic pericarditis, a potentially life threatening complication of renal failure
  • Metabolic Acidosis

Chronic Indications for Dialysis:

  • Difficulty in medically controlling serum phosphorus or anemia when the GFR is very low
  • Low glomerular filtration rate (GFR) (RRT often recommended to commence at a GFR of less than 10-15 mls/min/1.73m2)
  • Symptomatic renal failure.


There are two main types of dialysis:

  • Hemodialysis process
  • Hemodialysis process is carried out with the machine. An entrance is made with a small surgery in your arm or leg. Sometimes a bigger blood vessel is made with a joint of artery and vein, named as fistula.
  • Pumping of human blood is carried out through a dialyzer blood compartment and it is exposed to a semipermiable membrane. A negative pressure is applied to the dialyzer's dialysate compartment. It causes wastes and water moving from blood to dialyste and removes liters of fluid in 3 to 5 hours.
  • It is given at dialysis center 3 times per week.

Peritoneal dialysis

In peritoneal dialysis, lining of your abdomen, known as peritoneal membrane is used. Through a tube a sterile solution of minerals and glucose is run into a cavity around intestine. Peritoneal membrane works as a semi permeable membrane here.Dialysate absorbs water products and wastes and drained out through a tube. During a day process is carried out for 4 to 5 times.Ultrafilteration technique is used there by osmosis. The fluid flows from blood to dialysate as a result of osmic pressure. It has a less efficiency than hemodialysis.Its net effect for removing salt, water, and waste products is same to hemodialysis.
There are two types of peritoneal dialysis.

  • Continuous cycling peritoneal dialysis (CCPD) carried out with a cycler machine at home. It is done at night when you sleep and numbers of cycles involve here.
  • Continuous Ambulatory peritoneal dialysis (CAPD)- It is done by yourself five times a day. Through a catheter, a bag of dilysate is put into your peritoneal cavity. It longs for 4 o 5 hours. After completion bag is thrown away. A new bag is used each time. Benefits of peritoneal dialysis
  • Can be carried out home by patient
  • Can be done while traveling
  • No specialized equipments are necessary.
  • No fix schedule or no need to go to dialysis clinic
  • Requires inspiration but not much essential

There is a process, similar to hemodialysis called Hemofiltration. A different principle of pressure gradient is used instead of dilysate.Blood pumping is carried through a dialyzer or hemoflter and water flows through a permeable membrane quickly facilitating dissolved substance move. A large molecular weight substances are removed mainly which are not cleared well with hemodialysis.lost salts and water are replaced in blood with substituting fluid that is infused into extracorporeal circuit during the treatment.


  • Diffusion & convection - Removal of extra water, salt, and waste, to prevent their building up in the body
  • Controls blood pressure up to some extent
  • Level of potassium, sodium and bicarbonate in blood is maintained


In some cases, acute kidney failure gets better after treatment so dialysis may be needed for a short time. If the kidney failure is of chronic type, then you have to carry dialysis for the rest of life time while the treatment is going on you may feel trouble. Special diet is required for both hemodialysis and peritoneal dialysis. It would be decided according to type of your dialysis. With the help of your doctor, you have to choose a correct method for you.


  • Removes the accumulated waste products, salt and extra water so that their levels may not increase in the body.
  • Keep a safe level of certain chemicals in the blood such as sodium, potassium and bicarbonate.
  • Helps control blood pressure.
  • Produces hormones that keep the bones strong.


  • Hemodialysis risks associated with placement of temporal vascular access (catheters).
    • Bleeding
    • Injury to neighboring structures such as artery, plura (cover of lungs) (causing accumulation of air in the cavity outside the lungs).
    • Infection
    • Accidental removal of catheter
    • Technical failure e.g. Blockage of catheter
  • Permanent catheter :
    • Technical failure e.g. Poor quality artery of vein
    • Infection
    • Bleeding
  • Complications from hemodialysis :
    • Fall of blood pressure
    • Cramps
    • Fever
    • Irregular heart beat
    • Other rarer complications include destruction of red blood cells (hemolysis) or lowering of oxygen in blood.
  • Peritoneal catheter :
    • Technical failure (displacement of catheter or block of catheter).
    • Infections
  • Procedure risks :
    • poor drainage
    • leak of fluid into chest or outside the peritoneal cavity
    • infections


Alternative to dialysis is Renal Transplant which may be advised to a patient depending upon various medical and other factors. At times the usual hemodialysis procedure may be substituted by another procedure which is carried out round the clock (CRRT) continuous renal replacement therapy.