Kidney Failure and Dialysis

When kidneys fail, they cannot regulate water and ion levels or remove waste, such as urea. Kidney failure can be caused by several factors, including disease and physical injuries. If untreated, this can result in severe illness and even death. 

While mild kidney disease can be managed with medication, kidney failure requires more drastic interventions, such as dialysis or kidney transplants.

Kidney Dialysis is a treatment for kidney failure that acts as an artificial kidney, removing toxins and excess substances from the blood. During the process, unfiltered blood is taken from the body, filtered through a machine where it interacts with dialysis fluid, and then returned to the body. 

The dialysis fluid contains glucose and salts that mirror their normal levels in healthy blood. However, it does not contain any urea. Due to this composition, urea, which is usually high in the blood, naturally moves into the dialysis fluid. This is a process called diffusion. Similarly, glucose and salts also use diffusion to reach equilibrium.

Depending on their concentrations in the blood and dialysis fluid, they may move in either direction until the levels in both are balanced. As a result, harmful substances are removed from the blood and necessary substances are maintained, assisting the function that kidneys would normally perform.

How Dialysis Works

  • The dialysis fluid, which lacks urea, creates a significant concentration gradient. This causes urea to move from the blood, across a semi-permeable membrane, and into the dialysis fluid.
  • The dialysis fluid contains glucose at a concentration equivalent to normal blood sugar levels. This prevents any net movement of glucose as there’s no concentration gradient.
  • The salt concentration of the dialysis fluid mirrors the ideal concentration in the blood. This leads to salt movement across the membrane only when there’s an imbalance. If the blood’s salt concentration is too low, salts will move into the blood. If it’s too high, they’ll move out.
  • The machine continually refreshes the dialysis fluid. This maintains the concentration gradient between the fluid and the blood.
  • The dialysis process typically takes around 4 hours and needs to be performed multiple times a week. This prevents the harmful buildup of toxins in the body.
  • An anticoagulant is added to the blood before it enters the machine. This prevents blood clotting and ensures a smooth flow through the machine.

Advantages and Disadvantages of Dialysis


  • Dialysis performs the function of the kidneys when they are not able to do so. It removes waste and excess fluids from the blood, which makes it a life-saving treatment.
  • Dialysis can provide immediate relief from symptoms associated with kidney failure, such as nausea, swelling and fatigue.
  • Although dialysis requires a regular schedule, it can be conducted at a dialysis centre, at home or even while travelling, with the right equipment and planning. This makes it a flexible treatment method.
  • Dialysis can be used as a temporary solution until a kidney transplant becomes available or as a long-term treatment option when transplantation is not possible.


  • Dialysis often requires a significant time commitment. Each session typically lasts for several hours and multiple sessions are required per week.
  • Patients undergoing dialysis often need to follow strict dietary and fluid intake restrictions.
  • Regular dialysis can lead to a reduced quality of life due to its impact on daily activities, employment, travel and overall health. It can also cause emotional distress.
  • Dialysis is not a cure for kidney disease. It helps manage the condition but does not treat the underlying cause of kidney failure.

Kidney Transplant

The other option for treating kidney failure is a kidney transplant. This involves replacing the diseased kidney with a healthy one from a donor. However, the patient’s immune system may reject the donated kidney.

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