Hemodialysis

Hemodialysis is a process that removes toxins and excess fluids from a patient’s blood using a dialysis filter, known as a dialyzer, which acts as an artificial kidney. In hemodialysis, blood is pumped through the blood compartment of the dialyzer, which consists of hollow fibers with a semipermeable membrane containing thousands of tiny pores. Blood flows through these fibers while dialysis solution flows around the outside. This setup allows excess water and waste products to move from the blood into the dialysis solution. The cleansed blood is then returned to the body. Ultrafiltration, or the removal of excess body water, also occurs simultaneously, allowing 3-4 liters of fluid to be removed during a typical treatment.

Hemodialysis is usually performed three times a week, with each session lasting around four hours. Given that healthy kidneys work constantly 24/7 (168 hours per week), hemodialysis for 12 hours a week is minimal in comparison. To achieve highly effective dialysis, it’s crucial not only to have quality equipment and skilled technicians but also to ensure the water supplied to the machine is of the highest purity. During each session, a patient is exposed to an average of 120 liters of water, making water quality essential for safe and effective treatment.

When is Hemodialysis Needed?

Hemodialysis is commonly conducted in a hospital setting, within a dialysis unit. Most patients require hemodialysis three times a week, with each session lasting approximately four hours. Before starting hemodialysis, a surgical procedure is performed to create an access point in the body to connect blood to the hemodialyzer.

Typically, an Arteriovenous (AV) fistula is created by joining an artery to a vein under the skin in the arm to create a larger blood vessel. The AV fistula needs at least two months to mature before it can be used for dialysis.

If blood vessels are not suitable for an AV fistula, an AV graft — a synthetic tube made of PTFE — is used to connect an artery and a vein under the skin. This AV graft can be used by about ten days after placement.

In cases where immediate dialysis is required, a double-lumen catheter (a narrow plastic tube) may be inserted into a large vein in the neck as a temporary access. For those awaiting AV fistula or graft maturation, a cuffed catheter (Permacath) may be tunneled under the skin of the upper chest and connected to the neck vein. This type of access can be used for long-term dialysis treatment.