Renal Failure – Dialysis Access

Kidney or Renal Failure occurs when the kidneys stop filtering the blood of toxins and excess water build up. When untreated it is fatal. Dialysis is the treatment for this condition. This is a treatment for kidney failure where toxins from the blood are removed. There are two basic techniques, one is hemodialysis, where a machine is hooked up to the patient’s blood vessel; the other is peritoneal dialysis where a catheter is inserted into the patient’s stomach cavity followed by exchange of different fluids to remove the impurities. Hemodialysis may be performed through a fistula a graft or a catheter.

ARTERIO-VENOUS FISTULA

A small operation is performed usually under local anesthesia in the operating room. The procedure is usually done on an outpatient basis. The patient’s artery and vein are connected directly. It requires a good quality vein under the skin and good quality artery. The blood goes directly into the vein, the vein enlarges and its wall thickens. Once the vein has enlarged and thickened (matured) needles for the dialysis machine are inserted directly into the vein. Maturation can take from 6 weeks to several months. A fistula once mature can last for many years and thus it is regarded as the best long-term access for dialysis. The procedure carries a small risk of bleeding, infection, or decreased blood supply to the hands called steal syndrome.

ARTERIO-VENOUS GRAFT

A small operation is performed usually under local anesthesia in the operating room. The procedure is usually done on an outpatient basis. A plastic tube is inserted under the skin between the patient’s own artery and vein. This is done when the veins under the skin are too small for a fistula. It can be used for dialysis access earlier than a fistula (10-14 days) as it requires less time to develop. Grafts however, have a higher tendency to clot and stop working requiring further interventions. This occurs in most AV grafts at between 6 and 12 months and is most commonly caused by the development of scar tissue at the point where the graft and vein are connected. Procedures to declot these grafts are done under local anesthesia and not in the operating room. The procedure carries a small risk of bleeding, infection, or decreased blood supply to the hands called steal syndrome. There is also a small risk of infection of the plastic graft and this can require removal of the graft.

CATHETERS

A large intravenous catheter or cannula like device is inserted directly into the vein or through a tunnel under the skin into the vein. There are two basic types with multiple brand names. The simpler type can be done at the patients’ bedside with local anesthesia and involves inserting a large catheter through the skin directly into a large vein in the neck, upper chest or groin. It must be removed in approximately seven to ten days to prevent infection and a new access is thus then required. The other type of catheter is called a “perm-cath” as it is meant to be permanent- it rarely is. It is inserted via a small surgical procedure. The patient is given local anesthesia and sedation. A large catheter is inserted into the vein in the neck. However, it is then tunneled under the skin. This tunneling under the skin allows the catheter to be left in place for a longer period of time than the temporary catheter. These catheters also have a risk of becoming infected and they thus are not recommended as the ideal long-term method to facilitate hemodialysis. A catheter is easier to insert than the creation of a fistula or a graft, however, these catheter have a tendency to become infected and also they block off or clot. The procedure also carries a small risk of injury to the blood vessel and a small risk of collapse of the lung.