Before hemodialysis can be done, a way for blood to leave and return to your body (an access) is needed. During hemodialysis, needles placed into the access carry blood to and from the dialyzer. A hemodialysis access is usually created in your arm. The 2 main types of accesses are an arteriovenous fistula (AV fistula) and an arteriovenous graft (AV graft).
The hemodialysis access provides a large volume of rapidly flowing blood. It involves a surgical operation under anesthesia. You may be able to go home the same day. It is made during a short procedure using one of these methods:
A fistula is made by connecting an artery to a nearby vein. The high pressure and blood flow in the artery are transferred into the vein and help it grow in size and thickness. This enlarged vein (fistula) eventually has high blood flow and is thick enough for needles to be placed safely several times each week during hemodialysis. It may need weeks or months to develop before it's ready to be used. A fistula is more efficient than the graft and has fewer long-term problems. Therefore, it is the preferred form of access.
A graft (piece of synthetic tube) may be sewn between an artery and a vein if a fistula is not possible because of the small size of your veins. Blood flows rapidly through the graft from the artery to the vein. A graft is usually ready to use in a few weeks. Needles can be placed into the plastic tube to obtain blood during dialysis.
Both types of access may take weeks to months before they can be used. If dialysis is necessary immediately, a temporary venous catheter is used. A catheter that allows two way blood flow is placed into a large vein and the dialysis tubing is connected to the catheter. If both the AV fistula and graft are unsuccessful, a more permanent venous catheter is used.
The most common complications for hemodialysis access are infection, clotting and decreased blood flow from clotting or other narrowing.
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