What is dialysis access?
It is a way to your bloodstream lying just below your skin in the arm or the leg allowing blood to be removed and returned quickly, efficiently and safely during dialysis.
What is hemodialysis?
This is the most effective treatment for renal failure. The dialysis machine is an artificial kidney for removing impurities from your blood and return it quickly, safely and efficiently to your bloodstream. It thus regulates fluid and chemical balances.
What are the types of dialysis access?
This is a surgical procedure with the portal immediately below your skin.
- AV Fistula – the vascular surgeon joins the artery in your arm to the adjoining vein
- AV Graft – A synthetic tube is placed below the skin connecting the artery to the vein.
In both the cases blood flows from the artery to the vein, dilating it and also strengthing it. By this procedure, a large amount of blood passes through the vein rapidly which helps dialysis to proceed efficiently.
The fistula takes about 8 – 12 weeks to mature. At maturity, a large dialysis needle can be placed within the vein without injuring it.
AV Graft may be used for dialysis within 2 – 6 weeks.
Normally fistulas are preferred as there are lesser chances of infection and grafts are the last resort.
How do you select patients for AV Fistulas?
- There should be no arterial insufficiency. A weak pulse means a narrow artery which would reduce the blood flow causing the fistula to fail.
- The arm is a preferred site because there are more chances for arteriosclerosis in the leg.
- A color Doppler study is done prior to surgery to make sure that the arterial blood flow is adequate. The vein is viewed to see its size and any blockages.
- Fistulas are mostly done under local anesthesia. The patient does not need to be starved and regular medication can be taken.
Am I eligible for dialysis access?
- If one has chronic renal failure and needs long term dialysis then access is advised.
- Fistulas are avoided if veins are narrowed or scarred from previous line placement or the arteries are blocked.
- If AV Fistula is not feasible then AV Grafting is recommended.
- Grafts are avoided if there is an ongoing infection. In the unfortunate occurrence of infection, the grafts must be removed otherwise infection can never be brought under control and the patient could become very sick and septic.
How is AV Fistula or Graft done?
- This is preferably done under local anesthesia unless the patient is very anxious when sedation is given.
- It is constructed using a single incision at the wrist or the elbow. (picture 3)
- The vein is divided and attached to the artery nearby. Some of the blood flowing down the artery to the hand is directed into the vein. Despite the flow of blood in the vein, the flow to the hand is adequate
If the vein is thin and of poor quality or blocked then a synthetic graft is placed between an artery and vein. It is placed as a loop just below the skin in the arm or the forearm and rarely in the leg.