Vascular Access for Hemodialysis
The two kidneys are bean-shaped organs, each about the size of your fist. They are located at the back of your abdomen, on either side of your spine. The kidneys work like a filter, getting rid of extra fluid and waste material in the blood. When your kidneys lose the ability to filter and clean the blood, the fluid and waste can build up and poison the body. This is called kidney (renal) failure.
When the kidneys can no longer clean the blood, dialysis may be needed. The most common form of dialysis is called hemodialysis. In hemodialysis, blood from an artery in your arm flows through a thin plastic tube to a machine called a dialyzer. The dialyzer filters the blood, working like an artificial kidney, to remove the extra fluids and waste from the blood. The cleaned blood then flows out of the machine through another tube placed into a nearby vein in the same arm. Most people have 3 dialysis sessions every week. Each session lasts about 3 or 4 hours.
What is a vascular access site?
Before you can begin hemodialysis, there needs to be a way to remove the blood from the body (a few ounces at a time) and then return it. Your arteries and veins are usually too small, so surgery is done to create a vascular access site.
There are 3 kinds of vascular access sites:
- A fistula (also called an arteriovenous fistula or A-V fistula) is made by joining an artery and a vein under the skin in your arm. When the artery and vein are joined, the pressure inside the vein increases, making the walls of the vein stronger. The stronger vein can then receive the needles used for hemodialysis. An A-V fistula usually takes 3 to 4 months to heal before it can be used for hemodialysis. The fistula can be used for many years.
- A graft (also called an arteriovenous graft or A-V graft) is made by joining an artery and vein in your arm with a plastic tube. The plastic tube is placed in a U-shaped loop under your skin, joining the radial artery to a vein near the elbow. The graft is usually ready to use about 3 weeks after the surgery. A-V grafts are usually not as long lasting as A-V fistulas, but a well-cared-for graft can last several years.
- A catheter is inserted into a vein in the neck or below the collarbone for short-term use until your A-V fistula or A-V graft is healed and ready to use. A catheter is not used for permanent access.
Certain tests help the doctors decide the best type of vascular access and the best location to put the access. The most common tests are venography and Doppler ultrasound. Your doctor will give you complete instructions to prepare for surgery.
The surgeon leads the surgical team, which includes other assisting surgeons, an anesthesiologist, and surgical nurses.
The surgeon creates the A-V fistula or the A-V graft in one of your arms. If you are right-handed, the fistula or graft will usually be placed in your left arm. If you are left-handed, the fistula or graft will usually be placed in your right arm.
You may use your arm as you normally do the same day as the procedure, but try to avoid heavy lifting.
If you had a catheter placed so you can have hemodialysis while your A-V fistula or graft is healing, you cannot get the catheter wet. An A-V fistula can get wet 24 to 48 hours after the procedure.
The A-V fistula procedure is an outpatient procedure, meaning you will not need to stay overnight in the hospital.
Patients who get an A-V graft will need to spend the night in the hospital for observation. Sometimes there is swelling or redness in the area where the graft is placed. The swelling will usually go away if you prop your arm on 1 or 2 pillows and keep your elbow straight and relaxed. Call your doctor if there are signs of severe redness or swelling, or if your arm becomes numb or weak.
Life After Vascular Access Surgery
Patients should avoid heavy lifting. Any injury to your arm can cause bleeding. When you go to the doctor, do not let anyone take your blood pressure, start an IV, or take blood from the arm with the A-V fistula or graft.
If you have an A-V graft, you should avoid wearing anything tight around your wrists or arms. Clothing or jewelry that is tight can decrease the blood flow in the graft, which can lead to blood clots within the graft. Also, do not lie or sleep on top of your arm.
You should always be able to feel blood rushing through your A-V graft. This feeling is called a thrill. You will also notice a slight vibration in the graft when you put your fingers on the skin over the graft.
See on other sites:
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Treatment Methods for Kidney Failure: Hemodialysis