Before beginning hemodialysis treatment, a person needs an access to their bloodstream, called a "vascular access." The access allows the patient’s blood to travel to and from the dialysis machine at a large volume and high speed so that toxins, waste and extra fluid can be removed from the body.
Each access is created surgically. There are a limited number of places on the body where an access can be placed—the arms, legs, neck or chest.
The fistula and graft are considered to be permanent accesses because they are placed under the skin, with a plan to use them for many years. When patients find out they are in the advanced stages of chronic kidney disease and will be starting dialysis in the future, their nephrologist may advise them to get a fistula or graft. Having the access in place well before beginning dialysis will give this lifeline time to mature, so it will be ready to use when the time comes.
When patients suddenly discover they have kidney failure, a catheter may be placed to allow for immediate dialysis treatment. The catheter will be used until a fistula or graft has time to mature. A catheter can also be used on a permanent basis if a patient is unable to have a fistula or graft—but a catheter is always a last resort.
An AV fistula is created by directly connecting a person’s artery and vein—usually in the arm. As blood flows to the vein from the newly connected artery, the vein grows bigger and stronger. The patient is taught to do exercises—such as squeezing a rubber ball—to help the fistula strengthen and mature to get it ready for use. This usually takes anywhere from six weeks to four months. Once the fistula has matured, it can provide good blood flow for many years of hemodialysis.
Kidney and hemodialysis experts consider the fistula the "gold standard" access choice. Research studies have proven that patients with a fistula have the fewest complications, such as infection or clotting, compared to all other access choices.1
Some people may not be able to have a fistula due to weak arteries, veins or other medical conditions; it is best to discuss your access options with your doctor, but ask for a fistula first.
The AV graft is similar to a fistula in that it is also an under-the-skin connection of an artery and a vein, except that with a graft, man-made tubing connects the two. The soft, plastic-like tube is about a half inch in diameter and is made from a type of Teflon or Gore-Tex material. Transplanted animal or human vessels may also be used as grafts to connect an artery and vein. Grafts are usually placed in the arm, but can also be placed in the thigh.
Grafts do not require as much time to mature as fistulas because a graft does not need time to enlarge before use. In most cases a graft can be used about two to six weeks after placement. Because grafts are created from materials outside of the body, they tend to have more problems than fistulas due to clotting and infections. A graft may not last as long as a fistula and could need to be repaired or replaced each year.
Taking good care of your fistula or graft will help keep it working properly. There are a few things you can do to help prevent infections, clotting and damage to your access.
Keep your access area clean and free of any trauma. Look for signs of infection, including pain, tenderness, swelling or redness around your access area. Also, be aware of any fever or flu-like symptoms. If you do get an infection and catch it early, it can usually be treated with antibiotics.
Your dialysis care team will teach you how to carefully wash your access area before each dialysis treatment. Make sure to wash thoroughly and be sure the care-team member specially prepares your access site to prevent infection.
Protect your access from any restriction or trauma:
Learn the feel of the vibration of blood going through your access, and check it several times a day. Call your dialysis care team immediately if the flow stops or changes. This could mean a blood clot. With quick action, many clots can be dissolved or removed.
Learn to listen with a stethoscope to the sound (called bruit) of blood flowing ("whooshing") through your access. If the sound of the bruit changes to a higher pitch, like a whistle, it could be an indication that blood vessels are narrowing (called stenosis), which may slow or stop blood flow through your access. If you do not hear the bruit at all, or you hear only your pulse, you may have a blood clot in your access. Call your dialysis care team if you notice any change in your access.
To prevent tearing or damage to your access, pay attention to the needle-stick locations when you’re being put on dialysis. The arterial and venous needle tips should be at least two inches apart from each other, as well as away from access surgical scars. The new needle-stick sites should be at least one-fourth of an inch from the sites used the time before. Allow about two weeks for healing of previous sites to help maintain the health of the access.
Many people are nervous about having needles placed; however, numbing creams can be used to reduce the pain and fear of needle sticks. Talk to your nephrologist and your dialysis care team about ways to decrease pain and to calm anxiety.
After dialysis treatment your needles will be removed and you will need to apply pressure with sterile gauze over your needle sites to stop the bleeding. Your dialysis team will provide you with clean gloves and teach you the proper procedures to stop bleeding as well as prevent infection.
A catheter is a narrow tube that is placed into a large central vein, usually in the patient’s neck, chest or groin. Placement of the catheter usually takes less than half an hour. Usually two tubes extend out of the body from the catheter: one allows blood out of the body (arterial port) and one allows blood back into the body (venous port).
Catheters can be used for dialysis immediately after placement. A catheter may be used when one must begin dialysis before a fistula or graft has time to mature.
Some patients use permanent catheters. However, kidney and hemodialysis experts do not recommend catheters for long-term hemodialysis. Concerns with catheters include these:
Catheters require care to keep them protected, free of infections and working well.
It is very important to always keep your catheter exit site clean and dry. This may mean you cannot swim or take showers or soaking baths. You will need to carefully wash without getting your unhealed catheter exit site wet. Your physician may allow you to shower once your catheter exit site is well healed.
Your dialysis care team will teach you how to protect your catheter when it is not being used for dialysis. You will be taught the importance of making sure your catheter clamps are clamped and end caps are on securely when you’re not dialyzing. These will help decrease your risk of infection and prevent air from getting into your catheter. You will also be taught to check regularly for signs of infection, such as redness, swelling, pain, pus or fever. Call your dialysis care team right away if you think you may have an infection.
Your dialysis care team members will wash their hands and wear clean gloves when caring for your access.
Because your catheter exits and extends from your body, you’ll need to be careful not to pull on or tug it or the protective dressing. Be gentle around your catheter when getting dressed and undressed or removing a blanket or covering. Always keep sharp instruments, such as scissors, away from your catheter.
1. [Clin J Am Soc Nephrol. 2007 Jul;2(4):786-800. Epub 2007 May 30.]
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