What is Dialysis?
Dialysis is a lifesaving procedure that replaces kidney function when organs fail. Before you can receive dialysis, doctors must connect the dialysis equipment to your bloodstream through one of several access options. Your nephrologist and surgeon will help you decide which type of access is best for you.
There are two types of dialysis:
Hemodialysis
Hemodialysis circulates blood through a machine outside of your body to remove toxins and excess fluid and to correct such electrolytes as potassium, sodium, phosphate, and calcium. The machine then pumps the cleansed blood back into your body. Your access options for hemodialysis are
- Catheter — a quick access solution if you need to begin dialysis immediately
- Fistula — a more permanent access solution
- Graft — another more permanent access solution
Peritoneal Dialysis
Peritoneal dialysis, an alternative to hemodialysis, doesn’t require access to the bloodstream. Instead, blood vessels in your abdominal lining (peritoneum) fill in for your kidneys, with the help of a fluid (dialysate) that flows in and out of the peritoneal space.
Before you can receive peritoneal dialysis, surgeons must place a long silicone-based tube, called a Tenckhoff catheter, into your abdomen. They position this tube deep into your lower peritoneal cavity (the membrane lining the inside of the abdomen) and then tunnel it under the skin several inches to an exit location.
Tunneling the catheter reduces the likelihood of infection in the peritoneal cavity. A sterile dressing will cover the catheter, which remains outside of the body.
You may be allowed to go home the same day of surgery, but you can’t begin peritoneal dialysis until the incisions heal — usually about two to four weeks after the access surgery.
Types of Catheters
What is a catheter and how is it placed?
Catheters are made from silicone tubing and placed in a large vein in the neck, chest, or leg. There are two types of catheters:
- Temporary catheters penetrate the skin and directly enter the venous (veins) system. Any medical professional can place a temporary catheter using a local anesthetic and minimal sedation to address minor discomfort. And for removal, they simply pull them out.
- Tunneled catheters, which also penetrate the skin, tunnel under the skin several inches before entering the venous system. Tunneling reduces the risk of infection. A surgeon or interventional radiologist must place a tunneled catheter to ensure it’s placed correctly. Removal requires a minor procedure by a medical professional.
Are catheters safe for long-term use?
No. Physicians make every effort to avoid prolonged catheter use because there’s a risk of infection. Bacteria can enter the bloodstream directly through the catheter during dialysis. Bacteria on the skin can also move down the catheter and enter the bloodstream. Patients with catheter infections develop high fevers and chills and need prompt treatment. Generally, physicians must remove the catheter so the body can fight the infection.
There is also a risk of damage to the main chest vessels. This can lead to stenosis (narrowing) or thrombosis (clotting) of the veins. This type of damage is usually permanent, and the vessel, as well as the arm on the side of the vessel, may no longer be useable for dialysis access.
Are there risks with the Tenckhoff catheter?
Yes. Although unusual, patients could experience such complications as bleeding and damage to the large or small intestines or abdominal blood vessels. These issues could require additional corrective surgery.
With peritoneal dialysis, there’s also a risk of peritonitis, an infection of the peritoneal cavity. Signs of peritonitis include abdominal pain, fever, and cloudy peritoneal dialysis solution. Doctors treat this infection with antibiotics. However, they might need to remove the catheter if antibiotics don’t eliminate the infection.
What is an AV fistula?
An arteriovenous (AV) fistula is an abnormal connection or passageway between an artery or a vein that enables blood flow. A fistula can be formed congenitally (naturally) or surgically to assist in dialysis.
An AV fistula is the best way to establish long-term access for hemodialysis. To create a fistula, a surgeon attaches a vein to an artery. This vein eventually grows larger and stronger, a process called maturation, and allows easy access for dialysis. It takes 6 to 12 weeks for the fistula to mature and be usable for dialysis.
The types of AV fistula available include:
- Radio-cephalic — formed by connecting the radial artery ((forearm) and cephalic vein
- Brachio-cephalic — formed by connecting the brachial artery (inner elbow area) and cephalic vein
- Transposition fistula — formed by connecting a mobilized vein from a deeper location to a superficial tunnel
Where are AV fistulas located and how long do they last?
Surgeons can create an AV fistula in your wrist, forearm, inner elbow, or upper arm. When properly constructed and after it’s matured, an AV fistula can function for many years.
Are there complication risks with the AV fistula procedure?
Yes, although rare, some patients may suffer such complications as:
- Infection
- Bleeding
- Arm swelling
- Tingling in the fingers
- Steal syndrome - when the arterial blood doesn’t reach the hand and causes ischemia (lack of oxygen). This condition requires a surgeon to establish a new access at a different site.
Can anyone have an AV fistula?
No. Numerous needle sticks for IV fluids, blood work, and medications can damage veins over time and create scar tissue, which makes creating an AV fistula impossible. If veins are too damaged or too small, an AV fistula will not mature or clot. In this situation, another course of action may be taken which may include another fistula at a different site, catheter, or arteriovenous graft.
What is an AV graft?
An arteriovenous (AV) graft is another form of dialysis access that can be used for patients without suitable veins for an AV fistula. To create an AV graft, a surgeon connects an artery and a large vein in your elbow or armpit using live tissue or synthetic material.
How is the AV graft procedure performed?
Surgeons connect the graft to a vein and tunnel it, just under the skin, to an artery where it’s attached. The tunnel gives the dialysis nurses space to access the graft.
How long do AV grafts last?
Grafts have a lifespan of approximately two to three years, but they can often last longer.
Are there complication risks with the AV graft procedure?
Yes, although rare, some patients may suffer such complications as:
- Bleeding
- Thrombosis (clotting)
- Infection - infected grafts require immediate removal. This condition requires a surgeon to establish a new access at a different site when the infection clears.
- Steal syndrome — when the arterial blood doesn’t reach the hand and causes ischemia (lack of oxygen). This condition requires a surgeon to establish a new access at a different site.
Compared with AV fistulas, AV grafts can be more troublesome because blood is more likely to clot in prosthetic material. When this happens, doctors must remove the clot and restore blood flow for dialysis.
When should I get dialysis access surgery?
The best approach is to undergo dialysis access surgery well before dialysis therapy needs to begin. This will give the access site time to mature, and you won’t have to use temporary catheters.
However, you may need a temporary catheter while you’re waiting for your permanent AV fistula or AV graft to mature or heal.
How will the dialysis access team determine what’s best for me?
The access team at Medical City Abdominal Transplant & Hepatobiliary Specialists will perform a thorough physical exam in addition to such tests as ultrasound and dye. These tests help us determine the appropriate type of access and identify the best site for access.