By Paul Kellerman, MD
As you all well know by personal experience, to effectively dialyze, one needs to ability to rapidly remove and return blood to a person via a vascular access. Currently, there are three potions to vascular access; tunneled catheters, arteriovenous (AV) grafts, and arteriovenous (AV) fistulas.
When a person needs to be started on dialysis urgently, they often have a tunneled catheter placed in their upper chest. Although the scar tissue in the skin tunnel makes a barrier to prevent bacteria from getting into the blood system around the catheter, bacteria still can travel on the inside of the catheter and often cause blood infections.
Patients often like these catheters because no needles are involved, but they have significant problems. First, they are the most likely access to result in a blood infection. Second, they often build up a "sheath" of clot around the end, and therefore have trouble achieving good blood flows. Last, one cannot bathe given the catheter comes through the skin. These catheters are not intended for long term use, but to bridge a patient over to an arteriovenous access.
There are two types of arteriovenous access, where an artery in the arm (or rarely groin) is bridge to a vein via a minor operation; the graft and the fistula, When a Dacron "bridge" is put between the artery and vein, this is called an AV graft. These can be used as early, often within two weeks or sooner, of placement. They are easy to stink for dialysis, because they are large and thick-walled. Common problems with AV grafts include clotting off the access, and infections. As you can see, infections occur much more often when there is a foreign substance (either the catheter or the Dacron graft) inside the body.
By far, the most preferred access is called an AV fistula. This is a direct connection between the artery and vein in the arm, with no foreign "bridge" between. The idea is for the arterial pressure to transmit into the vein, and therefore increase the size of the vein so it can be accessed for dialysis. These often take 4-6 weeks to develop. Although they take time to develop, fistulas have the greatest success, for they rarely clot and rarely get infected. People within our dialysis unit have had a single fistula form any years.
To give you an example of the benefits of a fistula, you are 11 time less likely to get an infection from a fistula than from a catheter. The professional kidney community wants every patient to have a fistula if possible, and the slogan for this movement is "Fistula First." The only limitation to having a fistula is scarring of veins in the arms. Our goal nation wide is to reduce our catheters in the dialysis unit to <10% of our patients, resulting in many less infections for patients.
If you have a catheter or an AV graft, please strongly consider the possibility of obtaining an AV fistula, for these are the best accesses for avoiding clots and infections and keeping you in the best of health for a long time. Speak to your primary nurse or physician about this option if you don't already have a fistula.
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