What is a Fistula? Why is this the Best Kidney Dialysis Access?
Posted Jul 28 2010 11:43pm
Dr. Aaronson recommends a fistula for dialysis access
In order to avoid infection, nephrologists recommend placement of a fistula in order to perform the kidney dialysis procedure. In the figure above, the red line represents an artery (oxygenated blood coming from the heart) and the blue line represents a vein (blood returning to the heart). In the patient above, a fistula has been created by a vascular surgeon
The fistula connects a bigger artery to a bigger vein so that the dialysis machine can pull more blood and dialyze (clean the blood of toxins and remove extra water weight) more quickly. The normal dialysis procedure takes from 3-4 hours, 3 times a week.
2 small needles are placed through the skin into the fistula: 1 in the arterial side, 1 in the venous side. The "dirty" blood goes to the dialysis machine, and the "clean" blood goes back into the patient.
As you can see in the figure, the patient is connected to the machine through 2 small needles. After the kidney dialysis procedure, the needles and the surgical tape are removed. The fistula is covered by the skin.
The alternative to a fistula is a permacath:
Kidney dialysis patient with a permacath in place.
A permacath is a catheter that is placed in the neck. The catheter is tunneled (if you look closely you can see the tunneling of the catheter traveling up to the neck). Tunneling allows for decreased risk of infection and a more cosmetically pleasing result than a big line sticking out of the neck -- but the risk for infection is still present. You can see the disadvantages of a permacath: bulky hardware, an external connection to the outside world (increases the risk for infection), and maintenance to keep the fistula clean.
Since it takes 6 weeks for a fistula to mature (be ready for use), kidney doctors like to get these placed early. If we run out of time, both a fistula and a permacath are placed by a vascular surgeon. When the fistula is ready for use, the permacath is pulled.
Please note: we use permacaths for aquapheresis, not fistulas. Its not safe to have needles coming out of the skin for extended periods of time. That's why we use the "central line." However, if your GFR is decreasing, your kidney specialist will likely recommend placement of a fistula to prepare for kidney dialysis.
Bottom line: fistulas take time to mature. Placement of a fistula does not mean that kidney dialysis is imminent. We are preparing for the future so that we can avoid a life-threatening dialysis emergency.