Preparing for Dialysis
Dialysis is a way of cleaning the blood when the kidneys are no longer functional. Taking over the work of failing kidneys, a dialysis machine filters out toxins from the blood in people who have severe kidney disease.
Hemodialysis is a procedure where an external hemodialyzer (artificial kidney) is used to remove waste, extra chemicals, and excessive fluid from the blood. To gain access to a patient’s bloodstream, a vascular surgeon must perform minor surgery, usually in the arm or leg.
What to Expect with Hemodialysis
Prior to undergoing hemodialysis, patients need first to have a surgical procedure to prepare them for ongoing treatment. Preparation for hemodialysis ideally starts several weeks to months before dialysis is necessary. However, if the need for dialysis is urgent, there are options for access which can be used immediately.
To allow for easy access to the bloodstream, a surgeon will create a vascular access. The access provides a mechanism for blood to be safely removed from circulation, filtered, and then returned to the body.
There are several types of accesses that can be created for dialysis. These include arteriovenous (AV) fistulas, AV grafts, and hemodialysis catheters.
What Is an AV Fistula?
Normal veins are much too small to tolerate the large transfer of blood involved in dialysis. The preferred type of long-term access is an AV fistula. To create an AV fistula a vascular surgeon will surgically connect a vein to an artery, usually in the patient’s non-dominant arm.
After a fistula is created, it takes at least 6 weeks for the vein to grow to the size that is necessary for it to be successfully used for dialysis. During this time the vein grows wider and thicker, making it easier to place the needles for dialysis. The AV fistula also has a large diameter that allows the blood to flow out and back into the body quickly. The goal is to allow ample blood flow so that the largest amount of blood can pass through the dialyzer in the shortest amount of time.
The AV fistula is considered an ideal option because it:
- is less likely to become infected
- is less likely to clot
- tends to last longer
Typically the placement of an AV fistula is an outpatient procedure.
What Is a Graft?
Some patients are not good candidates for fistulas. A common reason for this is that the veins of the arm are too small in size to be used for a fistula. In this case, a graft may be the preferred option for access. A graft is usually placed in the arm but may be placed in the leg if necessary.
A graft is a synthetic piece of material sutured between an artery and a vein. One end of the tube is connected to an artery and the other end connected to a vein. This connection allows blood to flow from the high-pressure artery through the graft and into the low-flow, low-pressure vein. As a result, the blood flow through the graft provides a high enough flow rate for dialysis
Advantages of an AV graft include:
- Can be used in individuals with small veins
- Can be used shortly after placement for dialysis
A graft can be used in a shorter time frame. However, it comes with a higher risk of longer-term infection, and it tends not to stay open as long as an AV fistula. Regardless it is a good option for those who need it.
If an individual needs dialysis and does not already have a mature fistula, then it may be necessary to insert a catheter directly into a vein in the chest. The blood would then be drawn directly from this catheter for dialysis. Hemodialysis catheters are not considered a permanent form of access as they do come with increased risk for infection. However, they can provide an option for immediate dialysis.
Care of the Patient on Hemodialysis
At Vascular Specialists of Central Florida, we recognize that the transition to hemodialysis can be a stressful time for many patients and their families. We are here not only to surgically create an access but also to guide you through your options at this challenging time. Your access has been created we will continue to follow up with you to ensure that your access has the best chance of long-term success.
Our surgeons are highly skilled in the full spectrum of dialysis access intervention and care. Should you have any issues with your access at any point we are here to quickly address those issues so you are able to continue on with hemodialysis with as little interruption as possible.