Vascular Access
There are different types of vascular access
Temporary dialysis catheter
This is a Y shaped tube. One end is placed inside a large central vein and the
other end has two lumens which are used to connect to the dialyzer. Blood flows
out of the body through one lumen, circulates through the dialysis machine, and
flows back into the access through the other lumen. They can be done on the same
day and utilised immediately. But the main drawback of catheter is the risk
of infection. If not infected, it can be used for up to 8 weeks.
Tunnelled dialysis catheter (Permacath) This is almost like a temporary dialysis catheter
in that its end is inside a large central vein but then the other end is
tunnelled under the skin and opens upon the chest wall. A tunnelled catheter
is done on the same day and can be utilised immediately. Due to tunnelling
and presence of a cuff, infections are less common with tunnelled catheters.
If not infected, they can be used for up to a year.
Arteriovenous Fistula An arteriovenous fistula is created by making a
surgical connection between one of your arteries and one of your veins. Most
of the time, a fistula is created in your non-dominant arm, but it can also
be placed in your leg if the arteries and veins in your arm are not large enough
or healthy.
The AV fistula creation procedure is considered minor surgery
and is typically performed on an outpatient basis. The entire procedure usually
takes about one hour to complete.
After you’ve been mildly sedated, your
vascular specialist will use local anesthesia to numb the area in your arm or
leg where the fistula will be created. Next, a small incision will be made in
order to locate the vein and artery that will be used to create the fistula.
Once they are located, the vein will be connected to the artery and the skin
incision will be sutured closed.
AV fistulas need time to heal and mature
completely before they can be used as an access.
Who Can Get an Arteriovenous
Fistula?
An arteriovenous fistula requires daily inspection and
care. You need to clean it every day with soap and water, and you’ll want to avoid sleeping
on it. You need to look, listen and feel for signs that your AV fistula is functioning properly.
Look – Look at your access to check for signs of infection – swelling, redness, warmth
and drainage are all signs to watch for. Also note if there are any changes to the skin, such
as bleeding, bulging or peeling.
Listen – Put your ear to your arm (or leg) and listen
for the sound of blood flowing through your fistula.
Feel – Put your hand on your
access to feel the “thrill.” Any change in the feel of the vibration, or an absence of
vibration is cause for concern. If there is no vibration or thrill you should notify
your doctor immediately.
Advantages of an Arteriovenous Fistula
Your AV fistula will allow more blood to flow through your vein at a faster rate
and therefore an increase in the pressure within the vein. This increased venous
pressure stretches and strengthens the vein, allowing more blood to flow back and
forth from your vein to the dialyzer in a shorter amount of time.
There are
many advantages to an AV fistula, including: AV fistulas are created from
your body. There are no artificial components used.
a. They can function for
years.
b. They’re not as likely as a catheter to become infected or clotted.
c.
They are often easier to maintain than other access options.
d.AV fistulas provide
good blood flow to the dialyzer, often cutting down the time needed for treatment.
Disadvantages of an Arteriovenous Fistula
Like any of your options for
dialysis access, an arteriovenous fistula is not without their disadvantages. But these
drawbacks are fairly minor compared to the problems often associated with other access types,
such as a central venous catheter (CVC).iv The main disadvantages of having an AV fistula can
be:
a. If you need dialysis right away, you will need a temporary access that can be
used while your AV fistula is healing and maturing.
b. Healing can sometimes take longer
than expected, or the access may fail to mature.
c. Needles are required to access the AV
fistula for dialysis.
Needles are required to access the AV fistula for dialysis.