A dialysis shunt is typically required to perform dialysis. This article explains exactly what a dialysis shunt is and how you can best care for it so that it lasts a long time.
Your kidney is a very important organ that performs many essential tasks. One of the most important tasks is the removal of waste products. These waste products are mainly created when the cells in your body produce energy. If, for some reason, your kidney is no longer able to sufficiently cleanse your blood of these waste products, another solution must be found. One such solution is dialysis.
There are several procedures to replace the tasks of your kidney. The most commonly used blood purification procedure to date is called hemodialysis. During hemodialysis, a your blood is purified outside your body in a machine called a dialyzer. But how does your blood get into the machine in the first place? Well that's a fair question.
What is a dialysis shunt?
There are several options for creating connections to your vascular system (=vascular access). Through a vascular access, blood can be removed from your body, purified externally, and returned back to your body.
The most frequently used vascular access in hemodialysis is called an AV fistula (=shunt). Since the dialyzer's job is to clean your entire blood volume, a fairly high blood flow in the corresponding blood vessel is needed - at least 300 milliliters per minute (mL/min). That's quite a lot.
As you probably know, your cardiovascular system is made up of two different types of vessels - arteries and veins. When doctors want to test your blood, the veins are punctured to take a blood sample. In the veins, the blood is transported to the heart with little pressure. On the other hand, the arteries represent the high-pressure system of the body. The heart pumps blood through the arteries at high pressure, to ensure that oxygen and nutrients are supplied to the entire body. Because the blood flow in your veins alone does not reach the 300 mL/min needed for dialysis, an alternative solution needs to be found.
A dialysis shunt is created by surgically connecting a vein and artery to one another - in other words, a short circuit is created between the low-pressure and high-pressure systems of the body. This also creates higher pressure in the corresponding vein. The higher the pressure, the more blood can be transported in the vessels per minute. In addition, the diameter of the vein expands due to the increased pressure - similar to when you inflate a balloon. This makes it easier to puncture the vessels and create access to your vascular system for dialysis. In addition, the larger diameter also allows for more blood flow.
Where is the shunt placed?
The most common location for a dialysis shunt is the forearm. Occasionally a shunt may be placed in the upper arm or even in the legs. To find a suitable site, your vessels are usually examined in advance with ultrasound. This way, the vessels with the best conditions can be selected.
What is the best way to care for my shunt?
Your shunt is essential for the performance of hemodialysis. To make sure it lasts extra long, you should take good care of it. Here are some useful tips:
1.Keep your shunt clean
You can prevent infections by regularly washing the shunt site with soap and water (for example, before each dialysis session). Before the dialyzer needles can be connected to the shunt for dialysis, the site must also be disinfected accordingly. After removing the needles, the area should be covered with a clean bandaid. This bandaid must be applied with sufficient pressure, otherwise bleeding may occur.
2. Check your shunt daily
Your dialysis team should regularly check the functionality of your shunt. However, you should also check your shunt on a daily basis. Since we often find it easier to develop a routine if we always do it at the same time, it is a good idea, for example, to briefly check your shunt every morning before or after brushing your teeth. To do this, it's best to always go through the same procedure.
Step 1: Look
Look closely at the area of your shunt and pay particular attention to any redness, swelling, bruising (=hematomas) and a clearly visible pulsation. Puffiness and swelling may indicate an infection. If your shunt pulsates clearly in one area, this can be an indication of a vessel bulge (=aneurysm). What exactly this is, you will learn below. In all these cases, you should contact your dialysis team.
Bruising often occurs when insufficient pressure has been applied to the shunt after the needles have been removed from it. Talk to your care team about this at your next dialysis appointment at the latest to avoid it as much as possible in the future.
Step 2: Feel
Placing your fingers lightly on your shunt will help you feel the blood flow. It's best to let your dialysis team show you exactly how to do this. If you cannot feel the blood flow, this is an indication of reduced blood flow in the area of the shunt or a complete blockage of your shunt. You should inform your treating physician as soon as possible.
At the same time, you should also pay attention to whether there is any pain when you palpate (=press) the site. This can also be an indication of an infection. If you experience pain, you should contact your dialysis team immediately.
Step 3: Listen
If you have a stethoscope, you can use it to listen to the blood flow in your shunt. But you'd probably rather leave that to the professionals on your dialysis team. A stethoscope is a medical examination device that is used to make body sounds, such as breathing, audible. For this purpose, it has a disc-shaped resonator to capture the sound. The resonator is connected to two earbuds via a tube. Your dialysis team can also use a stethoscope to check the blood flow in your shunt.
What should I avoid when I have a shunt?
To prevent blood flow from stalling in your shunt, blood pressure should not be taken on your shunt arm. A decrease in blood flow due to external pressure on the arm, such as would be the case during blood pressure measurement, can cause blood clots to form. These clots can then clog your shunt.
For the same reason, you should not wear any restrictive clothing, jewelry or watches on your shunt arm. You should also avoid carrying heavy shopping bags and lifting particularly heavy objects on your shunt side. In addition, do not allow anyone to insert an IV into your shunt (for example, to administer medication). This is an absolute no-go. Blood sampling should also - if possible - not be performed on the shunt arm. It gets irritated often enough.
Last but not least, try not to scratch around the shunt area. This can definitely be a challenge, as itching often occurs in people on dialysis. Scratching can cause sores that can become infected. Infected sores would mean that you wouldn't be able to use the shunt anymore, because there is a risk that the bacteria will get into your bloodstream. That can be very dangerous. Talk to your doctor early on if itching is a problem for you. There are several ways to reduce itching. If you want to know more about this topic, there are many more tips & tricks to reducing itching in the Mizu app.
How do I detect a problem with my shunt?
The direct connection between a vein and an artery is a great method to create a dialysis shunt. However, this connection is not natural so problems can occur from time to time. Below you can read about what problems can occur and how you can recognize them early on.
1. Bruising and swelling
In order to filter your blood during dialysis, the dialysis shunt must be punctured with two needles. The first needle takes blood from your body to the machine, and the second returns it to your body afterward. After dialysis, both needles are removed again. It is important to apply pressure to the punctured area after the needles are removed so that the hole in the vessel wall closes again quickly and blood does not leak into the surrounding tissue. However, sometimes blood still leaks into the surrounding tissue, which can cause swelling and bruising.
2. Redness and warmth
If your skin over your shunt is cracked and the skin there feels warmer than the surrounding areas, this may indicate the onset of an infection. In general, infections of the dialysis shunt are rather rare. However, if you notice any of these signs, contact your dialysis team immediately. They are the experts who can best advise you on how to proceed so that your shunt remains functional. Other symptoms of infection may include fever, pain, significant warmth in the area of the shunt, and swelling.
3. Aneurysm
The frequent puncturing and increased pressure in your shunt may cause the vessel wall in one area to become thinner and more easily stretched. This can cause a bulge in the vessel, also known as an aneurysm. Here, there is a greater risk of blood clots (=thrombi) forming, which can block your shunt. In addition, there is a risk that the inner vessel will eventually rupture and cause bleeding. If you see your shunt pulsating in one area, you should let your dialysis team know immediately as this could be an indication of an aneurysm
4. Decreased blood flow
In order for blood to be able to flow, there must be a high level of blood flow in your shunt vessel. Narrowing of your blood vessels (=stenoses) or blood clots (=thrombi) can reduce the blood flow in your shunt, which can have negative effects on your dialysis. With a little practice, you can learn to feel and check the blood flow yourself. Ask your dialysis team to show you how. They will also regularly keep an eye on the blood flow in your shunt.
5. Bleeding
It is very rare for heavy bleeding to occur from the shunt. However, if you experience heavy bleeding from your shunt at home - as if the needles have just been removed after dialysis - this is a medical emergency.
Apply pressure to the site of the bleeding with your other hand as soon as possible. Squeeze as hard as you can. Ideally, no more blood will flow past your fingers. If you have a sterile dressing handy, place it underneath. However, you should not waste time looking for it, because the first priority in this case is to stop the bleeding.
If there is someone near you, call for help and instruct that person to call an ambulance. If no one is around, call an ambulance yourself as soon as possible.
Also make sure that you lie down as quickly as possible. A large loss of blood can make you dizzy. If someone is with you, ask them to hold up your affected arm while either you or the other person continues to apply strong pressure to the bleeding area. By holding your arm up, you can get gravity to help you stop the bleeding. Try to stay calm, as hard as this may be.
This is what should be done in the case of heave bleeding but as mentioned before, such an emergency is very rare.
How is the shunt monitored?
As described, you can check your shunt independently every day. But your dialysis team will also keep an eye on your shunt.
In addition to visual inspection, listening and palpation, your blood flow in your shunt can be monitored by different procedures during dialysis.
If there is any suspicion that there are problems with your shunt, advanced tests will be performed. This may include an ultrasound examination of your shunt vessel. This test uses ultrasound waves to get an image of your vessel and blood flow.
Another option is X-ray imagine with the addition of a contrast medium. To do this, contrast material is injected into your blood vessels. This contrast agent is then visible on the X-ray image. Since it is in your vascular system, the entire volume of your vessel can be visualized and assessed. For example, the radiologist - the specialist in evaluating the X-ray images - can determine if there is a narrowing (=stenosis) in the area of the shunt.
How can complications be resolved?
Two of the most common complications of dialysis shunts are narrowing (=stenosis) and blood clots (=thrombosis), which can block the shunt. Both can cause the blood flow in your shunt to be reduced. Treatments exist for both.
If the problem is a narrowing (=stenosis) in the area of your shunt vessel, the site can be accessed via the vessel with a flexible tube (=catheter). A type of balloon can then be surgically inserted into the corresponding location. The narrowed section can then be widened by inflating the balloon.
If a blood clot is causing problems, it can either be dissolved by the targeted administration of medication - also via a catheter - or it can be mechanically crushed and removed.
As you see, a healthy shunt is extremely important for complication-free dialysis treatment. Make a habit of checking your shunt regularly and, if you notice any abnormalities, talk to your dialysis team immediately about any changes. After all, you know your body best!
