Vascular Access for Hemodialysis (HD)

Overview

The kidneys conduct vital tasks that keep life going. They clean the blood on a constant basis, clearing away contaminants and harmonizing body chemistry. They also aid in the regulation of blood pressure and the amount of fluid exiting the body.

If the kidneys fail, either at the end stage of chronic kidney disease (referred to as end stage renal disease or ESRD) or as a result of an acute kidney injury, there are two options to take over the work of the non-functioning kidneys: dialysis, a group of alternatives to cleanse the blood outside of the kidneys, or transplantation of a healthy kidney into the body.

Adequate patient preparation for hemodialysis requires the timely development of an AV fistula. In compared to other vascular access types, an AV fistula is the most acceptable kind of vascular access for hemodialysis.

 

What is a Vascular Access?

A vascular access is a hemodialysis patient's lifeline since it allows them to get life-saving hemodialysis treatments. Hemodialysis is a kidney failure therapy in which a machine sends the patient's blood through a filter called a dialyzer outside the body. During hemodialysis, the access is a surgically constructed vein that is used to extract and return blood. A few ounces of blood are drawn by a needle at a time. The blood is then sent through a tube to the dialyzer.

Blood travels through fine fibers inside the dialyzer, filtering away wastes and superfluous fluid. The filtered blood is returned to the body via a separate tube by the machine. During hemodialysis treatments, a vascular access allows huge quantities of blood to flow continuously in order to filter as much blood as possible each session. Every minute, around a pint of blood runs through the machine. A vascular access should be established several weeks or months before the first hemodialysis session.

 

4 Types of Dialysis Access

There are three different types of dialysis access used for hemodialysis, a process in which blood is transported from your body for cleaning.

• Central venous catheter (CVC)
• Arteriovenous fistula (AV Fistula)
• Arteriovenous graft (AV Graft)

A different sort of access is required for peritoneal dialysis, which uses the abdominal lining and a particular sterile solution to clean the blood within your body.

• Peritoneal dialysis catheter (PD Catheter)

Many variables will influence which access is ideal for you. Let's take a look at each form of dialysis access individually.

 

Central Venous Catheter (CVC)

A central venous catheter (CVC) is a flexible, long, plastic, y-shaped tube that is inserted through your skin into a major vein in your neck, chest, or groin. A CVC is often not meant to be a permanent form of access. If you require immediate or emergency dialysis, are unable to obtain it, and do not have an AV fistula or graft, you will need a CVC.

 

Caring for your catheter

Your doctor will write you a prescription for the items you'll need to keep your catheter clean. These are available at any drugstore or medical supply store. To look after your catheter, do the following:

• Before touching any portion of your catheter or catheter incision, wash your hands (the area on your skin where the catheter goes into your body).
• Use a sponge and cleaning solution to keep the area surrounding the catheter incision clean at all times.
• Keep the dressing over your catheter incision clean and dry, and change it as directed by your doctor, or if it becomes moist, filthy, or loose. Make sure you have a sufficient supply of dressing supplies at home in case you need to replace it.
• Keep the area surrounding the catheter incision dry. Inquire with your nurse or doctor about bathing with a catheter, such as wearing a particular protective cover when showering.

Take care of it

• Keep the clamps on your catheter tubes closed unless the catheter is being used.
• Flush (rinse out) the catheter as often as your doctor tells you to.

Check it every day

• Look for signs of infection, such as:

• Pain
• Redness
• Swelling
• Discharge (oozing) from the incision
• Fever
• If you have any of these symptoms, call your doctor right away.

 

What is an Arteriovenous Fistula?

An AV fistula is a vascular surgeon-created link between an artery and a vein. Arteries transport blood from the heart to the body, whereas veins transport blood from the body to the heart. Vascular surgeons do blood vessel surgery. An AV fistula is often placed in the forearm or upper arm by the surgeon. An AV fistula promotes increased pressure and blood flow into the vein, causing it to grow big and powerful.

The bigger vein allows for simple and consistent access to blood vessels. Regular hemodialysis treatments would be impossible without this type of access. Untreated veins cannot sustain several needle insertions because they collapse like a straw under severe suction.

Health care providers recommend an AV fistula over the other types of access because it

• Provides good blood flow for dialysis.
• Lasts longer than other types of access.
• Is less likely to get infected or cause blood clots than other types of access.

A vascular mapping test may be performed by the surgeon prior to AV fistula surgery. Vessel mapping use Doppler ultrasonography to analyze blood vessels that may be used by the surgeon to create the AV fistula. Ultrasound creates a picture of organ anatomy by using a device called a transducer, which bounces safe, painless sound waves off organs. The procedure is carried done at a health care provider's office, an outpatient clinic, or a hospital by a properly trained technician.

The photos are interpreted by a radiologist, a doctor who specializes in medical imaging. This treatment does not require the patient to be sedated. A Doppler ultrasound determines how much and how rapidly blood flows through arteries and veins, allowing the surgeon to choose the optimal blood vessels.

In an outpatient clinic or a hospital, a surgeon conducts AV fistula surgery. Although the vascular access operation may need an overnight stay in the hospital, many patients are discharged the same day. Local anesthetic is used by a health care practitioner to numb the region where the AV fistula is created by the surgeon.

Before a patient may use an AV fistula for hemodialysis, it usually takes 2 to 3 months to grow or mature. If an AV fistula fails to form after surgery, the treatment must be repeated.

A health care practitioner or the patient inserts two needles into the vascular access at the commencement of a hemodialysis session. A single needle transports blood from the body to the dialyzer. The other returns filtered blood to the body. To distinguish between the needles, the arterial needle is the one that transports blood away from the body. The venous needle is the needle that returns blood to the body.

Some patients choose to insert their own needles into the vascular access, which necessitates instruction in infection prevention and vascular access protection. Regardless of who inserts the needles, the patient should understand how to care for the needle insertion location to avoid infection.

If an AV fistula does not develop, an AV graft is the next best option for long-term vascular access.

 

What is an Arteriovenous Graft?

An AV graft is a plastic tube with loops that joins an artery to a vein. In an outpatient clinic or a hospital, a vascular surgeon conducts AV graft surgery, similar to AV fistula surgery. As with AV fistula surgery, the patient may need to stay in the hospital overnight, however many patients are able to go home after the treatment. Local anesthetic is used by a health care professional to numb the region where the AV graft is created by the surgeon.

An AV graft may normally be used 2 to 3 weeks following surgery. An AV graft is more prone than an AV fistula to develop infection and clotting issues. Repeated blood clots might obstruct blood flow through the transplant. A well-cared-for graft, on the other hand, can survive for years.

 

How a Fistula or Graft Looks and Feels

An AV graft may normally be used 2 to 3 weeks following surgery. An AV graft is more prone than an AV fistula to develop infection and clotting issues. Repeated blood clots might obstruct blood flow through the transplant. A well-cared-for graft, on the other hand, can survive for years.

A fistula is a big vein that causes a scar on your arm. This is typical and indicative of a strong, healthy lifeline. However, people may notice it and inquire about it. The needle marks can also be seen. It may also take some time to adjust to the buzzing of a healthy access. A graft is smaller, yet it might seem as a huge line or loop under your skin.

To conceal a fistula or graft, some people wear long sleeves all year. Others see their access as a battle scar from a battle they are winning with renal failure. After all, we are all scarred. Some people use queries about their access as an opportunity to teach others. It may help you cope with the shift in your body if you anticipate queries and prepare responses. It is normal to be unhappy about physical changes. It can also help you talk about your feelings. Your fellow dialysis patients understand what you're going through.

 

Set Up the Vascular Access Well before Starting Hemodialysis

Patients should establish vascular access prior to beginning hemodialysis since AV fistulas and AV grafts both require time to develop before they can be used. Even if the patient is feeling great, a health care practitioner can assist in scheduling an appointment with a vascular surgeon long before the patient begins hemodialysis. Allowing vascular access to mature can help avoid small veins, limited blood flow, and blood clots.

To preserve the blood arteries in the arm, health care practitioners should collect blood from the back of the patient's hand before to the surgery. A doctor can educate the patient basic activities that will assist the blood vessels grow larger for the surgeon to employ. The same movements aid in the recovery of the AV fistula.

 

What is a Venous Catheter?

A venous catheter is a tube that is placed into a vein in the neck, chest, or leg near the groin to provide hemodialysis for a brief period of time. After leaving the body, the tube divides in two. The two tubes have caps that attach to the lines that carry blood to the dialyzer and blood from the dialyzer back to the body. When attaching and detaching the catheter from the tubes, the clamps on each line must be closed If a patient's renal disease has advanced rapidly, he or she may not have enough time to have an AV fistula or AV graft placed before beginning hemodialysis treatments.

The venous catheter placement technique is performed in a hospital or an outpatient clinic by a nephrologist (a doctor who specializes in kidney diseases) or an interventional radiologist (a doctor who utilizes medical imaging technology to do surgeries). To remain calm and peaceful during the treatment, the patient is given local anaesthetic and sedative.

Long-term usage of venous catheters is not recommended. A venous catheter can cause a blood clot, infection, or scarred vein, leading the vein to shrink. If a patient requires hemodialysis immediately away, a venous catheter will suffice for several weeks or months until a surgeon can conduct long-term access surgery and the AV fistula or AV graft has had time to grow.

If fistula or graft surgery fails, the patient will require long-term venous catheter access. When a venous catheter is required for more than three weeks, the surgeon will "tunnel" the catheter under the skin rather than inserting it directly into the vein. A tunneled catheter is more comfortable and less likely to cause complications. However, even tunneled catheters can get contaminated.

 

What to Expect When a Catheter is Placed?

If you require HD right away, you will require an HD catheter. You will also require one if you have a fistula or graft that has to be repaired. Any HD patient may require a catheter at some time.

It takes 15 to 30 minutes to insert an HD catheter. It is possible to employ an operating room or a radiology suite. You will be awake, but you should take medication to relax and relieve discomfort. A trocar will be used to create a tunnel beneath your skin. The catheter is then introduced through a wire. The cable has been removed. Then you'll need a chest X-ray to make sure it's in the appropriate place.

Stitches will be used to keep a "temporary" HD catheter in place. These can pull and cause discomfort. Plastic cuffs are placed beneath your skin via a "Permcath." To keep the cuffs in place, your tissue grows into them. But don't be fooled by the name! Unless you have no other choices, HD catheters should only be used for a limited period of time.

Before you leave, be sure you know:

• How to change the dressing if it falls off or gets wet. Never use scissors near an HD catheter.
• How to clamp the catheter if it starts to bleed.
• What to do if the catheter falls out or is pulled out by mistake.

To care for a new catheter, do these things each day:

• Look for redness, swelling, or pus that could mean an infection.
• Keep your catheter dry. No swimming. No showers unless you use a special cover.

 

Long-term Fistula or Graft Problems

All three kinds of vascular access—AV fistula, AV graft, and venous catheter—can result in complications that need further therapy or surgery. The most prevalent issues are access infection and decreased blood flow as a result of blood clotting in the access.

Infection and decreased blood flow are less common in correctly constructed AV fistulas compared to AV grafts and venous catheters. Having an AV fistula, however, does not ensure trouble-free entry.

Low blood flow is more common with AV grafts, indicating clotting or access constriction. The AV graft may then require angioplasty, which is a technique to enlarge the tight section. Another approach is to replace the narrow section of the AV graft with surgery.

Venous catheters are the most prone to infection and clotting issues. If these issues arise, medicines may be of assistance. Antibiotics are drugs that are used to combat germs that might cause illness. Warfarin and other blood thinners prevent clotting. If these therapies fail, the catheter will need to be replaced by a nephrologist or an interventional radiologist.

 

Conclusion 

Acute kidney failure (AKF) and chronic kidney failure (CKF) patients require suitable vascular access for hemodialysis. Hemodialysis (HD) removes wastes and water from your blood. Vascular access is your lifeline on HD. Access is a method of cleaning your blood.