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| Image Source: barwonvascular.com.au |
After completing this module, the learner will be able to:
• Describe the three main types of vascular access.
• Identify the predialysis assessments for all types of vascular access.
• Describe the methods of needle insertion forAVFs and grafts.
• Describe the predialysis assessment, accessing procedure, exit site care, and monitoring of catheters.
• Vascular access makes chronic hemodialysis possible because it allows the care team to "access" the
patient's blood.
• And access can be internal (inside the body) or external (outside the body).
It must:
• Allow repeat access to the blood
• Handle blood flow rates that will ensure effective treatments
• Be made of materials that are not prone to causing reactions or infections
The three main types of access are:
• Fistula
• Graft.
• Catheters
• To create a fistula, a surgeon sews an artery and a vein together, most often in the arm.
• Arteries carry oxygen-rich blood from the heart and lungs to the rest of the body.
• The vessels selected for a fistula are large and have good flow, but are deep below the skin and hard to reach with needles.
• Veins bring blood back to the heart and lungs; they are easy to reach, but too small and too slow flowing for dialysis.
• Linking an artery and a vein is the best of both worlds.
• In 4-6 weeks, high-pressure blood flow from the artery thickens the vein wall and makes it dilate (enlarge) so large needles can be used.
• Because a fistula is below the skin and is the patient's own tissues, it is less prone to infection and clotting
than other types of access.
• A fistula can last for years - even decades - and research shows it is the best type of access now available.
• To create a graft, a surgeon links an artery and vein with a piece of artificial blood vessel.
• Like a fistula, a graft allows access to the large volume of blood needed for dialysis.
• Grafts are more prone to stenosis (narrowing of blood vessels), which can cause thrombosis (blood clots).
• Grafts are also more prone to infection than fistulas, and have a shorter useful lifespan (less than 5 years on average)
• Grafts are an option for patients who do not have blood vessels suited to create a fistula.
• A catheter is a plastic, hollow tube placed in a deep central vein in the chest or leg.
• They allow short-term or long-term access to patient's blood.
• Deep central veins have a blood flow rate that allows adequate treatments.
• Catheters are made up of plastic that is foreign to the body, and they pass through the skin, creating a portal for bacteria.
• They are prone to stenosis, blood clots, and infection.
• Due to these problems, catheters must be replaced in the same or new vessels.
• Catheters are used for patients who:
• Can't have a fistula or graft
• Are waiting for a fistula or graft to be placed or to mature
• Have acute kidney failure and may soon recover kidney function
• Are waiting for a peritoneal dialysis catheter
• Are waiting for a live donor kidney transplant
• Access is still the one greatest challenge to the success of dialysis.
• Access problem frustrate the care team and the patient.
• Trouble cannulating (putting needles into) fistula and grafts is a source of stress for both.
• Poor cannulation can lead to problems that may cause access failure.
• Access failure means loss of the dialysis lifeline.
• The NKF KDOQI and the Fistula First program are two ongoing efforts to improve access outcomes
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