AVF Cannulation & Care Prof.Dr.Mohammed Abd Elbary Head of Nephrology & Transplantation Department Armed Forces Hospital, Alexandria

Hemodialysis HD is still the most common RRT modality in ESRD patients.

Hemodialysis Hemodialysis is a method used to achieve the extracorporeal removal of waste products such as creatinine and urea and free water from the blood when the kidneys are in a state of renal failure

Hemodialysis The first problem to be faced when choosing hemodialysis for ESRD patients is Vascular Access

Vascular access for patients on HD: Vascular access continues to be a leading cause for hospitalization and morbidity in patients with ESRD on HD. An ideal access must have the following criteria : Delivers a flow rate to the dialyzer adequate for the dialysis prescription. has a long use-life. has a low rate of complications (eg, infection, stenosis, thrombosis, aneurysm, and limb ischemia). Painless and available for use immediately upon placement. Eventually this ideal access is not yet available, but of the available accesses, the surgically created arteriovenous fistula (AVF) comes closest to fulfilling these criteria

Vascular access for patients on HD: There are three main forms of permanent HD vascular access: The arteriovenous fistula (AVF) The arteriovenous graft (AVG) Tunneled central venous catheter.

1- Tunneled catheters: The central venous catheter is popular because it is easy to place, may be used immediately, and is painless for the patient undergoing HD, as opposed to two needle sticks three times per week.

1- Tunneled catheters: Complications: Central venous stenosis, which can affect future vascular access attempts of any kind ( More than 40% of dialysis patients with access problems have been shown on venography to have a significant central venous stenosis). Infection is a very common complication associated with catheter use.

2- Arterio-venous grafts (AVGs): Grafts are created using either synthetic material usually polytetrafluoroethylene (PTFE, also known as Gortex), or bovine vessels between an artery and vein. For some practitioners, synthetic grafts are desired for ease of cannulation, shorter maturation times, and usefulness when a patient's vascular anatomy does not afford construction of an AVF. However, grafts have a higher infection rate, require more hospitalizations and procedures, and have a higher mortality rate than fistulas.

3- Native AVF: An AVF consists of a subcutaneous anastomosis of an artery to an adjacent vein. The anastomosis can be made either side of artery to side of vein or side of artery to end of vein. The most common AVF locations are radiocephalic (wrist), brachiocephalic (elbow), or brachiobasilic transposition.

3- Native AVF: The artificially induced high venous blood flow leads to the dilatation of the vein and to the thickening of its wall, providing a segment that can be punctured several times a week with a large gauge needle for performing HD. Usually the AVF take about 6 – 8 months for maturation and being ready for cannulation successfully

Complications of AVF: a) AVF steno-thrombotic complications: Venous stenosis Arterial stenosis AVF thrombosis: About 80–85% of arteriovenous (AV) access failures come from AV access thrombosis, more than 80% of which result from AVF stenosis. Decreased access flow is associated with an increased risk of access thrombosis. In addition to access flow, some mechanical factors influence AVF patency, such as the surgical skill, the puncture technique and various medical factors that may lead to AVF thrombosis

Complications of AVF: B)Aneurysms it generally affects the arterialized vein at the site of repeated venipuncture and may be generated by stenosis form chronic obstruction of proximal or central vessels. This leads to ulceration of overlying skin, cosmetic problems and increases risk of rupture of the AVF.

Complications of AVF: C)Infections of AVF: Infectious complications of AVFs are rare and generally affect sites of venipuncture. Individual predisposing factors include diabetes and immune deficiency states, together with lack of use of proper anti-sepsis procedures.

Complications of AVF: D)Steal syndrome : Steal syndrome is a term used to define a clinical picture characterized by ischemic symptoms of the limb where AVF is created, usually manifest by sensation of coldness and parasthesia of fingers accentuated during dialysis and improved by applying pressure to the AVF. In more severe cases nail lesion and ulcerations may develop.

AVF Cannulation

Risks Associated with Poor Cannulation & Improper Care of Fistula Loss of the fistula Further hospitalization Creation of temporary access measures Disruption of regular treatment regimen Higher treatment costs

Who Can Cannulate the AVF?

Common AVF Complication in Hemodialysis Unit

Prevent Cannulation Hematoma Prevent Post-Dialysis Hematoma Don’t flip needle Apply gauze without pressure Insert needle with 25 – 35º angle Remove needle at insertion angel Flush with Normal saline Apply gentle pressure with 2 fingers Hold pressure for average 10 min

Daily care of AV fistula (Patient Education)

The Do’s Reduce risk of infection by washing hands with soap and water both before and after touching AV fistula. Keep skin around fistula clean by washing it with antibacterial soap often, especially before dialysis. Clean the fistula by washing and gently patting it dry. After incision has healed, strengthen your arm by exercising it, as per by your doctor’s instructions. Check the pulse (thrill) in your AV fistula 3 times daily – morning, afternoon and evening by both listening to the AV fistula and by feeling it. Any change in sound should be reported to your doctor. Use your access for dialysis only. Look for redness or swelling around fistula area. Avoid injury to the arm and protect it. Ensure proper nutrition in order to keep your general health optimal.

The Don’ts Do not let anyone start an IV line or draw blood from AVF arm. Do not let anyone take blood pressure from AVF arm. Do not sleep on AVF arm. Do not carry heavy weights with AVF arm Do not wear a watch, bracelet or tight clothes over AVF Do not allow straps or handles tighten around the fistula, it is best to avoid carrying a purse or bag on that arm

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