Vascular Access and Cannulation Basics Flashcards

What is an arteriovenous graft (AVG) made of, and what is its primary indication?

Answer: A synthetic tube (typically ePTFE) connecting an artery to a vein; used when native vessels are inadequate for AVF creation

AVGs use synthetic expanded polytetrafluoroethylene (ePTFE) or biological material to bridge an artery and vein when the patient's native vessels are too small or damaged for AVF creation. They mature faster (2–3 weeks) but have higher infection/thrombosis rates.

What does the term 'access recirculation' mean in hemodialysis, and how does it affect treatment?

Answer: A portion of dialyzed blood re-enters the arterial needle instead of returning to systemic circulation, diluting the blood being cleaned and reducing Kt/V

Access recirculation occurs when the venous and arterial needles are too close together or needle positions are reversed. Cleaned blood re-enters the arterial line, reducing effective blood flow and dialysis adequacy.

Which disinfectant is most commonly used to clean catheter hubs before accessing a hemodialysis catheter?

Answer: 70% isopropyl alcohol or chlorhexidine-alcohol scrub (15–30 seconds of friction)

Hub disinfection with 70% isopropyl alcohol or chlorhexidine-alcohol requires 15–30 seconds of mechanical scrubbing ('scrub the hub') before access. This is critical for preventing CRBSI in catheter-dependent patients.

A hemodialysis patient's fistula suddenly feels cold and the thrill is absent. What is the most likely diagnosis?

Answer: Acute thrombosis (clotting) of the fistula

Sudden loss of thrill with a cold, hard fistula indicates acute thrombosis. This is a vascular emergency requiring immediate notification of the care team and urgent referral for thrombectomy or thrombolysis.

Why is the arterial needle typically inserted in the direction of blood flow (toward the heart) in an AVF?

Answer: To allow the arterial needle to draw blood from the direction of highest flow for optimal pump function

For AVF, the arterial needle is typically placed antegrade (with flow, toward the heart) or retrograde depending on facility protocol and access anatomy. The goal is to separate arterial and venous needles by at least 3–5 cm to minimize recirculation.

What is 'steal syndrome' in a patient with an arteriovenous fistula?

Answer: The fistula diverts too much blood away from the distal hand, causing pain, numbness, or tissue ischemia

Steal syndrome (vascular steal) occurs when the high-flow fistula diverts blood away from the distal extremity. Symptoms include hand pain, coldness, numbness, and in severe cases, digital necrosis. It may require surgical intervention.