Vascular Access and Cannulation Flashcards
6 cards from real CCHT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Vascular Access and Cannulation flashcards as text
What is the recommended needle gauge range for cannulating a mature arteriovenous fistula for standard hemodialysis?
Answer: 17–16 gauge
Standard AV fistula and graft cannulation for hemodialysis uses 15–17 gauge needles. The 16-gauge needle is most commonly used for blood flow rates of 300–400 mL/min, balancing adequate blood flow with minimizing vessel trauma.
What is the 'buttonhole' (constant site) cannulation technique, and what is its primary advantage?
Answer: Cannulating the fistula at the exact same sites each treatment to create a fibrous tunnel, allowing blunt needle entry and reducing pain and infiltration risk
The buttonhole technique involves inserting needles at the exact same angle, depth, and direction every treatment until a fibrous 'buttonhole' tunnel forms in the tissue. Once established, blunt needles can be inserted through the tunnel without penetrating new tissue, reducing pain and potentially decreasing infiltration and aneurysm risk.
During needle removal at the end of hemodialysis, a patient's AV fistula site bleeds continuously for 20 minutes despite applying pressure. What should the technician do?
Answer: Notify the nurse immediately while maintaining firm, focused pressure on the needle sites without completely occluding flow
Prolonged bleeding after needle removal requires immediate notification of the nurse while maintaining appropriate pressure. The key is to apply firm pressure to the needle sites specifically without completely occluding the fistula (which can cause thrombosis). A tourniquet would risk fistula thrombosis.
What is the 'rope-ladder' cannulation technique for AV fistula access?
Answer: Systematically rotating needle insertion sites along the entire usable length of the fistula with each treatment
The rope-ladder technique involves systematically rotating needle insertion sites up and down the entire length of the AV fistula with each treatment, like rungs on a ladder. This distributes trauma evenly along the fistula, preventing aneurysm formation at repeatedly punctured sites.
What are the signs and symptoms of arteriovenous fistula infiltration (extravasation) during hemodialysis?
Answer: Swelling, pain, and hardness at or near the needle site, often accompanied by a pressure alarm change
Infiltration occurs when the needle is displaced outside the vessel lumen and blood or saline infiltrates the surrounding tissue. Signs include sudden swelling (hematoma), pain and tenderness at the needle site, firmness of the tissue, and often a change in arterial or venous pressure alarms.
When inserting the arterial needle into an AV fistula for hemodialysis, in which direction should the needle bevel face and why?
Answer: Bevel up (facing away from the vessel wall) to facilitate entry into the lumen and optimal blood inflow
The needle bevel should face upward (away from the vessel wall) during insertion to facilitate smooth entry into the vessel lumen, reduce vessel wall trauma during insertion, and prevent the needle bevel from creating a flap valve against the vessel wall that would obstruct blood inflow.