Certified Hemodialysis Technologist/Technician Exam Vascular Access and Cannulation 2 — Questions and Answers
Question 1: What minimum needle gauge is required to achieve blood flow rates of 400-500 mL/min during hemodialysis?
- 25 gauge
- 21 gauge
- 16-17 gauge (Correct answer)
- 14 gauge only
Correct answer: 16-17 gauge
16-17 gauge needles are standard for hemodialysis to allow blood flow rates of 300-500 mL/min without excessive hemolysis or pressure.
Question 2: When assessing a newly placed AV graft, how long should the technician typically wait before the first cannulation?
- 24 hours
- 48-72 hours
- 2-3 weeks (Correct answer)
- 6 months
Correct answer: 2-3 weeks
AV grafts typically require 2-3 weeks of healing before first cannulation to allow incorporation and reduce risk of hematoma or infection.
Question 3: Dialysis steal syndrome occurs when:
- Too much blood flows through the access, reducing distal limb perfusion (Correct answer)
- The access clots repeatedly
- The patient experiences hypotension
- Venous pressures exceed 250 mmHg
Correct answer: Too much blood flows through the access, reducing distal limb perfusion
Steal syndrome occurs when arterial blood is diverted preferentially into the AVF/graft, reducing perfusion to the hand and causing ischemia.
Question 4: After removing hemodialysis needles, how long should manual pressure typically be held to achieve hemostasis on an AVF?
- 30 seconds
- 1-2 minutes
- 5-15 minutes (Correct answer)
- 30 minutes minimum
Correct answer: 5-15 minutes
Manual pressure of 5-15 minutes is typically required after needle removal from an AVF to achieve adequate hemostasis without compromising the access.
Question 5: Which finding on physical examination of a central venous catheter (CVC) exit site requires immediate intervention?
- Dry, intact healing around the cuff
- Purulent drainage, redness, and warmth at exit site (Correct answer)
- Slight scabbing at the exit site
- Clear serous fluid at exit site day 1 post-insertion
Correct answer: Purulent drainage, redness, and warmth at exit site
Purulent drainage with redness and warmth at a CVC exit site indicates infection requiring immediate evaluation, culture, and likely catheter removal.
Question 6: The 'rope ladder' technique of AVF cannulation involves:
- Using the same holes each treatment
- Rotating needle sites along the entire length of the fistula (Correct answer)
- Only cannulating near the anastomosis
- Using two needles on the same segment
Correct answer: Rotating needle sites along the entire length of the fistula
The rope ladder technique distributes needle insertions evenly along the entire fistula length, preventing aneurysm formation at any single site.
Certified Hemodialysis Technologist/Technician Exam Vascular Access and Cannulation 2
What minimum needle gauge is required to achieve blood flow rates of 400-500 mL/min during hemodialysis?