CCHT Vascular Access 3

Question 1

What is the buttonhole (constant site) cannulation technique, and what is its primary risk compared to the rope ladder method?

Accepted Answer

Inserting needles into the same track repeatedly to create a permanent blunt-needle cannulation site; risk is higher infection rate

Answer

Buttonhole cannulation creates a permanent subcutaneous track for blunt needle insertion, reducing cannulation pain, but carries a significantly higher infection risk than rope ladder.

Question 2

How should a dialysis technician respond if blood flow from a newly cannulated AVF immediately reads -250 mmHg arterial pressure at a blood pump speed of only 200 mL/min?

Accepted Answer

Reduce pump speed to 100 mL/min, assess needle position, check for needle in graft wall or positional issues, and notify the nurse

Answer

Excessively negative arterial pressure at low blood pump speed indicates a problem with blood delivery: needle malposition, kinked line, inadequate access, or access stenosis.

Question 3

What is a pseudoaneurysm (false aneurysm) of an arteriovenous fistula, and how does it differ from a true aneurysm?

Accepted Answer

Pseudoaneurysm is a pulsatile hematoma outside the vessel wall contained by fibrous tissue; true aneurysm involves all wall layers

Answer

A pseudoaneurysm results from a vessel wall defect with blood escaping into tissue and being contained by a fibrous capsule, not the actual vessel wall layers.

Question 4

What assessment finding during hemodialysis most strongly suggests that a patient's AVG has developed significant stenosis at the venous anastomosis?

Accepted Answer

Progressively increasing venous pressures over multiple treatments with reduced blood flow rates

Answer

Rising venous pressures over time indicate increasing outflow resistance, most commonly from stenosis at or near the venous anastomosis of an AVG.

Question 5

A patient with a forearm loop AVG has an area of thinned, shiny skin directly over the graft material. What is the clinical concern and appropriate action?

Accepted Answer

Risk of spontaneous graft rupture or erosion; do not cannulate the area and refer immediately to vascular surgery

Answer

Skin erosion or thinning over an AVG indicates the graft is eroding through the skin, a surgical emergency; the graft must not be cannulated and immediate surgical evaluation is required.

CCHT - Certified Clinical Hemodialysis Technician Practice Test

CCHT - Certified Clinical Hemodialysis Technician Practice Test

CCHT Vascular Access 3