NCCT Hemodialysis Technician 2 — Questions and Answers
Question 1: What anticoagulant is most commonly used during hemodialysis to prevent clotting in the extracorporeal circuit?
- Warfarin
- Enoxaparin
- Heparin (Correct answer)
- Aspirin
Correct answer: Heparin
Unfractionated heparin is the standard anticoagulant for hemodialysis because it acts quickly, is reversible with protamine, and can be monitored at the bedside.
Question 2: Ultrafiltration in hemodialysis refers to:
- Filtering bacteria from the dialysate supply
- Sterilizing the dialyzer membrane between uses
- Increasing blood flow rate through the circuit
- Removal of excess fluid from the blood by a transmembrane pressure gradient (Correct answer)
Correct answer: Removal of excess fluid from the blood by a transmembrane pressure gradient
Ultrafiltration uses hydrostatic transmembrane pressure to drive excess water from the blood compartment across the dialyzer membrane into the dialysate compartment.
Question 3: A patient on hemodialysis develops muscle cramps mid-treatment. What is the most likely cause?
- Excessively high blood flow rate
- Dialysate temperature being too high
- Rapid fluid removal or electrolyte imbalance (Correct answer)
- Hypernatremia from the dialysate
Correct answer: Rapid fluid removal or electrolyte imbalance
Muscle cramps during dialysis are most commonly caused by aggressive ultrafiltration (rapid fluid removal) and associated electrolyte shifts, particularly in hypovolemic patients.
Question 4: The Kt/V measurement in hemodialysis is used to:
- Measure dialysate temperature regulation accuracy
- Calculate membrane permeability index
- Calibrate blood pump flow rate
- Quantify the adequacy of the dialysis treatment delivered (Correct answer)
Correct answer: Quantify the adequacy of the dialysis treatment delivered
Kt/V is the standard measure of dialysis adequacy, where K = dialyzer clearance, t = treatment time, and V = urea distribution volume; a minimum of 1.2 is recommended.
Question 5: Which laboratory value is most critical to check before starting a hemodialysis session?
- Hemoglobin A1c
- Serum potassium (Correct answer)
- Fasting blood glucose
- Prothrombin time
Correct answer: Serum potassium
Serum potassium must be assessed pre-dialysis because hyperkalemia can cause life-threatening cardiac arrhythmias, which dialysis is intended to correct.
Question 6: Which type of vascular access carries the highest risk of bloodstream infection in hemodialysis patients?
- Arteriovenous fistula
- Arteriovenous graft
- Central venous catheter (Correct answer)
- Subcutaneous port
Correct answer: Central venous catheter
Central venous catheters (CVCs) have the highest infection risk due to their direct access to the central vasculature and the presence of foreign material, making catheter-related bloodstream infections a leading cause of morbidity.
Question 7: When cannulating an AV fistula using the buttonhole technique, the hemodialysis technician:
- Rotates needle insertion sites with each treatment session
- Uses a progressively larger gauge needle each session
- Inserts needles at the exact same site and angle each session to create a fibrous tunnel (Correct answer)
- Places sharp needles randomly within the fistula segment
Correct answer: Inserts needles at the exact same site and angle each session to create a fibrous tunnel
The buttonhole technique requires consistent needle placement at identical sites and angles to form a scar tunnel, allowing blunt-tip needles to be used and reducing patient discomfort over time.
NCCT Hemodialysis Technician 2
What anticoagulant is most commonly used during hemodialysis to prevent clotting in the extracorporeal circuit?