Certified Hemodialysis Technologist/Technician Exam Dialysis Equipment and Troubleshooting 2 — Questions and Answers
Question 1: A blood leak alarm activates during dialysis. What is the first action the technician should take?
- Return blood to patient and disconnect
- Clamp blood lines and do NOT return blood to patient (Correct answer)
- Increase blood flow to confirm the alarm
- Check dialysate conductivity
Correct answer: Clamp blood lines and do NOT return blood to patient
When a blood leak is confirmed, blood lines must be clamped and blood should NOT be returned because the dialysate may be contaminated.
Question 2: Which factor most directly affects the efficiency of solute clearance in hemodialysis?
- Dialysate temperature
- Blood flow rate and dialysate flow rate (Correct answer)
- Patient's body weight
- Ultrafiltration volume
Correct answer: Blood flow rate and dialysate flow rate
Solute clearance is primarily determined by blood flow rate and dialysate flow rate, which drive diffusive transport across the membrane.
Question 3: What does the term 'high-flux dialysis' refer to?
- Use of very high blood flow rates above 500 mL/min
- Use of a dialyzer with a high KUF and ability to clear middle molecules (Correct answer)
- Dialysis performed more than 3 times per week
- Use of online hemodiafiltration only
Correct answer: Use of a dialyzer with a high KUF and ability to clear middle molecules
High-flux dialysis uses membranes with a high KUF and large pore size to remove middle molecules in addition to small solutes.
Question 4: What causes foaming in the venous drip chamber during hemodialysis?
- High blood flow rate
- Air in the arterial line causing turbulence (Correct answer)
- Hemolysis of red blood cells
- Low heparin dose
Correct answer: Air in the arterial line causing turbulence
Air entering the arterial bloodline creates turbulence in the venous drip chamber, resulting in foam formation.
Question 5: A patient's arterial pressure monitor reads increasingly negative values during treatment. What is the most likely cause?
- Access recirculation
- Venous needle kinking
- Inadequate blood flow from the access (Correct answer)
- Clotted dialyzer
Correct answer: Inadequate blood flow from the access
Increasingly negative arterial pressure indicates the blood pump is working harder to draw blood, usually due to poor flow from the vascular access.
Question 6: What is the function of the heparin pump on a dialysis machine?
- Flush the dialyzer with saline
- Deliver anticoagulant at a controlled rate into the arterial blood line (Correct answer)
- Monitor patient's clotting time
- Regulate ultrafiltration rate
Correct answer: Deliver anticoagulant at a controlled rate into the arterial blood line
The heparin pump infuses anticoagulant at a preset rate into the arterial blood line to prevent clotting in the extracorporeal circuit.
Certified Hemodialysis Technologist/Technician Exam Dialysis Equipment and Troubleshooting 2
A blood leak alarm activates during dialysis.
What is the first action the technician should take?