CHT Hemodialysis Technologist 3 — Questions and Answers
Question 1: Which dialyzer membrane characteristic determines its ability to remove middle molecules such as beta-2 microglobulin?
- Membrane thickness
- Ultrafiltration coefficient (Kuf)
- Flux (high-flux vs. low-flux) (Correct answer)
- Surface area only
Correct answer: Flux (high-flux vs. low-flux)
High-flux dialyzers have larger pore sizes that allow removal of middle molecules like beta-2 microglobulin, unlike low-flux membranes.
Question 2: A technician notices the conductivity alarm on the proportioning system is reading 16.5 mS/cm instead of the expected 14 mS/cm. The CORRECT action is to:
- Increase the dialysate flow rate to dilute it
- Take the machine out of service and notify the nurse (Correct answer)
- Continue treatment but document the deviation
- Add extra water concentrate to correct the reading
Correct answer: Take the machine out of service and notify the nurse
Conductivity outside the safe range indicates incorrect dialysate concentration, which is a patient safety emergency requiring immediate machine removal from service.
Question 3: Which anticoagulant is most commonly used during hemodialysis to prevent clotting in the extracorporeal circuit?
- Warfarin
- Aspirin
- Heparin (Correct answer)
- Enoxaparin
Correct answer: Heparin
Unfractionated heparin is the standard anticoagulant for hemodialysis due to its rapid action and reversibility with protamine sulfate.
Question 4: During hemodialysis, the transmembrane pressure (TMP) suddenly increases above the alarm limit. This MOST LIKELY indicates:
- Low blood flow rate
- Clotting in the dialyzer or venous line (Correct answer)
- Hypertension in the patient
- Excessive heparin administration
Correct answer: Clotting in the dialyzer or venous line
A sudden rise in TMP suggests clot formation increasing resistance to flow in the dialyzer or blood lines.
Question 5: What is the recommended minimum blood flow rate (Qb) for adequate hemodialysis in most adult patients?
- 50–100 mL/min
- 100–150 mL/min
- 200–400 mL/min (Correct answer)
- 450–600 mL/min
Correct answer: 200–400 mL/min
KDOQI guidelines recommend a blood flow rate of 200–400 mL/min to achieve adequate solute clearance during standard hemodialysis.
Question 6: Which condition is characterized by sudden confusion, headache, nausea, and seizures near the end of dialysis, caused by a shift in brain osmolality?
- Dialysis hypotension syndrome
- Disequilibrium syndrome (Correct answer)
- Air embolism
- First-use syndrome
Correct answer: Disequilibrium syndrome
Disequilibrium syndrome occurs when urea is removed faster from blood than from brain tissue, causing cerebral edema.
Question 7: A patient on hemodialysis has a serum potassium of 6.5 mEq/L pre-treatment. Which dialysate potassium concentration would be MOST appropriate?
- 4 mEq/L
- 3 mEq/L
- 2 mEq/L (Correct answer)
- 1 mEq/L
Correct answer: 2 mEq/L
A 2 mEq/L dialysate potassium creates a sufficient gradient to remove excess potassium in a hyperkalemic patient without causing dangerous hypokalemia.
CHT Hemodialysis Technologist 3
Which dialyzer membrane characteristic determines its ability to remove middle molecules such as beta-2 microglobulin?