DHA Cardiac Perfusionist exam questions

6 worked Cardiac Perfusionist practice questions

Original exam-style questions from the bank, spread across the blueprint domains. They are not real or recalled exam questions. Try each one, then open the answer for the rationale and reference. None of them appear in the free mock exam, so reading them will not spoil it.

1. Question 1 · Anticoagulation and Hemostasis

   A patient with acute heparin-induced thrombocytopenia needs urgent cardiac surgery that cannot be delayed. Which anticoagulant is recommended for CPB?

   1. AUnfractionated heparin
   2. BEnoxaparin
   3. CBivalirudin
   4. DWarfarin
   Show answer and explanation

   Correct answer: C. Bivalirudin

   When surgery cannot wait for antibodies to clear, bivalirudin is the preferred alternative anticoagulant for CPB in acute HIT. Any heparin exposure, including LMWH, can trigger thrombosis.

   Reference: ASH Guidelines for Heparin-Induced Thrombocytopenia 2018

2. Question 2 · CPB Circuit and Equipment

   During CPB, PaCO2 is 55 mmHg with adequate oxygenation. Which adjustment corrects this?

   1. AIncrease the FiO2 of the sweep gas
   2. BIncrease the sweep gas flow rate
   3. CDecrease the pump flow rate
   4. DDecrease the sweep gas flow rate
   Show answer and explanation

   Correct answer: B. Increase the sweep gas flow rate

   Carbon dioxide removal by a membrane oxygenator is controlled mainly by sweep gas flow; increasing it lowers PaCO2. FiO2 controls oxygenation and has little effect on CO2 elimination.

   Reference: Gravlee, Cardiopulmonary Bypass and Mechanical Support, 4th ed.

3. Question 3 · CPB Circuit and Equipment

   Which safety device stops or alarms the arterial pump when the venous reservoir volume falls below a set minimum?

   1. APressure relief valve
   2. BHeat exchanger
   3. CCardioplegia delivery set
   4. DLow-level sensor
   Show answer and explanation

   Correct answer: D. Low-level sensor

   The low-level sensor detects falling reservoir volume and alarms or stops the pump to prevent air being pumped to the patient. A pressure relief valve protects against over-pressurisation, not low volume.

   Reference: AmSECT Standards and Guidelines for Perfusion Practice

4. Question 4 · Mechanical Circulatory Support

   A patient on femoral VA-ECMO has recovering heart function but poor lung function. Right radial PaO2 is 50 mmHg while femoral arterial PaO2 is high. What is happening?

   1. ADifferential hypoxemia from native cardiac output
   2. BOxygenator failure within the ECMO circuit membrane
   3. CRecirculation of reinfused blood
   4. DArterial cannula dislodgement
   Show answer and explanation

   Correct answer: A. Differential hypoxemia from native cardiac output

   Native ejection of poorly oxygenated blood perfuses the upper body while ECMO blood reaches the lower body (north-south syndrome); right radial gases show the cerebral supply. Oxygenator failure would lower femoral PaO2 too.

   Reference: ELSO General Guidelines for Extracorporeal Life Support

5. Question 5 · Myocardial Protection

   A patient with severe aortic regurgitation is arrested for valve replacement. How should cardioplegia be delivered?

   1. AAntegrade into the aortic root at a higher flow
   2. BInto the right atrium only
   3. CRetrograde or directly into the coronary ostia
   4. DSystemic potassium without cross-clamp
   Show answer and explanation

   Correct answer: C. Retrograde or directly into the coronary ostia

   With a regurgitant aortic valve, root cardioplegia flows into the left ventricle, distending it and failing to perfuse the coronaries; retrograde or direct ostial delivery is used. Antegrade root delivery alone is ineffective.

   Reference: Gravlee, Cardiopulmonary Bypass and Mechanical Support, 4th ed.

6. Question 6 · Perfusion Emergencies and Safety

   Air is seen entering the arterial line during bypass. After stopping the pump and clamping the lines, which step helps clear air from the cerebral circulation?

   1. AHead-up tilt and rapid rewarming to 38 °C
   2. BRestart full flow at once, then de-air the circuit later
   3. CIncrease sweep gas flow to 10 L/min at once
   4. DHead-down tilt and retrograde perfusion via the SVC
   Show answer and explanation

   Correct answer: D. Head-down tilt and retrograde perfusion via the SVC

   Management includes stopping the pump, steep head-down position, de-airing the circuit and retrograde perfusion through the SVC to flush air from cerebral vessels. Restarting flow before de-airing would pump more air.

   Reference: Mills and Ochsner, J Thorac Cardiovasc Surg 1980