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Question 1. Which chamber of the heart receives oxygen-rich blood from the pulmonary veins? A) Right atrium B) Right ventricle C) Left atrium D) Left ventricle Answer: C Explanation: The left atrium is the entry point for oxygenated pulmonary venous blood before it passes through the mitral valve to the left ventricle. Question 2. In the pressure-volume loop, the vertical segment on the left side of the loop represents which phase of the cardiac cycle? A) Isovolumetric contraction B) Ejection C) Isovolumetric relaxation D) Rapid filling Answer: A Explanation: During isovolumetric contraction, ventricular pressure rises while volume remains constant, creating the left-most vertical line. Question 3. The primary purpose of the ductus arteriosus in fetal circulation is to: A) Supply the lungs with blood B) Bypass the non-functional fetal lungs C) Return oxygenated blood to the placenta D) Provide a route for umbilical venous blood to the right atrium Answer: B
Explanation: The ductus arteriosus shunts blood from the pulmonary artery to the aorta, bypassing the fluid-filled fetal lungs. Question 4. Which of the following best describes the shape of the oxyhemoglobin dissociation curve? A) Linear B) Hyperbolic C) Sigmoidal D) Exponential Answer: C Explanation: Hemoglobin’s cooperative binding produces a sigmoidal (S-shaped) curve. Question 5. In a membrane oxygenator, gas exchange occurs primarily by: A) Direct diffusion through a porous matrix B) Bubble formation within the blood stream C) Diffusion across a thin, gas-impermeable membrane D) Liquid-liquid extraction Answer: C Explanation: Membrane oxygenators separate blood and gas phases with a thin, selectively permeable membrane, allowing diffusion without direct contact. Question 6. A V/Q mismatch that predominantly lowers arterial oxygen tension during ECMO is most likely caused by: A) Low pump flow B) High sweep gas flow C) Inadequate membrane surface area
C) Idarucizumab D) Andexanet alfa Answer: B Explanation: Protamine binds to heparin, neutralizing its anticoagulant activity. Question 10. Which anesthetic adjunct is most commonly used for muscle relaxation during bypass? A) Propofol B) Midazolam C) Rocuronium D) Dexmedetomidine Answer: C Explanation: Rocuronium is a non-depolarizing neuromuscular blocker with rapid onset and predictable duration. Question 11. Compared with roller pumps, centrifugal pumps are associated with: A) Higher risk of hemolysis B) Greater afterload sensitivity C) Lower priming volume D) More consistent flow independent of preload Answer: D Explanation: Centrifugal pumps generate flow based on rotor speed and are less dependent on inlet pressure, reducing afterload sensitivity. Question 12. The main function of the arterial filter in the CPB circuit is to: A) Warm the arterial blood
B) Remove micro-emboli and air bubbles C) Decrease afterload on the heart D) Provide a reservoir for cardiotomy suction Answer: B Explanation: The arterial filter captures particulate matter and air, preventing embolic complications. Question 13. According to Poiseuille’s law, flow through a tube is most sensitive to changes in which variable? A) Length of the tube B) Viscosity of the fluid C) Radius of the tube D) Pressure gradient Answer: C Explanation: Flow is proportional to the fourth power of the radius; small changes dramatically affect resistance. Question 14. Ante-grade cardioplegia is delivered via: A) The coronary sinus B) The aortic root after cross-clamp C) Direct myocardial injection D) Retrograde perfusion catheter in the coronary sinus Answer: B Explanation: Ante-grade cardioplegia flows from the aortic root through the coronary arteries into the myocardium. Question 15. Retrograde cardioplegia is primarily used when:
Question 18. Ventricular venting during CPB is essential because it: A) Increases systemic vascular resistance B) Prevents left-ventricular distention and reduces myocardial oxygen consumption C) Improves coronary perfusion pressure D) Decreases the need for cardioplegia Answer: B Explanation: Venting removes blood that could otherwise cause ventricular over-filling and increased wall stress. Question 19. In a neonate with a large atrial septal defect, the primary perfusion goal during bypass is to: A) Maintain high systemic vascular resistance B) Avoid pulmonary over-circulation by controlling flow through the defect C) Use deep hypothermia only D) Provide continuous ventricular pacing Answer: B Explanation: Excess pulmonary flow through an ASD can cause edema; perfusion must balance systemic and pulmonary circulations. Question 20. The prime-to-patient blood volume ratio is most critical in: A) Adult coronary artery bypass grafting B) Pediatric cardiac surgery C) Lung transplantation D) Mechanical circulatory support Answer: B Explanation: Small pediatric patients have a high prime volume relative to their own blood volume, increasing hemodilution risk.
Question 21. During deep hypothermic circulatory arrest, the maximum safe arrest time for the brain is generally considered to be: A) 5 minutes B) 15 minutes C) 30 minutes D) 60 minutes Answer: C Explanation: With profound hypothermia, cerebral protection allows up to ~30 minutes of safe arrest. Question 22. In veno-arterial ECMO, the oxygenated blood is returned to the: A) Right atrium B) Pulmonary artery C) Aorta D) Left atrium Answer: C Explanation: VA-ECMO returns blood to the arterial system (often the aorta), providing both cardiac and respiratory support. Question 23. The primary advantage of veno-venous ECMO over VA-ECMO is: A) Ability to support cardiac output B) Lower risk of limb ischemia C) Higher systemic afterload D) Direct coronary perfusion Answer: B
D) 45 °C
Answer: C Explanation: HIPEC uses 41- 43 °C to enhance cytotoxic drug penetration while preserving tissue viability. Question 27. During lung procurement for transplantation, the preferred preservation solution is: A) Normal saline B) Lactated Ringer’s C) Perfadex (low-potassium dextran) D) Heparinized whole blood Answer: C Explanation: Perfadex provides low-potassium, dextran-based preservation minimizing edema and injury. Question 28. Autologous platelet-rich plasma (PRP) generated by intra-operative cell salvage is primarily used to: A) Reduce postoperative infection B) Decrease the need for allogeneic platelet transfusion C) Increase plasma oncotic pressure D) Provide coagulation factor VII Answer: B Explanation: PRP concentrates platelets, allowing targeted replacement and reducing donor exposure. Question 29. The primary parameter assessed by near-infrared spectroscopy (NIRS) during CPB is: A) Systemic arterial pressure
B) Cerebral tissue oxygen saturation (rSO₂) C) Mixed venous oxygen saturation (SvO₂) D) Central venous pressure Answer: B Explanation: NIRS measures regional cerebral oxygenation, guiding perfusion adequacy. Question 30. A sudden rise in arterial line pressure with a concurrent drop in venous return most likely indicates: A) Air embolism in the circuit B) Kinked arterial line C) Reservoir over-fill D) Pump speed increase Answer: B Explanation: A kink in the arterial line creates back-pressure, raising arterial line pressure while decreasing return. Question 31. The immediate action for a suspected air embolism in the CPB circuit is to: A) Increase pump flow B) Clamp the venous line and aspirate air C) Administer heparin bolus D) Decrease sweep gas flow Answer: B Explanation: Rapid isolation and aspiration of air prevents systemic embolization.
Explanation: Accurate records demonstrate adherence to standards and protect against malpractice claims. Question 35. OSHA regulations most directly affect perfusion practice in the area of: A) Patient consent B) Radiation safety C) Bloodborne pathogen exposure and engineering controls D) Billing practices Answer: C Explanation: OSHA sets standards for handling blood products and protecting staff from sharps and aerosolized pathogens. Question 36. The ABCP (American Board of Cardiovascular Perfusion) Code of Ethics requires perfusionists to: A) Prioritize research over patient care B) Maintain confidentiality and report unsafe practices C) Delegate all anticoagulation monitoring to nurses D) Accept any case regardless of competency Answer: B Explanation: Ethical standards emphasize confidentiality, safety, and professional responsibility. Question 37. In a scenario where a patient’s lactate rises from 1.5 mmol/L to 4.5 mmol/L during bypass, the most likely cause is: A) Hyperventilation B) Inadequate tissue perfusion or oxygen delivery C) Excessive heparin dosing
D) Over-heating of the perfusate Answer: B Explanation: Elevated lactate indicates anaerobic metabolism from insufficient oxygen delivery. Question 38. The “alpha-stat” strategy during hypothermic bypass maintains: A) Constant pH at the patient’s actual temperature B) Constant pH when corrected to 37 °C, allowing cerebral autoregulation C) Fixed CO₂ tension regardless of temperature D) Higher systemic vascular resistance Answer: B Explanation: Alpha-stat keeps the blood pH corrected to 37 °C, preserving autoregulatory mechanisms. Question 39. Which of the following is a contraindication to the use of milrinone during CPB? A) Severe hypotension B) Bradycardia C) Pulmonary hypertension D) Renal insufficiency Answer: A Explanation: Milrinone is a phosphodiesterase inhibitor that can cause vasodilation and exacerbate hypotension. Question 40. The primary purpose of a cardiotomy suction reservoir is to: A) Warm the arterial blood B) Collect and return shed blood from the surgical field
A) The oxygenator fails to remove CO₂ B) The native heart ejects poorly oxygenated blood to the upper body while ECMO supplies oxygenated blood to the lower body C) Sweep gas flow exceeds pump flow D) The arterial cannula is placed too distally Answer: B Explanation: Mixing of deoxygenated native output with oxygenated ECMO flow creates upper-body hypoxia. Question 44. Which of the following best describes the “prime-to-patient ratio” in pediatric CPB? A) Ratio of pump speed to cardiac output B) Volume of circuit prime divided by patient’s blood volume C) Ratio of arterial to venous line pressures D) Ratio of heparin dose to ACT Answer: B Explanation: The ratio reflects how much circuit fluid is added relative to the child’s own circulating volume. Question 45. The most common cause of postoperative bleeding after CPB is: A) Excessive protamine administration B) Platelet dysfunction secondary to hemodilution and hypothermia C) Inadequate heparin reversal D) Hyperfibrinolysis due to tranexamic acid overdose Answer: B Explanation: Dilutional thrombocytopenia and hypothermia impair platelet function, leading to bleeding.
Question 46. Which monitoring modality provides real-time assessment of mixed venous oxygen saturation (SvO₂) during bypass? A) Pulse oximetry B) Co-oximetry on arterial line C) Central venous oximetry probe D) Near-infrared spectroscopy (NIRS) on the forehead Answer: C Explanation: A central venous oximetry catheter measures SvO₂ directly from the pulmonary artery or central vein. Question 47. In a patient with severe aortic insufficiency undergoing CPB, the preferred venting strategy is: A) Left-ventricular apical vent B) Pulmonary artery vent C) Right-atrial vent D) No vent is needed Answer: A Explanation: An apical vent unloads the LV, preventing regurgitant volume accumulation. Question 48. Which of the following statements about heparin-induced thrombocytopenia (HIT) is true? A) It occurs within 24 hours of exposure B) Platelet count typically falls below 20,000/μL C) It is mediated by antibodies to the PF4-heparin complex D) Protamine reverses HIT
C) Provides the lowest resistance to flow among all oxygenators D) Is exclusively used for neonatal circuits Answer: B Explanation: Microporous oxygenators allow blood to flow through tiny pores, facilitating direct diffusion. Question 52. The primary advantage of using a centrifugal pump in pediatric circuits is: A) Ability to generate higher pressures than roller pumps B) Reduced priming volume and lower hemolysis risk C) Simpler manual control of flow D) Compatibility with all oxygenator types Answer: B Explanation: Centrifugal pumps are compact, generate less shear stress, and require less priming, which is critical in small patients. Question 53. During cardiopulmonary bypass, the systemic vascular resistance (SVR) is calculated using which formula? A) MAP × CO ÷ 80 B) (MAP – CVP) × 80 ÷ CO C) (CVP × CO) ÷ MAP D) CO ÷ (MAP – CVP) × 80 Answer: B Explanation: SVR = (Mean arterial pressure – Central venous pressure) × 80 ÷ Cardiac output. Question 54. In the management of a patient on VA-ECMO who develops left-ventricular distention, the most appropriate immediate intervention is:
A) Increase ECMO flow B) Initiate left-ventricular venting or intra-aortic balloon pump C) Decrease sweep gas flow D) Administer high-dose epinephrine Answer: B Explanation: LV distention compromises myocardial recovery; venting or IABP unloads the ventricle. Question 55. Which of the following best describes the “prime-draw” technique in pediatric CPB? A) Using a low-hematocrit prime to reduce viscosity B) Removing a portion of the prime after initiation to replace it with the patient’s blood C) Adding albumin to the prime to increase oncotic pressure D) Priming the circuit with crystalloid only Answer: B Explanation: Prime-draw withdraws some circuit fluid after bypass starts, reducing hemodilution. Question 56. The primary purpose of administering mannitol during CPB is to: A) Increase oncotic pressure and reduce tissue edema B) Serve as an anticoagulant C) Provide a source of glucose for the myocardium D) Decrease arterial line pressure Answer: A Explanation: Mannitol is an osmotic diuretic that limits cellular swelling and improves renal perfusion.
