CVP Technical Skills and Equipment Operation 2 — Questions and Answers
Question 1: When setting up a centrifugal pump head for cardiopulmonary bypass, which parameter is the primary determinant of flow output?
- Revolutions per minute (RPM) (Correct answer)
- Inlet pressure
- Outlet resistance
- Fluid viscosity
Correct answer: Revolutions per minute (RPM)
Centrifugal pump flow is primarily determined by RPM, though it is also influenced by preload and afterload conditions.
Question 2: During cardiopulmonary bypass, a sudden rise in arterial line pressure with no change in pump flow most likely indicates:
- Aortic dissection or cannula obstruction (Correct answer)
- Venous air lock
- Oxygenator failure
- Heater-cooler malfunction
Correct answer: Aortic dissection or cannula obstruction
A sudden increase in arterial line pressure with stable flow suggests outflow obstruction such as aortic dissection or a kinked/obstructed arterial cannula.
Question 3: Which type of oxygenator design is exclusively used in modern clinical cardiopulmonary bypass circuits?
- Hollow-fiber membrane oxygenator (Correct answer)
- Bubble oxygenator
- Screen oxygenator
- Rotating disc oxygenator
Correct answer: Hollow-fiber membrane oxygenator
Hollow-fiber membrane oxygenators have replaced all other designs in modern clinical practice due to superior biocompatibility and gas transfer efficiency.
Question 4: A perfusionist notices the venous reservoir level is dropping rapidly despite adequate venous return. The most immediate action is to:
- Reduce pump flow to prevent air entrainment (Correct answer)
- Increase cardioplegia delivery rate
- Switch to the backup pump head
- Increase arterial flow to compensate
Correct answer: Reduce pump flow to prevent air entrainment
Reducing pump flow prevents the reservoir from emptying and air from entering the arterial line, which is the most immediate life-threatening risk.
Question 5: The purpose of an arterial line filter in a CPB circuit is to:
- Remove microemboli and gaseous emboli before they reach the patient (Correct answer)
- Regulate arterial blood pressure
- Measure oxygen saturation of perfusate
- Control perfusate temperature
Correct answer: Remove microemboli and gaseous emboli before they reach the patient
Arterial line filters trap particulate matter and gaseous microemboli, protecting the patient from embolic events during bypass.
Question 6: During rewarming on CPB, the maximum recommended temperature gradient between the heater-cooler water temperature and the patient's blood temperature is:
- 10°C (Correct answer)
- 20°C
- 5°C
- 15°C
Correct answer: 10°C
A gradient of no more than 10°C between heater-cooler water and blood temperature prevents gas supersaturation and gaseous microemboli formation.
Question 7: Which monitoring parameter is most useful for detecting venous air lock during cardiopulmonary bypass?
- Sudden decrease in venous return with distended venous line (Correct answer)
- Rising arterial line pressure
- Decreasing pump RPM
- Increasing mixed venous oxygen saturation
Correct answer: Sudden decrease in venous return with distended venous line
Venous air lock presents as a sudden decrease in venous drainage with visible air and distension in the venous line, obstructing gravity siphon drainage.
CVP Technical Skills and Equipment Operation 2
When setting up a centrifugal pump head for cardiopulmonary bypass, which parameter is the primary determinant of flow output?