CVP Technical Skills and Equipment Operation 3 — Questions and Answers
Question 1: The primary purpose of the cardiotomy reservoir in a CPB circuit is to:
- Collect and filter shed blood from the surgical field for reinfusion (Correct answer)
- Store priming solution before bypass
- Provide a backup oxygenation source
- Regulate venous line pressure
Correct answer: Collect and filter shed blood from the surgical field for reinfusion
The cardiotomy reservoir collects blood suctioned from the surgical field, filters it, and returns it to the venous reservoir for reinfusion.
Question 2: When priming a CPB circuit, crystalloid prime is preferred over blood prime primarily because it:
- Reduces exposure to allogeneic blood products and associated risks (Correct answer)
- Provides superior oxygen-carrying capacity
- Eliminates the need for anticoagulation
- Maintains higher colloid osmotic pressure
Correct answer: Reduces exposure to allogeneic blood products and associated risks
Crystalloid prime avoids donor blood exposure risks including transfusion reactions, infection, and immunologic sensitization.
Question 3: A perfusionist observes plasma-colored urine turning pink during CPB. This most likely indicates:
- Hemolysis with hemoglobinuria (Correct answer)
- Renal failure
- Bladder injury from catheter
- Myoglobinuria from muscle breakdown
Correct answer: Hemolysis with hemoglobinuria
Pink or red urine during CPB indicates hemoglobinuria from hemolysis, which can result from mechanical trauma, air exposure, or excessive suction.
Question 4: The recommended activated clotting time (ACT) target during standard cardiopulmonary bypass with unfractionated heparin is:
- Greater than 400–480 seconds (Correct answer)
- Greater than 200–250 seconds
- Greater than 150–180 seconds
- Greater than 300–350 seconds
Correct answer: Greater than 400–480 seconds
An ACT greater than 400–480 seconds is required to prevent clotting within the CPB circuit and is the standard target during bypass.
Question 5: Which component of the CPB circuit is responsible for eliminating carbon dioxide from the blood?
- The membrane oxygenator via the sweep gas flow (Correct answer)
- The arterial line filter
- The venous reservoir
- The heat exchanger
Correct answer: The membrane oxygenator via the sweep gas flow
CO2 elimination in the oxygenator is controlled by adjusting sweep gas flow rate; higher sweep gas increases CO2 removal.
Question 6: During hypothermic circulatory arrest, cerebral protection is primarily achieved by:
- Reducing cerebral metabolic rate through deep hypothermia (Correct answer)
- Administering corticosteroids
- Increasing systemic arterial pressure
- Delivering retrograde coronary sinus perfusion
Correct answer: Reducing cerebral metabolic rate through deep hypothermia
Deep hypothermia (≤18°C) dramatically reduces cerebral oxygen consumption, allowing safe periods of circulatory arrest.
Question 7: A right-angle venous cannula placed in the right atrium is preferred over a straight cannula when:
- Bicaval cannulation is required for open cardiac procedures (Correct answer)
- Minimizing circuit prime volume is the priority
- Higher venous flow rates are needed quickly
- Operating without a cardiotomy suction system
Correct answer: Bicaval cannulation is required for open cardiac procedures
Right-angle cannulas allow placement in the superior and inferior vena cava for bicaval cannulation, enabling a bloodless right heart field.
CVP Technical Skills and Equipment Operation 3
The primary purpose of the cardiotomy reservoir in a CPB circuit is to: