CCP Intraoperative Procedures & Patient Monitoring 3 — Questions and Answers
Question 1: During deep hypothermic circulatory arrest (DHCA), the recommended nasopharyngeal temperature target before stopping flow is:
- 28–30°C
- 22–25°C
- 15–18°C (Correct answer)
- 10–12°C
Correct answer: 15–18°C
DHCA is typically performed at 15–18°C nasopharyngeal temperature to maximize cerebral protection by minimizing metabolic demand.
Question 2: Which electrolyte abnormality is most commonly associated with the use of cardioplegia solution and requires monitoring during cardiac surgery?
- Hyponatremia
- Hyperkalemia (Correct answer)
- Hypercalcemia
- Hypermagnesemia
Correct answer: Hyperkalemia
Cardioplegia solutions contain high concentrations of potassium to arrest the heart, and systemic hyperkalemia can result from cardioplegia delivery and washback.
Question 3: Pulsatile perfusion during CPB is theorized to provide benefit primarily by:
- Reducing heparin requirements
- Improving microcirculatory flow and lymphatic drainage (Correct answer)
- Increasing systemic vascular resistance
- Decreasing hemodilution
Correct answer: Improving microcirculatory flow and lymphatic drainage
Pulsatile flow is thought to better maintain microcirculatory perfusion and lymphatic function compared to non-pulsatile laminar flow.
Question 4: When using alpha-stat pH management during hypothermic CPB, the perfusionist:
- Corrects pH and PCO2 values to 37°C before interpreting
- Reports uncorrected blood gas values measured at 37°C (Correct answer)
- Adds CO2 to maintain a temperature-corrected pH of 7.40
- Targets a temperature-corrected PaCO2 of 40 mmHg
Correct answer: Reports uncorrected blood gas values measured at 37°C
Alpha-stat management uses blood gas values measured at 37°C without temperature correction, maintaining electrochemical neutrality of proteins.
Question 5: Which type of venous cannulation provides the best venous drainage for complex cardiac procedures requiring a bloodless operative field?
- Single two-stage venous cannula via right atrium
- Bicaval cannulation with separate SVC and IVC cannulas (Correct answer)
- Femoral vein cannulation alone
- Pulmonary artery vent only
Correct answer: Bicaval cannulation with separate SVC and IVC cannulas
Bicaval cannulation with separate superior vena cava (SVC) and inferior vena cava (IVC) cannulas with caval snares provides complete caval occlusion for a bloodless right heart field.
Question 6: During CPB, a sudden decrease in venous return with unchanged patient positioning most likely indicates:
- Increased cardiac output recovery
- Venous line obstruction, air lock, or cannula malposition (Correct answer)
- Increased systemic vascular resistance
- Oxygenator membrane failure
Correct answer: Venous line obstruction, air lock, or cannula malposition
A sudden drop in venous return at constant patient position suggests a mechanical problem such as venous line kinking, air lock in the venous line, or venous cannula malposition.
Question 7: The purpose of a left ventricular vent during CPB is to:
- Deliver cardioplegia to the left coronary system
- Decompress the left ventricle and prevent distension (Correct answer)
- Monitor left atrial pressure continuously
- Provide retrograde cardioplegia delivery
Correct answer: Decompress the left ventricle and prevent distension
An LV vent decompresses the left ventricle to prevent distension from bronchial blood return, which could cause myocardial injury and impair the surgical field.
CCP Intraoperative Procedures & Patient Monitoring 3
During deep hypothermic circulatory arrest (DHCA), the recommended nasopharyngeal temperature target before stopping flow is: