BCA Cardiovascular Anesthesia 3 — Questions and Answers
Question 1: Which cardioplegia delivery method provides the most uniform myocardial protection in the presence of significant coronary artery disease?
- Antegrade cardioplegia via aortic root
- Retrograde cardioplegia via coronary sinus
- Combined antegrade and retrograde delivery (Correct answer)
- Intermittent antegrade warm blood cardioplegia
Correct answer: Combined antegrade and retrograde delivery
Combined antegrade and retrograde delivery ensures distribution to areas that may not receive adequate cardioplegia through stenotic coronary arteries alone.
Question 2: The normal activated clotting time (ACT) target for full anticoagulation during cardiopulmonary bypass is:
- >200 seconds
- >300 seconds
- >400 seconds (Correct answer)
- >480 seconds
Correct answer: >400 seconds
An ACT >400 seconds (some centers use >480 s) is required to prevent thrombus formation within the CPB circuit.
Question 3: A patient develops acute right heart failure immediately after separation from CPB following mitral valve repair. The FIRST intervention should be:
- Initiate mechanical circulatory support with IABP
- Increase PEEP to reduce RV preload
- Administer inhaled nitric oxide to reduce PVR (Correct answer)
- Give epinephrine 100 mcg IV bolus
Correct answer: Administer inhaled nitric oxide to reduce PVR
Inhaled nitric oxide selectively reduces pulmonary vascular resistance, directly unloading the right ventricle without causing systemic hypotension.
Question 4: Which ECG finding during cardiac surgery indicates adequate diastolic arrest with cold potassium cardioplegia?
- Junctional rhythm at 40 bpm
- Flat isoelectric line (asystole) (Correct answer)
- Ventricular fibrillation
- Sinus bradycardia at 30 bpm
Correct answer: Flat isoelectric line (asystole)
Cardioplegia depolarizes myocardial cells by elevating extracellular potassium, causing diastolic arrest manifested as an isoelectric ECG.
Question 5: During aortic arch surgery with circulatory arrest, cerebral protection is best achieved by:
- Hypothermia alone to 15-18°C nasopharyngeal temperature
- Antegrade selective cerebral perfusion with moderate hypothermia (Correct answer)
- Retrograde cerebral perfusion via SVC with deep hypothermia
- Barbiturate coma induction prior to arrest
Correct answer: Antegrade selective cerebral perfusion with moderate hypothermia
Antegrade selective cerebral perfusion (ASCP) with moderate hypothermia (24-28°C) provides direct cerebral blood flow and metabolic suppression, offering superior neuroprotection.
Question 6: Milrinone is preferred over dobutamine for right ventricular failure post-cardiac surgery primarily because:
- Milrinone has a shorter half-life allowing rapid titration
- Milrinone reduces PVR while increasing RV contractility (Correct answer)
- Milrinone does not cause tachycardia unlike dobutamine
- Milrinone has no effect on systemic blood pressure
Correct answer: Milrinone reduces PVR while increasing RV contractility
Milrinone, a phosphodiesterase-3 inhibitor, simultaneously increases inotropy and causes pulmonary vasodilation, directly addressing both components of RV failure.
Question 7: Which intraoperative finding on TEE most reliably indicates adequate de-airing of the left ventricle before cross-clamp removal?
- Absence of air bubbles in left atrium
- Normal LV wall motion in all segments
- Absence of echogenic particles in LV cavity and aorta (Correct answer)
- Normalization of LVEF on visual estimation
Correct answer: Absence of echogenic particles in LV cavity and aorta
Absence of echogenic (bright) particles in the LV cavity and ascending aorta on TEE confirms adequate de-airing, reducing risk of air embolism.
BCA Cardiovascular Anesthesia 3
Which cardioplegia delivery method provides the most uniform myocardial protection in the presence of significant coronary artery disease?