CVP Myocardial Protection and Cardioplegia Flashcards

What is myocardial ischemia-reperfusion injury?

Answer: Tissue damage that paradoxically occurs when blood flow is restored to ischemic myocardium

Reperfusion injury results from oxidative stress, calcium overload, and inflammatory activation that occur when oxygenated blood returns to previously ischemic tissue.

Which cardioplegia additive helps scavenge free radicals to limit reperfusion injury?

Answer: Mannitol

Mannitol is an osmotic agent and free-radical scavenger added to some cardioplegia formulations to reduce oxidative reperfusion injury.

What is meant by 'integrated myocardial protection' during cardiac surgery?

Answer: Combining multiple complementary strategies (temperature, cardioplegia type, route, additives) to optimize protection

Integrated myocardial protection combines systemic temperature management, cardioplegia composition and route, ischemic preconditioning, and reperfusion strategies for optimal outcomes.

What is the typical maximum safe aortic cross-clamp time achievable with modern myocardial protection techniques?

Answer: Up to 2–4 hours with adequate protection

With optimal cardioplegia, hypothermia, and re-dosing intervals, cross-clamp times of 2–4 hours are achievable with acceptable myocardial outcomes in most patients.

What surgical finding suggests adequate myocardial protection during cold cardioplegia delivery?

Answer: Pale, arrested, flaccid heart with surface temperature below 15°C

A pale, arrested, flaccid heart with low surface temperature indicates successful electrical arrest, metabolic suppression, and adequate cooling.

Why is the left ventricle particularly vulnerable to inadequate cardioplegia distribution?

Answer: It has greater muscle mass and higher baseline oxygen demand, making ischemia more consequential

The LV's greater wall thickness and higher oxygen consumption mean inadequate distribution results in faster energy depletion and greater ischemic damage.