CVP Myocardial Protection and Cardioplegia Flashcards

What is the primary purpose of cardioplegia solution in cardiac surgery?

Answer: To arrest the heart and protect the myocardium from ischemic injury

Cardioplegia solution is used to induce electromechanical cardiac arrest and provide metabolic protection to the myocardium during ischemia.

Which electrolyte is primarily responsible for inducing cardiac arrest in cardioplegia solution?

Answer: Potassium

High concentrations of potassium (15–30 mEq/L) depolarize the myocardial cell membrane and arrest the heart in diastole.

What temperature range is typically used for cold blood cardioplegia delivery?

Answer: 4–10°C

Cold cardioplegia (4–10°C) reduces myocardial metabolic demand by lowering temperature, slowing enzymatic reactions.

Antegrade cardioplegia is delivered via which route?

Answer: Aortic root or coronary ostia

Antegrade cardioplegia follows normal coronary blood flow, delivered into the aortic root proximal to the cross-clamp or directly into the coronary ostia.

Retrograde cardioplegia is delivered via which structure?

Answer: Coronary sinus

Retrograde cardioplegia is infused through the coronary sinus, flowing backwards through the venous coronary system to perfuse the myocardium.

What is the typical potassium concentration in a standard cardioplegia solution compared to normal plasma?

Answer: Markedly elevated (15–30 mEq/L)

Standard cardioplegia contains 15–30 mEq/L of potassium, roughly 4–6 times the normal plasma level, sufficient to arrest the heart.