Pharmacology and Blood Management Flashcards

What is the mechanism of action of heparin in preventing clotting?

Answer: Heparin binds to antithrombin III, dramatically accelerating its inhibition of thrombin and Factor Xa

Heparin potentiates the natural anticoagulant antithrombin III, which then rapidly inhibits key clotting factors including thrombin and Factor Xa.

What vasopressor is commonly used to maintain blood pressure during bypass?

Answer: Phenylephrine

Phenylephrine is an alpha-adrenergic agonist commonly used during bypass to increase systemic vascular resistance and maintain adequate mean arterial pressure.

What is the role of mannitol in cardiopulmonary bypass?

Answer: It acts as an osmotic diuretic to maintain urine output and reduce cellular swelling

Mannitol is added to the bypass circuit as an osmotic diuretic that helps maintain kidney function and reduces tissue edema during the procedure.

When is blood transfusion indicated during cardiopulmonary bypass?

Answer: When hematocrit drops below a critical threshold, typically around 21-24%

Transfusion is indicated when hemodilution reduces the hematocrit below the level needed to maintain adequate oxygen delivery, typically around 21-24%.

What is the purpose of adding sodium bicarbonate during bypass?

Answer: To correct metabolic acidosis by buffering excess acid in the blood

Sodium bicarbonate is used to correct metabolic acidosis, which can develop during bypass due to inadequate perfusion or hypothermia.

What is epsilon-aminocaproic acid (Amicar) used for during cardiac surgery?

Answer: To inhibit fibrinolysis and reduce bleeding

Amicar inhibits the breakdown of blood clots (fibrinolysis), helping to reduce bleeding during and after cardiac surgery.