Protamine is used in CABG to reverse heparin. Which statement correctly describes its use and potential adverse effects?

• A. Protamine reverses heparin; adverse reactions include hypotension, anaphylaxis, pulmonary hypertension, and rapid bolus effects; dosing is weight-based and titrated.
• B. Protamine reverses platelets; adverse effects are decreased bleeding.
• C. Protamine is used to prevent infection.
• D. Protamine is given only as a fixed bolus regardless of weight.

Answer: (A)

Protamine neutralizes heparin, which is why it’s used at the end of CABG to restore normal coagulation after the bypass run. The correct statement reflects both what protamine does and the real clinical considerations: it reverses heparin, but its administration isn’t without risk. Adverse effects can include low blood pressure (hypotension), allergic-type reactions such as anaphylaxis, and pulmonary hypertension from vasoconstriction or histamine release. A rapid bolus can trigger these effects more intensely, so protamine is given as a carefully titrated, weight-based dose rather than a fixed rapid injection. In practice, dosing is calculated relative to the amount of heparin given and is adjusted based on the patient’s response, often guided by coagulation tests and intraoperative monitoring.

Context helps: protamine’s action is specific to heparin’s anticoagulant effect; it is not used to affect platelets or to prevent infection. Giving protamine as a fixed bolus or without weight-based dosing can increase the risk of the adverse reactions described. Additional risk factors for reactions include prior exposure to protamine or certain insulin formulations, or fish allergies, so clinicians monitor closely and have treatment ready if a reaction occurs.