A trauma patient arrives in the emergency department via EMS, bleeding profusely from a wound on the left lower extremity. A medical alert necklace indicates he is on heparin therapy. The nurse will most likely administer which medication to counteract the action of heparin?

Choice A reason: Calcium gluconate treats hypocalcemia or hyperkalemia, not heparin overdose. Heparin enhances antithrombin, prolonging clotting time, causing bleeding. Calcium does not reverse this anticoagulant effect, making it an incorrect choice for managing profuse bleeding in a patient on heparin therapy. Choice B reason: Protamine sulfate is the antidote for heparin, binding to it and neutralizing its anticoagulant effect, rapidly reversing bleeding. In a trauma patient with profuse bleeding, this is critical to restore clotting and prevent hypovolemic shock, making it the most likely medication to administer. Choice C reason: Enoxaparin, a low-molecular-weight heparin, is an anticoagulant, not an antidote. Administering it would worsen bleeding in a patient already on heparin. Protamine sulfate is needed to reverse heparin’s effect, making enoxaparin an incorrect choice for this emergency scenario. Choice D reason: Vitamin K reverses warfarin, not heparin, by promoting clotting factor synthesis. Heparin’s immediate anticoagulant effect requires protamine sulfate for rapid neutralization. Vitamin K is ineffective in this context, making it an incorrect choice for managing acute bleeding in a heparinized patient.