A patient has received an overdose of intravenous heparin, and is showing signs of excessive bleeding. Which substance is the antidote for heparin overdose?

Correct Answer: C

Rationale: Protamine sulfate is the antidote for heparin overdose. Heparin is an anticoagulant medication that works by inhibiting the action of thrombin and factor Xa. Protamine works by binding to heparin and neutralizing its anticoagulant effects. This helps to reverse the effects of heparin and control excessive bleeding in cases of overdose. It is important to administer protamine sulfate promptly to counteract the effects of heparin and prevent further bleeding complications. Options A, B, and D are not the correct antidotes for heparin overdose.

Correct Answer: B

Rationale: The nurse monitors the aPTT to check the effectiveness of heparin therapy in preventing and treating blood clots. Heparin acts by inhibiting the clotting cascade, specifically by enhancing the activity of antithrombin III, which inactivates clotting factors such as thrombin and factor Xa. The aPTT measures the intrinsic pathway of the clotting cascade, which is affected by heparin therapy. By monitoring the patient's aPTT levels, the nurse can ensure that the patient is within the therapeutic range for heparin therapy to be effective in preventing further clot formation. Monitoring bleeding times, PT/INR, or vitamin K levels is not typically done to assess heparin therapy effectiveness.

Correct Answer: C

Rationale: Valproate belongs to the category class of anticonvulsants, which are medications primarily used to treat seizures and epilepsy. Valproate is also used as a treatment for vascular headaches, such as migraines. It is not categorized as an anticoagulant, antianxiety medication (such as benzodiazepines), or a mood stabilizer.

Correct Answer: C

Rationale: A month after receiving a blood transfusion, the development of a fever in an immunocompromised patient can be indicative of graft-versus-host disease (GVHD). GVHD is a condition where the donor immune cells attack the recipient's tissues, manifesting as fever, rash, liver dysfunction, and gastrointestinal symptoms. It typically occurs a few weeks to several months after a blood transfusion, especially in immunocompromised individuals. An allergic response to medication or myelosuppression would typically present earlier after the transfusion, while nothing related to the blood transfusion does not explain the fever in this context.

Correct Answer: B

Rationale: Warfarin is an anticoagulant medication that works by inhibiting the body's ability to use vitamin K to form clotting factors. In cases of excessive anticoagulation or bleeding due to Warfarin, the antidote is vitamin K. Vitamin K helps the body produce clotting factors, thereby reversing the effects of Warfarin and promoting the blood to clot normally. Other medications like Narcan, Glucagon, and Vitamin B do not have a direct antidote effect for Warfarin toxicity.