A client receiving whole blood experiences dyspnea, wheezing, and hypotension. What medication will the nurse administer?

In the scenario described, the client is exhibiting symptoms such as dyspnea, wheezing, and hypotension after receiving a blood transfusion. These symptoms suggest an allergic or anaphylactic reaction. Epinephrine is the first-line treatment for such severe allergic reactions, as it acts quickly to reverse the effects of anaphylaxis by causing vasoconstriction, increasing heart rate, and dilating airways, thus alleviating respiratory distress.

Using epinephrine helps to stabilize the patient's condition by addressing the potentially life-threatening symptoms they are experiencing. The medication is essential in managing acute respiratory distress and cardiovascular instability associated with an anaphylactic response.

The other medications listed do not serve this specific purpose in the context of an allergic reaction to blood transfusion. Heparin is an anticoagulant used to prevent blood clots; acetaminophen is used primarily for pain relief and fever reduction, and aspirin is an antiplatelet that helps prevent blood clots, but none of these medications would effectively treat an anaphylactic reaction as epinephrine does. Thus, administering epinephrine is the critical intervention in this emergency situation.