What action should a nurse take when a patient shows signs of an allergic reaction during a blood transfusion?

When a patient exhibits signs of an allergic reaction during a blood transfusion, the most critical and appropriate response is to stop the transfusion immediately. This action is essential to prevent further exposure to the allergen that could exacerbate the allergic response, which can range from mild symptoms such as itching and rash to more severe reactions like anaphylaxis.

Stopping the transfusion promptly allows for the implementation of necessary interventions, such as administering antihistamines or other medications to treat the reaction. It also ensures the patient's safety, as the ongoing infusion could lead to more severe complications. After halting the transfusion, the healthcare team can assess the patient's condition and act according to hospital protocols for managing transfusion reactions.

Continuing the transfusion, notifying the healthcare provider only afterward, or administering aspirin are not appropriate first reactions. Continuing the transfusion risks worsening the allergic reaction, while notifying the provider after halting the transfusion could delay needed treatment. Similarly, aspirin is not indicated for immediate management of allergic reactions during transfusions and could potentially complicate the patient's condition.