A nurse is monitoring a client who is receiving a transfusion of packed RBCs. Which of the following findings should the nurse identify as an indication that the client should receive diphenhydramine?

A. Vomiting: Vomiting may indicate a severe transfusion reaction, such as hemolytic or septic reaction, but it is not typically treated with diphenhydramine. Immediate intervention would focus on stopping the transfusion and assessing the client’s vital signs. B. Pulmonary congestion: Pulmonary congestion can signal circulatory overload (TACO) rather than an allergic reaction. Management includes slowing or stopping the transfusion and providing diuretics if ordered, not administering diphenhydramine. C. Urticaria: Urticaria, or hives, is a common manifestation of a mild allergic transfusion reaction. Diphenhydramine, an antihistamine, is indicated to relieve itching and prevent progression of the allergic response. D. Jugular vein distention: Jugular vein distention is a sign of fluid overload or heart failure, not an allergic reaction. It requires assessment of fluid status and cardiovascular support rather than diphenhydramine administration.