A nurse is administering packed RBCs to a client. The client reports chills, lower back pain, and nausea 10 min after the infusion begins. Which of the following actions should the nurse take first?

Blood transfusion reactions can occur rapidly and may become life-threatening if not managed promptly. Packed red blood cells (RBCs) can trigger acute hemolytic reactions, especially within the first few minutes of infusion. Early signs include chills, back pain, fever, nausea, and a sense of impending doom. Immediate recognition and interruption of the transfusion are critical to prevent further hemolysis and systemic complications. A. Checking the client’s vital signs is important but should not delay immediate action. Vital signs provide assessment data, but the priority is to stop the source of the reaction first to prevent further exposure to incompatible blood. Assessment follows stabilization steps. B. Stopping the infusion is the priority action because the client is exhibiting classic signs of an acute transfusion reaction, including chills, lower back pain, and nausea. These symptoms suggest possible hemolytic reaction, and discontinuing the blood prevents further antigen–antibody interaction and worsening of the reaction. C. Administering oxygen may be necessary later if the client develops respiratory distress or hypoxia, but it is not the first action. The priority is to stop the transfusion immediately to prevent progression of the reaction. Oxygen supports tissue perfusion but does not address the underlying cause. D. Collecting a urine sample is done after the transfusion is stopped and is used to assess for hemoglobinuria, which can occur in hemolytic reactions. It is not an immediate priority action because it does not prevent ongoing immune destruction of red blood cells. Stabilization of the client comes first.