A nurse is caring for a client who is receiving a blood transfusion and exhibits signs of a transfusion reaction. What is the priority intervention the nurse should take?

Administer 0.9% sodium chloride through the existing blood transfusion line.

Notify the provider and document the reaction before any other action.

Stop the transfusion and maintain IV access by infusing normal saline through new tubing.

Monitor vital signs every 30 minutes during the transfusion.