What should a nurse do first when preparing to administer 2 units of blood to a client with an IV in place?

The initial step a nurse should take when preparing to administer blood to a client already has an IV in place is to start a second IV with isotonic saline. This is crucial for several reasons. Firstly, it ensures that the client can receive the transfusion while maintaining access to a separate line for additional fluids or medications, if necessary.

Having isotonic saline in a second IV line helps prevent complications if any reactions occur during the transfusion, as it allows for the rapid administration of fluids. Moreover, maintaining a separate line allows the nurse to flush the blood transfusion line, ensuring that the blood is administered effectively and without clots or air bubbles.

While other options might seem appropriate at different points in the process, starting a second IV ensures the safety and continuous management of the patient's needs during the blood transfusion.