Final answer:
The emergency nurse's immediate action should be to apply pressure to the bleeding knee joint to help control the bleeding.
Step-by-step explanation:
The emergency nurse's immediate action in this situation should be to apply pressure to the bleeding knee joint to help control the bleeding.
As a patient with hemophilia, their blood lacks clotting factors which are necessary for blood to clot normally. Therefore, the nurse should focus on preventing further bleeding and promoting clotting by applying pressure to the affected area and immobilizing the knee joint.
This action will help minimize further bleeding and potential damage to the joint.