Final answer:
A cool IV site may indicate poor perfusion or infiltration, requiring new venous access. The IV's wrist location, 72-hour duration, or 20-gauge catheter alone don't necessitate a new site unless complications are present.
Step-by-step explanation:
When assessing a client's peripheral intravenous (IV) access prior to initiating a blood transfusion, the nurse should look for signs of potential complications. A finding that would prompt the nurse to initiate new venous access would be a complication such as phlebitis, infiltration, infection, or a significant obstruction. In this scenario, the fact that the skin around the IV site is cool to the touch could indicate poor perfusion or infiltration, which is a potential complication where IV fluids enter the surrounding tissue instead of the vein. This would necessitate the establishment of new venous access.