Final answer:
The nurse should apply a cold compress to the injured child to help reduce capillary permeability and edema.
Step-by-step explanation:
The nurse should apply a cold compress to the injured child to help constrict capillaries and reduce capillary permeability and edema. Cold temperature causes vasoconstriction, which narrows the blood vessels and reduces blood flow to the injured area, thereby reducing swelling and inflammation. Examples of cold compresses include ice packs, cold towels, or frozen vegetables wrapped in a cloth.