Final answer:
The nurse should administer platelet transfusions to the child with aplastic anemia to prevent bleeding and promote hemostasis.
Step-by-step explanation:
The nurse should incorporate the nursing intervention of administering platelet transfusions into the plan of care for the child with aplastic anemia. Aplastic anemia is characterized by a decrease in all types of blood cells, including platelets. The platelet count of 150,000 cells/mm³ is within the normal range, but still lower than the optimal level. Platelet transfusions can help prevent bleeding and promote hemostasis in the child.