Final answer:
Piaget's theory of cognitive development helps pediatric nurses design appropriate therapeutic play interventions for ill toddlers.
Step-by-step explanation:
The theory that would help a pediatric nurse design an appropriate therapeutic play intervention for ill toddlers is Piaget's theory of cognitive development.
Piaget's theory focuses on the cognitive and intellectual development of children and emphasizes how children construct their understanding of the world through play and interaction. It suggests that children progress through different stages of cognitive development, and their play activities can be designed to support their specific developmental needs.
By understanding Piaget's theory, a pediatric nurse can assess the cognitive abilities and developmental stage of an ill toddler and design therapeutic play interventions that are suitable for their level of understanding and promote their cognitive growth and emotional well-being.