What observation should make the nurse suspect dehydration in a school-age child?

Dry mucous membranes serve as a significant indicator of dehydration in a school-age child. In healthy children, mucous membranes typically appear moist and well-hydrated. When a child is dehydrated, the lack of adequate fluid leads to decreased saliva production and a subsequent drying of these membranes. This physical examination finding can provide an immediate visual cue to the nurse regarding the child's hydration status, allowing for prompt assessment and intervention.

In contrast, increased activity level might not indicate dehydration; children can be quite active regardless of their hydration status. Sounds of wheezing generally point to respiratory issues rather than hydration problems. Lastly, wet diaper appearances are more indicative of adequate hydration, as they show that the child is urinating sufficiently and maintaining fluid balance.