Final answer:
The most important symptoms to be alert for in a child with fever, rash, and altered mental status en route to the hospital are respiratory distress and signs of encephalitis.
Step-by-step explanation:
When escorting a 7-year-old child with an altered mental status, high fever, and a generalized rash to the hospital, one should be most alert for changes in respiratory status or signs of respiratory distress. The symptoms described could suggest a serious infection, such as measles or a severe viral illness, which in some cases can lead to complications like pneumonia or encephalitis, a condition that causes inflammation of the brain and can be life-threatening.
It is crucial to monitor the child's breathing and provide continuous oxygen supplementations as needed. Monitoring vital signs and watching for any neurological changes such as seizures or further alteration in mental status is also essential.