Final answer:
The earliest sign of increased ICP in a child after a head injury is a change in the level of consciousness. Apnea, posturing, and tachycardia may also occur but typically present later in the progression of symptoms.
Step-by-step explanation:
The nurse is monitoring a child for signs of increased intracranial pressure (ICP) after a head injury. The earliest sign of increased ICP is a change in the level of consciousness (LOC). Other signs, such as apnea, posturing, and tachycardia also occur with increased ICP but may manifest later.
The body's homeostasis, including factors like temperature, respiratory rate, and blood pressure can reflect underlying problems like increased ICP. Observing these signs is part of the rapid assessment of neurological function in emergency and healthcare settings.