Final answer:
The elevated respiratory rate in a child after ingesting aspirin is an attempt to compensate for metabolic acidosis by increasing respiration to drive off CO2, leading to respiratory alkalosis.
Step-by-step explanation:
A child presenting with an elevated respiratory rate following an ingestion of aspirin is likely experiencing respiratory alkalosis as a compensatory mechanism. Aspirin overdose, otherwise known as salicylate toxicity, initially leads to a metabolic acidosis that the body attempts to compensate for by increasing respiratory rate to blow off CO2 and reduce the acidity of the blood. The increased respiratory rate observed by the nurse, therefore, is an attempt by the body to correct the underlying metabolic acidosis by hyperventilating to reduce the carbonic acid levels.