A nurse is reviewing data for four children. Which of the following children should the nurse assess first?

Rationale: A. Roseola with a fever of 39°C (102.2°F) is concerning but not immediately life-threatening; fever can be managed after assessing higher-priority conditions. B. A urine specific gravity of 1.016 in a child with diabetes insipidus is within a moderate range and does not indicate acute risk. C. A PCO2 of 37 mm Hg in a child with asthma is within normal limits (35–45 mm Hg) and does not require immediate intervention. D. Severe chest pain in a child with sickle cell anemia may indicate acute chest syndrome, a potentially life-threatening complication requiring immediate assessment and intervention.