A nurse is caring for an adolescent who has sickle-cell anemia. Which of the following manifestations indicates acute chest syndrome and should be immediately reported to the provider?

Rationale: A. A mildly elevated temperature may indicate infection or inflammation, which is important in sickle cell disease, but it is not a defining or immediate indicator of acute chest syndrome. Acute chest syndrome typically presents with more severe respiratory compromise along with fever ≥ 38.5°C (101.3°F) or higher in many cases. B. Acute chest syndrome is characterized by respiratory distress such as tachypnea, hypoxia, and increased work of breathing. Bradypnea (slow respiratory rate) is not typical and would be more concerning for central nervous system depression or late-stage respiratory failure rather than early acute chest syndrome. C. Sneezing is associated with upper respiratory irritation or allergic rhinitis and is not related to acute chest syndrome. Acute chest syndrome involves the lungs and is typically caused by infection, fat embolism, or vaso-occlusion leading to pulmonary complications. D. Substernal retractions indicate increased work of breathing and respiratory distress. In a client with sickle cell disease, this is a serious finding that may indicate acute chest syndrome, which is a medical emergency characterized by chest pain, hypoxia, fever, cough, and respiratory compromise.