When auscultating breath sounds of an infant with respiratory syncytial virus, which assessment would the nurse immediately report?

A. Heart rate decreases from 110 to 100 beats/minute: A small drop within normal HR range is not alarming unless associated with other symptoms. B. "Quiet chest" from previous assessment of wheezing: This is a red flag in RSV. A sudden decrease in wheezing or breath sounds may indicate impending respiratory failure due to fatigue or poor air entry. C. Oxygen saturation of 90%: While low, this is a common finding in RSV and typically managed with supplemental oxygen. It’s important but not the most urgent. D. Respiration rate decreases from 40 to 32 breaths/minute: This may indicate improvement or fatigue; context matters. However, it is less critical than absent breath sounds.