Question

A 5-month-old female infant is brought to a primary care clinic by her parents due to rapid breathing and poor feeding. She developed nasal congestion and a mild cough three days ago. Over the past 24 hours, the cough has deepened, and she has consumed only one-third of her usual breast milk volume. She was born at term, and her immunizations are up to date. Vital signs show a temperature of $37.7^\circ\text{C}$ ($99.9^\circ\text{F}$), a heart rate of $165/\text{min}$, and a respiratory rate of $68/\text{min}$. Room air pulse oximetry demonstrates an oxygen saturation of $88\%$. Physical examination reveals an irritable infant with prominent nasal flaring and significant subcostal retractions. Chest auscultation reveals diffuse fine crackles and scattered expiratory wheezes throughout both lung fields. The physician arranges for immediate transfer to the pediatric emergency department. Which of the following interventions are appropriate in the initial management of this patient? (Select all that apply)