The ED nurse is examining a 19-month-old boy with respiratory distress. The child’s mother reports that he has had a temperature of 101°F (38.3°C), fatigue, and hoarseness for the past 2 days, during which time the hoarseness and fatigue have progressively increased. The patient developed a barkingcough during the night. The physician diagnoses laryngotracheobronchitis (croup). The nurse knows that management of a child with croup is primarily directed toward: