A 9-year-old girl with known asthma presents with an acute exacerbation triggered by a viral illness. She is speaking in phrases, has a respiratory rate of 28, oxygen saturation 95 percent on room air and uses accessory muscles. After three back-to-back salbutamol and ipratropium nebulisers and oral prednisone, she feels improved but still mildly short of breath. What is the most appropriate disposition?