The 20-year-old patient with asthma presents to the emergency department with increased work of breathing and severe wheezing after exposure to household dust and mold. The patient used the albuterol inhaler 6 times in the previous 4 hours with minimal relief. Upon inspection, the nurse notes extensive accessory respiratory muscle use with moderate supraclavicular retractions and nasal flaring. The nurse auscultates expiratory wheezing in all lung fields. The patient is afebrile, normotensive, significantly tachypneic, and mildly tachycardic. The chest x-ray is clear. The nurse prepares to administer which medication first?