At 11 p.m., a male client is admitted to the emergency department. He has a respiratory rate of 44 breaths/minute. He’s anxious, and wheezes are audible. The client is immediately given oxygen by face mask and methylprednisolone (Depo-medrol) I.V. At 11:30 p.m., the client’s arterial blood oxygen saturation is 86% and he’s still wheezing. The nurse should plan to administer: