You have a 7-year-old male patient who presents with a 3-day history of fever and cough productive of a thick whitish brown sputum. The patient’s lung sounds are ronchi over the right lower lung field with scattered wheezing. Vital signs are HR: 142, RR: 28, BP: 98/56, T: 102.9, SpO2: 94% on room air and 98% on 4 LPM O2 via nasal cannula. The child is alert but sleepy and is sitting up and answering questions appropriately. You have the child on the O2, and it is well tolerated. The next most appropriate treatment for this patient is: