A 95-year-old female pres...

A 95-year-old female presented with a 4-week history of dyspnea and dry cough. She had not previously reported these symptoms to her doctor. For the past 6 months, she has been taking nitrofurantoin daily to prevent recurrent urinary tract infections. Her oxygen saturation was 83% on room air. Physical examination showed inspiratory crackles in the upper lung fields but no jugular venous distention or edema. Laboratory studies showed neutrophilic leukocytosis but no eosinophilia or elevations in aminotransferase levels. A sputum culture and viral respiratory panel were negative. Chest radiograph and computed tomography of the chest are shown. What is the most important element of the management of this condition?