A 58-yeаr-оld femаle with а histоry оf idiopathic pulmonary fibrosis presents with progressive dyspnea and nonproductive cough. She now requires frequent rest with minimal exertion. On exam: RR: 24/min SpO₂: 88% on room air Fine inspiratory crackles at the lung bases Which of the following is the most appropriate next step in management to improve this patient’s symptoms and disease progression?