Review Question - QID 104904

A 67-year-old female presents to the emergency room with dry cough and malaise. She has no other complaints. She has a past medical history of a meningioma status post resection. Her vital signs are T 100.4 F (38 C), O2 93% on room air, RR 20, BP 115/75 mmHg. Physical examination is notable for crackles bilaterally. A chest radiograph is obtained (Image A). The patient is admitted and initially treated guideline-compliant antibiotics for community-acquired pneumonia. Unfortunately, her respiratory function deteriorates. An arterial blood gas is drawn. On room air at sea level, PaO2 is 71 mmHg and PaCO2 is 34 mmHg. Induced sputum samples reveal organisms on methenamine silver stain. What is the best treatment strategy for this patient?