Acute Exacerbations of Chronic Obstructive Pulmonary Disease

A 68-year-old former heavy smoker with a history of chronic obstructive pulmonary disease presents to the emergency room with a two-day history of worsened dyspnea and increased purulence and volume of phlegm. Chest radiography shows hyperinflation and no acute infiltrates. Measurement of arterial blood gases while the patient is breathing ambient air shows acute respiratory acidosis. How should this patient be treated?