question: Q:A 59-year-old patient with COPD is admitted with difficulty breathing and increased sputum production. Approx. a week ago, he developed an upper respiratory tract infection. On admission, his blood pressure is 130/80 mm Hg, the heart rate 92/min, the respiratory rate 24/min, the temperature 37.6°C (99.7°F), and SaO2 on room air 87%. Chest radiograph shows consolidation in the lower lobe of the right lung. Arterial blood gases (ABG) are taken and antibiotics are started. A nasal cannula provides 2L of oxygen to the patient. When the ABG results arrive, the patient’s SaO2 is 93%. The results are as follows:
  pH 7.32
  PaO2 63 mm Hg
  PaCO2  57 mm Hg
  HCO3- 24 mEq/L
  What is the most appropriate next step in the management of this patient?? 
  {'A': 'Increase oxygen to SaO2 > 95%', 'B': 'Re-take the ABG and observe the patient until the results are available', 'C': 'Start non-invasive positive pressure ventilation', 'D': 'Intubate and start invasive ventilation', 'E': 'Administer oral corticosteroids'},