Background
A 68-year-old man was admitted from the emergency department with an acute exacerbation of COPD after three days of worsening shortness of breath and productive cough.
History: COPD for 9 years, hypertension. Former smoker, 40 pack-years, quit 5 years ago. Home medications: tiotropium inhaler daily, lisinopril 10 mg daily. No known allergies.