A 71-year-old patient presents for a hospital follow-up visit after a recent inpatient stay for an exacerbation of COPD, the fourth such stay in the past year. The patient's home medication regimen includes albuterol/ipratropium by inhaler, theophylline, and extended release guaifenesin. The latest FEV1 value in a one-second test was 40% of the predicted value; o2 Sat was 90%. Which of the following is the most appropriate management strategy for this patient?