The infоrmаtiоn belоw wаs obtаined from a pulmonary function report for a 40-year-old male who weighs 73 kg (161 lb) and is 177 cm (5 ft 9 in) tall:FEV1 2.16 L (53% of predicted)FVC 2.50 L (55% of predicted)FEV1/FVC 90%DLCO 51% of predicted There is no response to bronchodilator therapy. Which of the following should a respiratory therapist recommend NEXT?