Problem: A 65-year-old man presents with a 6-month history of dyspnea and "noisy breathing." He has also noticed a limitation in his exercise tolerance because of dyspnea. He was a smoker of 38 pack-years. On examination, he has "noisy breathing" audible without a stethoscope, particularly during inspiration. On auscultation, there is a generalized decrease in breath sounds, without any focal findings. Pulmonary function tests show a normal FEV1 and FVC. Flow-volume curve demonstrates a flattening of the inspiratory portion of the curve. The expiratory portion of the curve appears normal. The most likely pathophysiologic explanation for the findings is: Decreased elastic recoil of the lung Fixed upper airway obstruction Increased elastic recoil of the lung Variable intrathoracic upper airway obstruction Variable extrathoracic upper airway obstruction. Need Assignment Help?