A 65-year-old male presented to the OPD with progressive dyspnea on exeion for 3 months. Patient records told that he had an episode of necrotizing pancreatitis along with ARDS in the past for which he was mechanically ventilated for a long time. Patient is a chronic smoker. On examination, low pitched inspiratory and expiratory wheeze is heard over mid-chest area. PFTs revealed, FEV1 is 78% of predicted. FEV1/FVC ratio is 60%. Flow volume curve is given. What is the most likely diagnosis in the above case: -
COPD Subglottic stenosis Idiopathic pulmonary fibrosis Unilateral vocal cord paralysis