Maximal expiratory flow volume (MEFV curve) in idiopathic pulmonary fibrosis

A: shown are the MEFV curves at presentation in a 42-year old nonsmoking man with a normal chest roentgenogram and lung biopsy-proven idiopathic pulmonary fibrosis. The FEV1 and FVC values are low relative to the predicted values, but the FEV1 to FVC ratio is increased. However, at any given lung volume, the flow rates are higher than expected because of elevated driving pressure due to an increased elastic recoil. B: shows the MEFV curve for a patient with chronic obstructive lung disease. The FEV1 and FVC values are low relative to the predicted values, and the lung volumes are increased.