A 57-year-old patient complains of constant shortness of breath, which worsens during physical activity exertion, unproductive cough. more often in the morning. He has been ill for 12 years. Smokes over 40 years (20 cigarettes per day). From the anamnesis, it is known that he suffers from inflammation lungs Objectively observed: temperature 36.5 C, heart rate 22 per minute, pulse 80 bpm, blood pressure -140/80 mm Hg. art, cyanosis of the lips, over the lungs weakened vesicular breathing, a large number of scattered dry rales. Changes in which spirometric indicator most likely to indicate the pathophysiological mechanism of the patient's respiratory failure?