Chronic obstructive pulmonary disease usually does not develop into fibrosis because it is a ventilation dysfunction disease, mainly because of the damage of the large airways, while interstitial lung disease is a diffusion dysfunction, which is a problem of oxygen intake and blood exchange, so chronic obstructive pulmonary disease should not develop into fibrosis. The complication of chronic obstructive pulmonary disease is mainly due to the lack of oxygen and the failure to expel carbon dioxide, so after a long period of chronic obstructive pulmonary disease, pulmonary heart disease may appear. Because of the increased resistance of the right heart, pulmonary heart disease may occur, and over time it may lead to respiratory failure, which means that oxygen cannot be absorbed and carbon dioxide cannot be expelled, so there will be general edema, bulbar edema and other signs of respiratory failure.