The most common cause of increased carbon dioxide concentration in the blood is various chronic obstructive pulmonary diseases, resulting in respiratory ventilation dysfunction, which cannot adequately expel the carbon dioxide produced by the body, resulting in carbon dioxide storage and thus increased carbon dioxide concentration. The common symptoms of increased carbon dioxide concentration are: a. Symptoms of dyspnea. Patients show difficulty in breathing, shortness of breath, also accompanied by chest tightness, panic and a series of symptoms. Second, the nervous system symptoms, due to carbon dioxide storage, carbon dioxide concentration increases, the human central nervous system will have a certain inhibitory effect, the higher the concentration of carbon dioxide, the more obvious the inhibitory effect on the respiratory center, sometimes there will be respiratory arrest. The higher the concentration of carbon dioxide, the more pronounced the suppression of the respiratory center, and sometimes respiratory arrest.