Dyspnea, cyanosis, circulatory system symptoms, digestive and urinary system symptoms, and psychoneurological symptoms will appear when diffusion function decreases. 1. Difficulty in breathing: Difficulty in breathing is the earliest symptom that appears when diffusion function decreases, which is manifested as shortness of breath after patient’s activity. 2. Cyanosis: Cyanosis can be observed in the patient’s lips, tongue and cheeks. 3. Circulatory system symptoms: rapid heartbeat and, in severe cases, drop in blood pressure. There may also be arrhythmia, in which the patient shows pain in the precordial region, weakness, and so on. 4. Digestive and urinary symptoms: nausea, vomiting, loss of appetite, oliguria and other symptoms. 5. Psycho-neurological symptoms: patients may feel irritable and restless, and have symptoms of body twitching. If the above symptoms occur, you should consult the doctor in time and take standardized treatment under the doctor’s guidance.