Low blood oxygen will show different aspects of cyanosis, central nervous system, cardiovascular system, respiratory system, etc. It can be treated with drugs such as phosphodiesterase. 1. Manifestations of low blood oxygen. (1) Cyanosis: the skin and mucous membranes can have different degrees of cyanosis. (2) Central nervous system: manifested as attention disorder, agitation, delirium, ataxia, etc. (3) Cardiovascular system: manifestations such as cardiac arrhythmia, ventricular arrest, decreased blood pressure, shock, right heart failure, etc. (4) Respiratory system: manifested by deepening and accelerating respiration. (5) Blood system: long-term hypoxia leads to secondary erythrocytosis, elevated hemoglobin and so on. 2. Treatment drugs include phosphodiesterase inhibitors such as aminophylline, anticholinergics such as atropine, etc. to relax airway smooth muscle, inhibit the release of histamine, relieve bronchial spasm, and ventilator-assisted respiration if necessary. If you have symptoms, we recommend that you consult a doctor and take the medication as prescribed by the doctor.