1. The performance of hypoxia: after oxygen therapy, the patient’s heart rate slowed down, breathing rate decreased, blood pressure increased and stabilized, dyspnea improved, peripheral circulation changed, skin redness and warming, cyanosis reduced or disappeared, urine output increased, etc. It indicates that the oxygen therapy is effective, otherwise it indicates that the condition has deteriorated, and the oxygen therapy has not achieved the effect.

2. Blood laboratory examination: hemoglobin content, red blood cell count, hematocrit all indicate improvement or correction of hypoxia. It indicates that oxygen therapy is effective, and the treatment can be stopped. Otherwise, oxygen should be continued and actively search for other reasons.

3. Monitor Blood oxygen saturation (Sa02) : The blood oxygen saturation gradually rises after sunset, and oxygen can be suspended when it is close to normal.

4. Monitor Arterial blood gas (ABG) : Arterial blood gas is currently the most accurate and reliable method for evaluating the effect of oxygen therapy. Arterial blood gas can provide various oxygenation and metabolism parameters such as Pa02, PaCO2,  pH and so on. The increase of Pa02 is the most direct reflection of the effect of pigments. index. Insufficiency of arterial blood gas requires repeated blood draws and cannot be continuously detected in real time, but as long as the arterial blood gas check Pa02 rises, the improvement of hypoxia can be accurately judged. If it is close to normal, oxygen inhalation can be suspended, otherwise oxygen inhalation should be continued.