SpO2 is the English abbreviation for pulse oximetry, and its normal value is 90-100%. If SpO2 is less than 90%, it is generally considered that hypoxemia occurs, or even type I respiratory failure, which will bring a serious threat to the patient’s life, and it is necessary to correct hypoxemia as early as possible, increase the concentration of inspired oxygen and the oxygen flow rate, and correct hypoxia and type I respiratory failure as soon as possible. If the SpO2 concentration is close to 100%, the oxygen saturation is considered to be relatively normal, or even too high, the oxygen concentration can be appropriately reduced to minimize the occurrence of type II respiratory failure caused by too much oxygen. Because oxygen hypoxia state after correction if continued to give oxygen, high concentration of oxygen will lead to carbon dioxide and other synchronous rise in the occurrence of pulmonary encephalopathy, to the patient’s life will also bring danger.SpO2 pulse oximetry monitoring is very convenient, easy to operate, with the arterial blood gas analysis is more effective in guiding the clinician’s medication and ventilator parameters of the adjustment.