The steps of oxygen intake are to connect the flow meter, humidification bottle, and oxygen tube, then turn on the oxygen intake device, adjust the flow of oxygen intake, test the oxygen tube to see if it is smooth, and finally connect the patient to oxygen therapy through a nasal catheter or face mask. The first step of oxygen intake is to connect the oxygen intake device correctly, including the flow meter, humidification bottle and oxygen tube, etc. After connecting the device, you need to turn on the oxygen intake device, which may be the device for central oxygen supply or the oxygen cylinder. Finally, you need to adjust the flow rate of oxygen according to the condition, and you need to test whether the oxygen tube is smooth, for example, you can put the end of the oxygen tube into saline to see whether there are air bubbles overflow. If everything is normal, oxygen can be administered to the patient, and the oxygen tube or oxygen mask should be fixed. In addition, the patient should be tested the effect of oxygenation, if the patient’s chest tightness improves, the cyanosis of lips reduces or disappears, and the oxygen saturation level rises to more than 90%, it means that oxygen therapy is effective, and it is necessary to adjust the flow rate of inhaled oxygen according to the situation. Severe cases may require the use of non-invasive ventilator, or even tracheal intubation, invasive mechanical ventilation, and also need to be actively dealt with for the cause of the disease.