1. Connect the rubber hose of the oxygen bag filled with oxygen to the sterilized nasal catheter, and put the other end of the nasal catheter into a cup filled with cold boiled water.

2. Clean a nasal cavity with a cotton swab dipped in cold boiled water, insert the nasal catheter with oxygen moistened by cold boiled water into the nostril, and pay attention to fixing the nasal catheter on the edge of the nostril with adhesive tape to prevent slippage.

3. The oxygen bag hose is closely connected with the nasal catheter. Open the screw clamp and align the mouth end of the nasal catheter with the cheek.