The principle of the sputum aspirator is to use negative pressure to draw phlegm and pus from the respiratory tract through a suction tube into a sputum reservoir. The sputum aspirator is a medical device that inserts a suction tube into the respiratory tract and sucks out secretions from the respiratory tract using negative pressure, thus keeping the respiratory tract open and preventing certain diseases and complications. The sputum aspirator can be divided into a manual sputum aspirator and an electrically operated sputum aspirator, of which the electrically operated sputum aspirator is more commonly used in the hospitals and at home, which is more convenient to use. 1. Indications: used for patients who are unable to expel secretions from the respiratory tract on their own. 2. Precautions: Install the suction tube correctly, check the sealing before use, use it gently, pay attention to the size of the negative pressure, and sterilize it for storage after use. Please use it under doctor’s instruction. 3. Adverse reactions: may cause respiratory mucosal damage bleeding. When the patient has obvious symptoms or sputum suction occurs suddenly such as cyanosis or heart rate drop, etc. Please consult a doctor promptly.