Aspiration is used to remove secretions or foreign bodies from the respiratory tract through the oral, nasal or artificial airway to ensure the smooth flow of the respiratory tract, and has indications and contraindications. The indications for aspiration are mainly for critically ill, elderly, comatose patients, and patients after general anesthesia surgery. In case of inability to cough or weak coughing, inability to cough up secretions, sputum or vomit from the airway by oneself, and easy breathing difficulties. Patients in emergency situations of asphyxia, such as drowning and inhalation of various foreign bodies, etc. can be aspirated. The main contraindications to aspiration are obvious skull base fractures, which prohibit the use of nasal catheters for aspiration, and serious bronchial ruptures and injuries.