Due to excessive sputum in the airway, excessive sputum in the airway is sucked out through the negative pressure suction device. The negative pressure for adult aspiration is between 40-53.5kPa, which can promote the patient to discharge a large amount of sputum, prevent the airway from blockage, promote the relief of airway inflammation, and also keep the airway open to prevent the occurrence of aspiration pneumonia and asphyxia. When using the suction machine, pay attention to test suction with physiological saline to check whether the passage is smooth, pay close attention to the index of the pressure gauge to keep it stable and prevent the abdominal pressure from being too large or too small. When aspirating, lift the suction tube from deep upward, rotate it left and right to absorb the sputum, adjust the suction pressure according to the amount of sputum and the patient’s response, and do not exceed 15 seconds each time when aspirating sputum.