The pressure of negative pressure aspiration normally requires 40-53.3kpa, and for aspiration of this condition, a negative pressure suction device is required. If the negative pressure is too high, it may increase the chance of mucosal damage, and if the negative pressure is too low, it may result in sputum not being easily aspirated, so the appropriate pressure needs to be maintained. Normally, the negative pressure during aspiration should be 40-53.3kpa, which is reasonable at this time. However, it should be noted that this pressure is not absolute and sometimes the sputum is too viscous and it may be necessary to increase the negative pressure appropriately. In addition, it should also be noted that there are some precautions to be taken during aspiration, such as the need to closely observe whether the patient has chest tightness, dyspnea and other related conditions during aspiration, and the need to monitor other vital signs to ensure the safety of aspiration.