Manual airway aspiration is a task performed by a nurse or caregiver and if the nursing/care work is overloaded, it has the disadvantage that airway aspiration cannot be performed an appropriate number of times according to the needs of the patient. Therefore, an electric phlegm suction system that can compensate for the shortcomings has been developed. The purpose of this clinical trial is to compare and evaluate the efficacy and safety of the test device by applying the unmanned electric phlegm suction system procedure using an investigational device (LMECA.A1000) and the conventional manual airway aspiration procedure to the patients who received mechanical ventilation through the artificial airway in this clinical trial.

Inclusion Criteria:

• Those aged ≥19 among the in-patients in the intensive care unit of the study site.
• Patients who have been applied with mechanical ventilation through the artificial airway such as tracheal intubation or tracheotomy and have maintained PaO2/FiO2 values above 100mmHg.
• Patients whose application time of mechanical ventilation does not exceed 36 hours
• Those who are expected to see continued application of mechanical ventilation for at least 72 hours after participating in this study

Exclusion Criteria:

• The subject or a legally acceptable representative refuses to participate in the study
• Those who have become pregnant or are planning to become pregnant during the study period
• Patients who need to maintain their plateau pressure with the mechanical ventilation setting of FiO2 exceeding 80% or exceeding Pplat of 30cmH2O.
• Patients with severely lowered immune function such as advanced hematologic malignancy, bone marrow transplantation failure, agranulocytosis, and absolute neutrophil count (ANC) of <500/mm3
• Those with unstable cardiovascular conditions such as arrhythmia accompanied by hemodynamic instability and severe hypoxemia
• Those who continue to bleed due to hemorrhagic causes, including multiple traumas or thrombocytopenia
• If the patient is scheduled for or had performed a solid organ transportation on the day of study participation, or self-recovered through cardiopulmonary resuscitation (CPR)
• Patients with pulmonary disease accompanied by hemoptysis
• In addition, if the medical staff decides that it is not appropriate to apply the investigational device to the subject or perform bronchoscopy