There are two cases in which the cross-sectional area of the tracheal catheter balloon does not match the cross-sectional area of the patient's airway. If the area of the tracheal catheter balloon is smaller than the cross-sectional area of the patient's airway, the pressure in the balloon reaches 30 cmH2O, and the airway cannot be completely sealed; This will increase the risk of VAP. If the area of the tracheal catheter balloon is significantly larger than the cross-sectional area of the patient's airway, and the pressure in the balloon reaches 30 cmH2O, the airway cannot be effectively sealed; The formation of wrinkles around the airbag also increases the risk of VAP in patients. Therefore, the purpose of this study is to build a risk model of airway leakage of patients' endotracheal tubes, which provides an accurate and objective assessment tool for medical staff, so that medical staff can select the endotracheal tubes purposefully and with emphasis from the beginning of the patients' endotracheal tubes, and reduce the airway leakage or airway mucosal damage of the endotracheal tubes.

Admission number, department, name, gender, height, and weight are obtained through the hospital's electronic medical record management system。 Tidal volume (set Tidal volume), airway peak pressure (real-time data on the ventilator screen), data collection is synchronized with the minimum cuff pressure measurement when the airway is closed.

Inclusion Criteria:

Invasive mechanical ventilation; Chest CT imaging examination within 1 year;

Exclusion Criteria:

Patients with pneumothorax Acute respiratory distress syndrome; Chronic Obstructive Pulmonary Disease; Multiple organ dysfunction.

The investigators selected mechanical ventilation patients admitted to the Extracardiac and Respiratory Care Units of Nantong University Affiliated Hospital from September 2021 to September 2022 who underwent cardiac, pulmonary, esophageal surgery, and other procedures as the research subjects.