Efficacy and Safety of Intrapulmonary Percussive Ventilation in Patients With Pulmonary Infection Receiving Invasive Mechanical Ventilation

The goal of this clinical trial is to learn whether adding intrapulmonary percussion ventilation (IPV) to standard airway clearance treatment improves clinical outcomes in invasively mechanically ventilated patients with pulmonary infection. It will also evaluate the safety of IPV in this population and assess changes in lung ventilation using electrical impedance tomography (EIT). The main questions it aims to answer are: Does adding IPV shorten the duration of invasive mechanical ventilation compared with standard therapy alone? Does IPV improve regional and global lung ventilation? Does IPV improve clinical indicators, including oxygenation, lung mechanics, and pulmonary infection scores? Is IPV safe in mechanically ventilated patients with pulmonary infection? Participants will: Receive either standard therapy alone or standard therapy plus IPV Undergo serial EIT monitoring at predefined time points Receive routine clinical assessments and ventilator parameter monitoring during ICU stay Be followed until successful weaning, discharge, or completion of hospitalization

Inclusion Criteria: 1. Age ≥ 18 years; 2. Meeting the diagnostic criteria for pulmonary infection, defined as follows: meeting the diagnostic criteria for hospital-acquired pneumonia (HAP) or ventilator-associated pneumonia (VAP) according to the Chinese Guidelines for the Diagnosis and Treatment of Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia in Adults (2018 edition), or meeting the diagnostic criteria for community-acquired pneumonia (CAP) according to the Chinese Guidelines for the Diagnosis and Treatment of Community-Acquired Pneumonia in Adults (2016 edition); 3. Oxygenation index (PaO₂/FiO₂) ≤ 300; 4. Currently receiving invasive mechanical ventilation, with no planned liberation from invasive mechanical ventilation within the next 24 hours; 5. Receiving analgesia and sedation; 6. Written informed consent provided by the patient's family member or legally authorized representative. Exclusion Criteria: 1. Presence of severe hemodynamic instability (norepinephrine dose \> 0.5 μg/kg/min); 2. Markedly elevated intracranial pressure (\> 25 mmHg) or a condition requiring strict intracranial pressure control; 3. Severe pulmonary bullae, untreated tension pneumothorax or undrained mediastinal emphysema; 4. Unstable chest wall, flail chest, recent thoracic or airway surgery, or severe thoracic spine injury; 5. Active massive hemoptysis; 6. Severe bronchospasm or inability to tolerate fluctuations in airway pressure; 7. Inability to place the EIT chest belt, such as open thoracic surgical wounds or skin lesions at the belt placement site; 8. Receiving extracorporeal membrane oxygenation (ECMO); 9. Acute exacerbation of chronic obstructive pulmonary disease as the primary reason for the current episode of invasive mechanical ventilation; 10. Expected death within 24 hours, or a decision already made to withhold or withdraw life-sustaining treatment; 11. Pregnancy or breastfeeding; 12. Concurrent participation in another clinical trial.