This study aims to explore the application of Electrical Impedance Tomography (EIT) in evaluating the effectiveness of OLE (Oscillatory Lung Expansion) airway clearance therapy for ICU patients with pulmonary infections. The goal is to understand the treatment response differences in patients with various causes of atelectasis (lung collapse). The study will include adult patients diagnosed with pulmonary infections and admitted to the ICU. The primary endpoint of the study is the peak cough flow (CPF), which measures the patient's ability to clear secretions from the lungs through coughing.

Inclusion Criteria:

1. Clearly diagnosed with pulmonary infection in the ICU, confirmed by microbiological tests (sputum culture, blood culture, etc.) or imaging tests (chest CT, chest X-ray);
2. Age ≥ 18 years;
3. Respiratory support is oxygen therapy (nasal cannula or face mask oxygen therapy);
4. Sputum volume > 30 ml/day;
5. The patient or their legal representative signs the informed consent form.

Exclusion Criteria:

1. Pregnant or breastfeeding women;
2. Presence of respiratory or circulatory failure (requiring mechanical ventilation or vasopressor support to maintain circulation);
3. Untreated tension pneumothorax;
4. Body Mass Index (BMI) exceeding 50 kg/m²;
5. Rib deformities or severe thoracic deformities;
6. Contraindications for the use of EIT (such as implanted automatic cardiac defibrillators, acute chest trauma, subcutaneous implanted pumps, etc.);
7. Early withdrawal from the study or incomplete clinical data.