Effectiveness and Safety of Sodium Bicarbonate Pleural Lavage in the Treatment of Complex Pleural Effusion

Inclusion Criteria: * Hospitalized patients aged 18 to 80 years, inclusive. * Patients fulfilling any one of the following three criteria for complicated pleural effusion: A. Pleural fluid pH \< 7.2; B. Pleural fluid glucose \< 2.2 mmol/L and LDH \> 1000 IU/L; C. Positive pleural fluid culture or smear for pathogens. * Pleural effusion volume exceeding 300 mL, as determined by CT imaging using the formula D\^2 \* L (where D represents the maximum depth and L the maximum length), and for whom pleural effusion drainage is clinically indicated according to established guidelines or criteria. Exclusion Criteria: * Patients with known allergies to sodium bicarbonate or normal saline. * Patients with severe coagulation disorders. * Patients with severe heart or kidney failure. * Pregnant or lactating women. * Patients with pleural effusion caused by hospital-acquired interference, tuberculosis, fungal infections, or non-infectious causes. * Patients unable to tolerate intrapleural administration. * Patients with chronic lung diseases that may affect antibiotic efficacy, such as uncontrolled chronic obstructive pulmonary disease (COPD GOLD E group), bronchiectasis, or immunodeficiency. * Patients who have experienced shock, major bleeding, trauma, or pulmonary surgery within the past 5 days. * Patients with a history of lung or pleural surgery on the side of the pleural effusion. * Patients who have recently had chest tubes placed due to pneumothorax, surgery, or pleural effusion. * Patients currently enrolled in another drug or device clinical trial. * Patients with poor compliance or difficulty in follow-up, or those with an expected survival of less than 3 months due to conditions other than pleural effusion.