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

The goal of this clinical trial is to evaluate the safety and efficacy of sodium bicarbonate pleural lavage in treating complex pleural effusion in adult. The main questions it aims to answer are: Will sodium bicarbonate pleural lavage reduce the failure rate of medical treatment (referral rate for surgery) for complicated pleural effusion？ Can sodium bicarbonate pleural lavage accelerating the rehabilitation of patients with complicated pleural effusion？ Will sodium bicarbonate pleural lavage improve the prognosis of patients with complicated pleural effusion? Participants will will undergo catheter placement for continuous drainage of pleural effusion. Once at least 200 mL of pleural effusion has been drained: Group A: Participants will receive a daily intrapleural injection of 200 mL of saline in 7 days; Group B: Participants will receive a daily intrapleural injection of 200 mL of 2.5% sodium bicarbonate in 7 days.