本研究的目的是阐明胸穿抽液后胸腔压力变化导致肺功能改善的关系。胸穿常选第8～9肋间隙为穿刺点,用 U 型水柱测压计测胸腔压力,胸腔压力是指吸气与呼气时胸腔压力的均数。测压时间为初始及每抽400ml 液体后。出现以下情况时即停止抽液:胸腔压力<-20cm H_2O;出现中度以上胸痛、咳嗽、气短或者再抽不出液体。病人均能配合作好肺功能检 The purpose of this study is to elucidate the relationship between thoracic pressure changes and pulmonary function after thoracentesis. Chest wear often choose the first 8 to 9 intercostal space for the puncture point, with U-shaped hydrostatic pressure measurement chest pressure, chest pressure refers to the average number of chest pressure during inspiration and expiration. Pressure measurement time for the initial and each pumping 400ml liquid. Stop pumping when: chest pressure <-20cm H_2O; moderate chest pain, cough, shortness of breath or no more liquid. Patients can cooperate for pulmonary function test