According to the problems of traditional closed thoracic drainage in clinical work, this study aims to further improve and improve the new closed thoracic drainage system by changing the material of drainage tube, increasing the regulating valve of external fixator and increasing the gas flow monitoring kit for special patients, so as to expand its clinical application scope and formulate its operation. Standardize. At the same time, through a randomized controlled study, the simplicity, effectiveness and safety of the new minimally invasive thoracic closed drainage system developed by the research group were deeply studied.

The traditional closed thoracic drainage method has complex operation and high technical requirements. It has obvious pain during and after operation. Operational complications such as tissue organs, intercostal vessels and nerve injury may occur during the operation. Accidents may also occur after catheterization, including leakage around thoracic drainage tube, thoracic drainage tube prolapse, subcutaneous emphysema and accumulation. Liquid; To solve these problems, we have invented "minimally invasive thoracic closed drainage system" through a number of patent designs, including: thoracic closed drainage tube implantation expansion forceps, double-chamber thoracic drainage device with side balloon, guide wire, puncture needle, various types of dilators, chest tube fixation devices, etc. The system has the characteristics of minimally invasive puncture and implantation of drainage tube, safe, fast operation, no need of suture and fixation, good position of drainage tube after implantation, less pain for patients, and closing incision in the medial part of patients, avoiding leakage and subcutaneous emphysema and hydrops.

The selection criteria were as follows:

• age 18-70 years, gender is not limited;
• subjects clearly understand the purpose of the study, are willing and able to comply with the requirements to complete the study and sign the informed consent;
• 18 Kg/m2 < BMI < 25 Kg/m2;
• patients who need thoracic closed drainage for exhaust and drainage because of pneumothorax volume > 30%;
• subjects did not have serious chest wall deformities.

Exclusion criteria:

• Patients at high risk of bleeding, including patients with congenital hemophilia, thrombocytopenia (PLT < 50 *109/L), platelet dysfunction (such as idiopathic thrombocytopenic purpura, disseminated intravascular coagulation, congenital platelet dysfunction);
• Cardiopulmonary function is poor, which is not suitable for the participants.
• Patients with other infectious diseases (inflammation, tuberculosis) or empyema in the thoracic cavity;
• Infection of skin around puncture and drainage;
• Participated in other clinical trials within 30 days;
• Other reasons why the researchers think it is inappropriate to participate in the experiment.