Clinical Study of the Effect of Methylprednisolone Combined

Inclusion Criteria: * 1\. After fully understanding the purpose and significance of the trial, the patients voluntarily participated in the trial and signed the informed consent; 2\. The type of operation was general anesthesia and thoracoscopic lobectomy; 3\. Age 18-75 years old, including boundary value, gender is not limited; 4\. BMI 18-26kg / m2; 5\. ASA grade I-II; no mental disorder, normal consciousness, normal communication; 6\. No contraindications of methylprednisolone and dihydroxypropyltheophylline. Exclusion Criteria: * 1\. There were diseases of immune, endocrine, nervous and mental system before operation, and serious dysfunction of heart, liver and kidney; 2\. Take immunosuppressive drugs and non steroidal anti-inflammatory drugs before operation; 3\. Respiratory tract infection (cough, expectoration, suffocation, etc.) in recent 1 month; pneumonia, bronchitis, etc. on CT; 4\. History of chronic pulmonary disease, including but not limited to asthma, pulmonary abscess, tuberculosis, chronic bronchitis, etc; 5\. FEV1 \< 50%; 6\. Oxygen saturation was lower than 90% and airway pressure was higher than 40 cm H20; 7\. Continuous hypotension or hypertension during the operation; intraoperative blood loss \> 1000ml; 8\. Allergic to methylprednisolone or dihydroxypropyltheophylline; 9\. There are any other situations that the researchers think are not suitable for inclusion.