Surgical trauma is characterized by a tightly integrated sequence of neurohumoral and immunological processes. When this is marked, it can manifest as a clinical entity called the systemic inflammatory response syndrome. Previous studies reported that inflammatory milieu in the postoperative period can be a harmful and potentially modifiable condition that may affect postoperative recovery, which includes the level of pain, fatigue, dizziness, nausea and vomiting (PONV), muscle weakness, and sleep quality and then increases the need for hospitalization. The effect of postoperative inflammation-related immune suppression such as the T-cell exhaustion and lymphocyte anergy may render the patient vulnerable to both infection and the recurrence of malignancy on postoperative infection risk and malignancy recurrence are currently subjects of intense speculation and investigation.

Glucocorticoids are well known for their analgesic, anti-inflammatory, immunosuppressive agents and antiemetic effects. Though previous studies' results on postoperative outcome have been positive and in favor of glucocorticoid use, with postoperative nausea and vomiting and pain outcome parameters most significantly improved. However, high-dose methylprednisolone treatment could result in decreases T-cells postoperatively. Based on these consideration, the aim of our study was to assess the effect of a single low-dose preoperative methylprednisolone (MP) 1 mg/Kg i.v. on postoperative pain and immune functions in patients undergoing video-assisted thoracoscopic surgery (VATS) under general anesthesia.

The eighty-one patients were randomly assigned either to the MP Group or the Control Group in a 1:1 ratio using a computer-generated randomization number sequence. The group assignment was sealed in sequentially numbered opaque envelopes. No stratification or block randomization was made. The envelopes were opened on the morning of surgery, and the trial drug was prepared by a senior anaesthetist not otherwise involved in data collection. The MP group received a single-dose of MP, 1 mg/Kg i.v. (Solu-Medrolw; Pfizer, Ballerup, Denmark) and the Control group a single-dose of isotonic saline ( equal capacity with MP) i.v. The test solution was administered just 30 mins before the operation. The patients, attending anesthesiologists, surgeons, and data collectors were all blinded to patient group assignment.The primary outcomes of the levels of T lymphocyte subsets of CD3+, CD4+, and CD8+, and the CD4+/CD8+ ratio were measured at T0, T1, and T2. Postoperative pain scores were evaluated by the visual analog scale (VAS) score16, where 0 indicates painlessness, and 10 indicates severe pain. The patients were asked to evaluate their pain at rest and during coughing at 2, 4, 6, and 24 hours postoperatively. Total pump press numbers of PCA and adverse effects during 24 hours after surgery such as hypotension, bradycardia, nausea and vomiting, and dizzy were recorded and treated accordingly.

Inclusion Criteria:

• ASA Ⅱ～Ⅲ
• aged 65-85years
• consciousness,with no psychological or communication disorders, with educational level above primary school (including primary school).
• with no chemotherapy or radiotherapy before admission.
• no history of medicine allergy.
• no evident abnormality of liver, kidney or nervous system
• scheduled for radical operation for lung cancer under general anesthesia

Exclusion Criteria:

• diagnosed with diseases in nervous system or psychological disorder, history of taking sedatives or anti-depressants.
• history of hypertension, diabetes, coronary heart disease, cerebral infarction.
• had drugs which affect immunological function before.
• severe acuity or vision dysfunction or have difficulty in communication.
• with special complications during surgery.
• had blood transfusion treatment during perioperation period history of heart operation
• Mini-mental State Examination Scores less than 25 before surgery.