The purpose of this study is to explore the effectiveness of lung-protective ventilation during general anesthesia for neurosurgical procedures on postoperative pulmonary outcome, compared with traditional ventilation.

After screened for preoperative risk classification of postoperative respiratory complications,360 patients undergoing elective neurosurgery are randomly assigned to two groups, lung-protective ventilation (L) and traditional ventilation(T).Patients are mechanical ventilated with either a tidal volume of 10-12 ml/kg ideal body weight (IBW,T) or 6-8ml/kg IBW with 6-8 cm H2O PEEP(L),both with recruitment maneuver (RM).Each RM consists of applying a continuous positive airway pressure of 30 cmH2O for 30 seconds. Postoperative pulmonary complications are compared between groups.

Inclusion Criteria:

1. > 40 years ,and < 80 years
2. Scheduled for neurosurgery
3. After informed consent has been obtained
4. With an expected duration of ≥ 4 hours
5. preoperative risk index for pulmonary complications≥ 2
6. Glasgow Coma Scale >8

Exclusion Criteria:

1. Mechanical ventilation of > 1 hour within the last 2 weeks before surgery
2. Body mass index ≥ 35 kg/m2
3. Acute respiratory failure (pneumonia, acute lung injury or acute respiratory distress syndrome)
4. Emergency surgery
5. Severe cardiac disease
6. Progressive neuromuscular illness
7. Pregnancy
8. Refusal to participate