The relationship among preoperative partial pressure of oxygen in arterial blood ( PaO2) ,lung function index and PPC were analysed using SPSS statistics software.

• 利用SPSS11.；12统计软件；对术前动脉血氧分压(PaO_2)和肺功能指标与术后机械通气(MV)时间的关系进行多元相关分析。