In three groups, the plasma ET 1 concentration at 0 h after CPB was significantly higher than that at 24 h pre operation, and the plasma NO concentration at 0 h after CPB was significantly lower than that at 24 h pre operation.

• CPB后即刻 3组血浆ET 1水平明显高于术前 ；NO水平明显低于术前(分别P <0 0 5、P <0 0 1)。