A、PaO<sub>2</sub>＜50mmHg和（或）PaCO<sub>2</sub>＞50mmHg
B、PaO<sub>2</sub>＜50mmHg和（或）PaCO<sub>2</sub>＞60mmHg
C、PaO<sub>2</sub>＜60mmHg和（或）PaCO<sub>2</sub>＞50mmHg
D、PaO<sub>2</sub>＜60mmHg和（或）PaCO<sub>2</sub>＞80mmHg
E、PaO<sub>2</sub>＜70mmHg和（或）PaCO<sub>2</sub>＞50mmHg