脑静脉血氧分压低于何值时可出现意识丧失?

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问题: 脑静脉血氧分压低于何值时可出现意识丧失?

A: 5.33kPa(40mmHg)

B:4.53kPa(34mmHg)

C:3.73kPa(28mmHg)

D:2.53kPa(19mmHg)

E:1.60kPa(12mmHg)