Ⅱ型呼吸衰竭时血气变化应为

A．{{*HTML*}}PaO<SUB>2</SUB>＜60mmHg，PaCO<SUB>2</SUB>＞50mmHg
B．{{*HTML*}}PaO<SUB>2</SUB>＞60mmHg，PaCO<SUB>2</SUB>＜50mmHg
C．{{*HTML*}}PaO<SUB>2</SUB>＞50mmHg，PaCO<SUB>2</SUB>＞60mmHg
D．{{*HTML*}}PaO<SUB>2</SUB>＜70mmHg，PaCO<SUB>2</SUB>＞50mmHg
E．{{*HTML*}}PaO<SUB>2</SUB>＜60mmHg，PaCO<SUB>2</SUB>＜50mmHg