气胸、胸腔 积液、腹腔积液等怎么就阻碍肺弹性回缩了？

Collapse may be caused by two different mechanisms.The first of these is loss of the forces opposing the elastic recoil of the lung, which then decreases in volume to the point at which airways are closed and gas is trapped behind the closed airways. The second is obstruction of airways at normal lung volume, which may be attributed to many different causes. This also results in trapping of gas behind the obstructed airway. Whatever the cause of the airway closure, there is rapid absorption of the trapped gas because the total partial pressure of gases in mixed venous blood is always less than atmospheric (see Table 25.2). This generates a subatmospheric pressure more than sufficient to overcome any force tending to hold the lung expanded.

肺萎陷的发病机制通常分为两种：一种是肺弹 性回缩的反作用力丧失，导致肺容积减少直至气道闭 合、气体陷闭；另一种是肺容量正常时，多种病因造 成的气道阻塞，这也会导致气体无法通过阻塞气道而 陷闭。无论气道闭合的病因如何，由于混合静脉血中 气体的总分压始终低于大气压，所以陷闭气体被迅速 吸收（见表25.2），在萎陷肺组织内产生的负压大于 任何尝试扩张肺的力。

Therapy depends on the physiological abnormality. Factors opposing the elastic recoil of the lung should be removed wherever possible. For example, pneumothorax, pleural effusion and ascites may be corrected. In other cases, particularly impaired integrity of the chest wall, it may be necessary to treat the patient with artificial ventilation.Reexpansion of collapsed lung often requires high pressures to be applied (page 251), but it is usually possible to restore normal lung volume.

治疗取决于生理异常，尽可能地纠正气胸、胸腔 积液、腹腔积液等阻碍肺弹性回缩的因素。在其他情 况下（特别是胸壁完整性受损时），可能需要行人工 通气治疗。肺萎陷的复张通常需要施加压给氧（见第 236页），有可能恢复正常的肺容量。

这个治疗不是反掉了吗？气胸、胸腔 积液、腹腔积液等怎么就阻碍肺弹性回缩了？应该是有利于肺弹性回缩