Title: Don't Fall Asleep on Auto-PEEP
题目：不要小看内源性呼气末正压（auto－PEEP）
Author 作者: Haney Mallemat

Mechanically ventilated patients can develop a condition in which air becomes trapped within the alveoli at end-expiration; this is called auto-PEEP.
机械通气的病人会造成肺泡气体在呼气末压的储留，这一现象称为内源性呼气末正压。
Auto-peep has several adverse effects:
内源性呼气末正压有几个副作用：
Barotrauma from positive pressure trapped within the alveoli 
由肺泡内产生的正压力造成的压力损伤
Increased work of breathing
增加呼吸负荷
Worsening pulmonary gas exchange
肺气体交换阻力的增加
Hemodynamic compromise secondary to increased intra-thoraic pressure
由胸内压的增加所造成的血液动力学紊乱

Auto-PEEP classically occurs in intubated patients with asthma or emphysema, but it may also occur in the absence of such disease. The risk of auto-PEEP is increased in patients with:
内源性呼气末正压通常在机械通气的哮喘或肺气肿病人中发生，但没有这些情况时也会出现。内源性呼气末正压产生的危险与下列因素有关：
Short expiration times (i.e., inadequate time for the evacuation of alveolar air at end-expiration)
呼气时间短，没有足够的时间将呼吸末期肺泡内气体清除
Bronchoconstriction 支气管痉挛
Plugging of the bronchi (e.g., mucus or foreign body) creating a one-way valve and air-trapping
支气管栓子形成（如粘液或异物），导致单项版模，气体滞留

Auto-PEEP may be treated by:
内源性呼气末正压的治疗办法：
Reducing tidal volume 降低潮气量
Reducing the respiratory rate 减少呼吸频率
Decreasing inspiratory time 缩短吸气时间
Increasing PEEP 增加PEEP

Patients may need to be heavily sedated to accomplish the above ventilator maneuvers.
为达到如上的指标，可能需要对病人进行深度镇静。