Mechanically ventilated patients can develop a condition in which air becomes trapped within the alveoli at end-expiration; this is called auto-PEEP.
Auto-peep has several adverse effects:
Barotrauma from positive pressure trapped within the alveoli
Increased work of breathing
Worsening pulmonary gas exchange
Hemodynamic compromise secondary to increased intra-thoraic pressure
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:
Short expiration times (i.e., inadequate time for the evacuation of alveolar air at end-expiration)
Bronchoconstriction
Plugging of the bronchi (e.g., mucus or foreign body) creating a one-way valve and air-trapping
Auto-PEEP may be treated by:
Reducing tidal volume
Reducing the respiratory rate
Decreasing inspiratory time
Increasing PEEP
Patients may need to be heavily sedated to accomplish the above ventilator maneuvers.
References
Follow me on Twtitter (@criticalcarenow) or Google+ (+criticalcarenow)
