What are the beneficial effects of positive end-expiratory pressure (PEEP) in mechanical ventilation?

Updated: Apr 07, 2020
  • Author: Allon Amitai, MD; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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Positive end-expiratory pressure (PEEP) has several beneficial effects and, when used at optimal levels in combination with low tidal volumes, may reduce the incidence of ventilator-induced lung injury. In particular, there is a significant amount of ongoing research evaluating the use of high levels of PEEP in acute lung injury (ALI) and ARDS. PEEP has been found to reduce the risk of atelectasis trauma by increasing the number of "open" alveoli participating in ventilation, thereby minimizing trauma due to the cyclical collapse and reopening of alveoli. However, note that in disease states such as ARDS, the degree to which alveoli function has been compromised varies tremendously within the lungs and there is no single ideal PEEP appropriate for all alveoli; rather, a compromise PEEP must be selected.

In addition to alveolar recruitment, an additional beneficial effect of PEEP is to shift lung water from the alveoli to the perivascular interstitial space. It does not decrease the total amount of extravascular lung water. This is of clear benefit in cases of cardiogenic as well as noncardiogenic pulmonary edema. An additional benefit of PEEP in cases of CHF is to decrease venous return to the right side of the heart by increasing intrathoracic pressure.

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