Searching for the optimal positive end-expiratory pressure for lung protective ventilation

Purpose of reviewThe optimal strategy for setting positive end-expiratory pressure (PEEP) has not been established. This review examines different approaches for setting PEEP to achieve lung-protective ventilation.Recent findingsPEEP titration strategies commonly focus either on achieving adequate arterial oxygenation or reducing ventilator-induced lung injury from repetitive alveolar opening and closing, referred to as the open lung approach. Five recent trials of higher versus lower PEEP have not shown benefit with higher PEEP, and one of the five trials showed increased harm for patients treated with the open lung strategy. Evidence suggests that some patients may respond beneficially to higher PEEP by recruiting lung, whereas other patients do not recruit lung and merely overdistend previously open alveoli when higher PEEP is applied. A PEEP titration approach that differentiates PEEP responders from nonresponders and provides higher or lower PEEP accordingly has not been prospectively tested.SummaryWhen compared, no method for setting PEEP has been proven superior to another. Based on recent studies, higher compared with lower PEEP has not improved clinical outcomes and worsened mortality in one study. Future research should focus on identifying feasible methods for assessing lung recruitability in response to PEEP to enrich future trials of PEEP strategies.