Ventilator - Induced Lung Injury

By Neil R. MacIntyre, MD, FCCP

The Role of Cyclical Alveolar Collapse

As noted above, it has been known for several decades that cyclical alveolar collapse can potentiate (or produce) VILI.^4,24,49,50 In recent years, the term atelectrauma has been coined to describe this.¹⁵ Physically, there is a shear stress injury that occurs when a collapsed alveolar stucture "pops open," especially if adjacent to alveolar units with different mechanical properties. Cytokine release and both local and systemic injury occur as in overdistention injury. Levels of positive end-expiratory pressure (PEEP) that prevent collapse in expiration ameliorate this injury.^4,24,49-52 In one clinical trial,²⁶ a strategy utilizing both low tidal volume and high PEEP had better outcomes compared with a standard ventilator strategy.

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