Repeated applications of tidal energy inflict lung damage (VILI) when stress and strain exceed the limits of tissue tolerance.

Inflation work and energy are the products of pressure and volume, which are loosely associated with stress and strain, respectively.

Three major pressure components contribute to tidal inflation energy: flow resistive pressure, tidal elastic (driving) pressure, and the static elastic pressure baseline set by PEEP.

Although total inflation power, i.e., the energy per cycle multiplied by ventilating frequency, has been causally linked to VILI risk, not all combinations of the three pressure components of energy and frequency that sum to the same total power value are equally hazardous.

For injury to occur, a second requirement (apart from the raw power total) is a precondition; enough strain per cycle must be imposed to sufficiently distort lung parenchyma or disrupt vulnerable elements of the extracellular matrix that comprise the interdependent supporting framework for the alveolar network.

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