Perspective reframes lung recruitability in ARDS around physiological response

Lung recruitability in acute respiratory distress syndrome (ARDS) is often described as the amount of nonaerated lung that can become aerated when distending pressure rises. In this Perspective, the authors separate three concepts: anatomical recruitability (potential), anatomical recruitment (aeration achieved), and “functional recruitability,” an interpretation of whether achieved recruitment provides physiological benefit relative to its mechanical and hemodynamic costs.

The authors say that recruitment’s significance cannot be inferred from aeration alone. It should be considered alongside respiratory mechanics, gas exchange and cardiovascular tolerance under the conditions in which recruitment is maintained. They use “recruitment futility” to describe little or transient physiological benefit, or benefit offset by the burden of achieving or maintaining recruitment. The term does not mean low anatomical recruitability or medical futility.

The proposed framework is conceptual, not a new measurement, threshold or method for setting positive end-expiratory pressure (PEEP). The authors note that recruitability and its consequences may change during ARDS, making reassessment under comparable conditions potentially informative when clinically warranted. They propose prospective evaluation of anatomical recruitability as a stratification variable in physiology-enriched ARDS trials; the article does not report trial data or establish a treatment strategy.