Alveolar recruitment: objectives and assessment?

Abstract

The alveolar recruitment describes the reinflating of previously non-aerated alveoli, associated with an increase in the amount of well-ventilated tissue and allowing an improvement of ventilation-perfusion ratio. Among patients mechanically ventilated for an acute respiratory distress syndrome, the alveolar recruitment is mainly performed by the increase of airway pressures (increase of the end expiratory positive pressure (PEEP) and recruitment maneuvers) and by patients’ mobilisations (prone positioning).

The assessment of alveolar recruitment at the bedside remains challenging and is often based on indirect methods, which makes its implementation difficult in clinical routine, in particular to titrate PEEP. 

We describe in this review the objectives of alveolar recruitment and the different methods to assess it.